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When I first moved into the UDH, one of the very first projects my dad and I ever tackled was adding a small fence and gate to close off the back yard. In fact, it was the second blog post that I ever wrote — it was that early!

Since then, quite a lot of things have changed, including other improvements to the fence: replacing part of the chain link on the other side of the house, adding better gate hardware, planting garden beds next to it for added foliage (and to hide my neighbor’s fence that’s falling apart, which you can see more of in the pics below), and more. I’d like to think I’ve actually learned quite a bit about fences during that time. But last fall, there was a bit of an accident to this little section:

old and bent fence post

It happened during that awesome, sweaty week last summer when I rented a backhoe, ordered truckloads of dirt, and filled in the sink hole in a brutally humid August. My friends stopped by one night to help (truthfully, they really just wanted to play with the backhoe for a bit)…

…but as usual, it was my dad who helped out the most. Look at him go!

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Even though we got a huge amount done in that week, there’s was just one little step in the wrong direction: during one of the return passes through the gate to get more dirt…

…Dad turned the wheel and crashed directly into my fence. It wasn’t enough of a collision to take out the fence as a whole or for him to be injured in any way (and it was kind of funny since all bets would have been on me to be the one with a runaway backhoe), but it did just enough damage to loosen the concrete and make the whole thing unstable. The post had been bent to an angle that could not be repaired, so I would have to replace it in order for the gate hardware (actually, the newly-installed gate hardware) to close properly.

damaged fence post

I took the fence panel off and came up with a game plan to fix it, but I wasn’t in a huge hurry since I was busy working on lots of other projects all winter. In years past, I’ve used a bag of quick-dry concrete to set posts, so the plan was to buy a new 4×4, set it, reattach the hardware, and done (you actually don’t even need to separately mix the concrete… you literally pour the bag into the hole and water it down, poke it a few times to make sure the water mixes well enough, and stabilize the post so that it’s plumb — not a difficult DIY at all, just heavy). But as I made one of my usual supply runs to my local Orange, I spotted this little display:

sika post fix foam filler

According to the product’s packaging:

  • This new product could fix my fence without the inconvenience of carrying around 50 pound bags of concrete through the store — “effectively replaces two 50 lb. bags of concrete mix.” Since I don’t like carrying heavy stuff unless it’s part of an obstacle course race, this was a selling point for me.
  • The two components that are separated in the bag, once popped and mixed for about 20 seconds, form an expanding polyurethane resin that you pour it into the hole; in just 3 minutes, the product expands around the post and stabilizes it.

Basically, awesome.

Given that I also love trying out new DIY products and being the guinea pig to see if something *really* works or not, I figured it would make for a really cool experiment. For around 3x the price (online it says it’s now cheaper, but I remember spending a little more in person, so hopefully that’s just an indicator of it becoming more price competitive), it was more expensive than the bag of concrete I’d initially planned to use, but I liked the idea of trying it out and picked it up anyway. Could it really work?

The short answer: no. Not for me. But hey, I have cool pictures!

With the weather warming back up (and dry), the temperature was right to finally give it a try. I started by cleaning out the existing hole that contained the original post (any softer dirt, debris and such — Georgia’s red clay is pretty hard to begin with, but spring rain had caused some mud at the bottom of the hole). It may not look it from this photo, but the hole I started with was deep enough for the usual concrete that I would have poured otherwise (probably two-ish bags). I didn’t see the same details specifically on the bag, but an online video that I found for this product says the hole should be 8 inches in diameter and one third of the length of the post should be in the ground (which is a good bit deeper than I was used to digging if I were using concrete, so it was a little more prep work given how hard Georgia clay is).

digging out the fence post hole

I popped the bag and did a quick shimmy to get the two components to mix (note: there’s a very short window of time for this, about 20-30 seconds), then snipped a corner with some scissors and started pouring it into the post hole. The goop almost instantly started foaming up before I could snap a few pictures with my phone, which was pretty cool to watch. Over the next few minutes, I monitored the expansion and made sure the post stayed plumb (a post level would have been even better to use, but since I didn’t feel like making another trip to the store, two levels measuring both directions worked in a pinch).

Sika Fence Post Mix review

I stood around for another ten minutes, watching the foam expand even further and even above ground (according to package directions, you can just trim off excess after it’s hardened). You’re supposed to let things cure additionally for another two hours before attaching anything to the post, but I had other things to tackle the rest of the afternoon, so I let it be for the rest of the day.

I gave it a few test wiggles that evening (well after the 2-hour “fully hardened” window on the packaging), which proved disappointing. The product wasn’t super stable around the post, and as you can see in the photo above, had even pulled away from the post while it expanded. I was still outside working on a few other things, and I could clearly see the post swaying slightly in the wind. I chose to leave it overnight and decide whether or not to re-attach the fence panel the next day.

The next afternoon, I pushed on the post. While it didn’t fall over, it still wiggled at the slightest nudge — nothing like the secure stability of setting the post in concrete that I was used to. I guess one could argue not to expect they’d be exactly similar, except that the video I watched about the product literally had a guy climbing onto and hanging off the post as a demonstration of its strength. In my case, it took just a few more strong nudges, and the whole thing came right up out of the ground. Womp, womp.

Reasons Why It Might Not Have Worked

As with most product reviews, there are always two elements at play when things go wrong: either the product doesn’t live up to expectations/advertising, or user error (or well, I guess they’re not mutually exclusive, so both). I pick out products like these to avoid needing more time or effort, so I considered the other possibilities for why it might have failed. Perhaps the hole I dug was still not deep enough (the foam only came up out of the ground a little, similar to what I’d seen in the video, so it looked plenty deep enough for the equivalent in concrete that it’s supposed to replace). Perhaps the ground around the hole wasn’t dry enough (the product’s packaging didn’t really say much about water except to remove any standing water in the hole, and any loose soil had already been cleared out). So, while I’m sure I’d learn even more from trying it a second time, I’d had enough of my experiment. I certainly think it’s cool when new products come out, and I’m willing to try them, but if the original way was both pretty much fool-proof and cheaper, I consider this product disappointing, but at least I now know.

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UPDATE: Since there seems to be an issue with a (small) handful of commenters not reading the paragraph above where I acknowledge the possibility that not all outdoor conditions are created equal and why the product might have worked for others but not worked for me, I’m going to repeat myself a little (sigh — to the rest of you awesome readers, I’m sorry that people like this ruin everyone’s good time… I have zero patience when spammy, mansplain-y commenters would rather talk over me than read the information in the post that directly addresses their point): products sometimes don’t work for everyone and in every scenario. It sucks, but it’s also okay — it’s kind of what I’m used to with DIY (and it’s sometimes fun). If it works for you, I think that’s awesome. Continue buying whatever products work for you. There are a few different expanding foam products out on the market like this, so your results might actually vary depending on the manufacturer, too (I linked to a video of the product I used, but just note that there are a few I’ve seen listed online). Unfortunately, I can’t recommend this product based on this experience. And for what it’s worth, I had an experienced helper trying this out with me who had the same opinion as I did after seeing it come loose.

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The foam is easy to remove — I just hacked at it with a reciprocating saw and dumped the pieces. I noticed while removing it that the air pocket around the post was actually more than I thought; somehow, the resin didn’t stick in one spot around the post, which probably contributed to its lack of stability.

Sika fence post mix shows air pockets, leading to a less stable fence

With the foam shorn off, I grabbed an ol’ reliable bag of concrete and reset the post. Even though it took about fifteen minutes longer (well, a day of trying the other product and then fifteen minutes) to set enough to feel comfortable walking away, for me, concrete is the way I’ll go from now on.

This post has gone on long enough, but there’s more that needed to still be done to get my fence and gate fixed up, so I’ll save that for part 2. And if you saw on Instagram, even more was accomplished elsewhere over the same weekend (remember this project?). More of that is coming as quickly as I can edit the photos! Update: the trash bin slab is complete — you can find that here!

pouring small concrete slab

P.S. In case you’re wondering, this wasn’t a sponsored post or anything, merely something I saw in store and wanted to try out. I know how it is when you see a new product and wonder if it’s worth the extra cost compared to the alternative — which is often cheaper, but more labor intensive — so from time to time, I let my house test things out. In years past, manufacturers have even reached out later to let me know these posts have helped them improve products that don’t work out, so I hope you found this helpful too!

Want more project ideas? I have a TON of them, indoors and out! Here are just a few below (click on the image or the link to go to the tutorial). If you like what you see, consider subscribing. I have new projects EVERY WEEK and have also begun sharing video tutorials!

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176 Comments

  1. Well, shit.

    I literally just bought 5 bags of this stuff yesterday to do some fence repair. And I’m in Nashville so I’m fairly certain our soil and weather are similar. Damn.

    Thanks for the very timely warning, though!!! Back to Lowes for some concrete!

    1. I had high hopes, I really did! But I’m glad I caught you just before you wasted all that money. The concrete bags will serve you just fine.

      1. So I guess I’m one of those guys that you have to mansplain something to. You know the ones that get on your nerves. ;) In view of your photos the only possible way the foam could have done what it did was to be moved in the curing process (either by you, the wind, or perhaps a squirrel or a lemur ). Just because the foam has expanded and the outside feels dry doesn’t mean its cured. Unless your wood had some awesome foam repellent product painted on it. I think you should have tried more than one attempt prior to bashing the product. The benefit of this product is faster prep, application, and curing time. This is all my opinion and I may be completely wrong. Thank you for your site though. I look at it often.

        1. You are probably right. Part way through curing, this stuff if probably still soft enough to deform but no longer able to expand and fill the gap that was opened when the post shifted. Even when using concrete it’s a good idea to attach temporary bracing to the post to make sure it stays where you want it. That said, I’d still never use this stuff. Seems like a gimmick.

        2. Hey Matt, I appreciate your positive comment about Sarah and her amazing work. I am not sure what you meant in the way you included the word ‘mansplain’, (aside from some added hunour), but it is not usually used to describe a woman talking to a man.

          And thanks for your thoughts on Sika, it helped me choose my materials.

          1. Actually Sarah is the one who used that word and I was just reverberating back. You didn’t read her whole article i guess. But on a different note I now agree with her on the foam bags. I don’t like them and think it does have a tendency to pull away from the wood for some reason. Been wanting to change my viewpoint on here.

    2. I set dozen post for 6ft fence with this stuff and had no issues at all, was able to start putting fence together in two hours. Just saying it worked fine for me

  2. I love this post. It’s awesome to hear about products that DON’T work, instead of always hearing rave reviews from sponsored companies (which are totally fine, just a nice change of pace). Sorry you had a fail but thanks for the post!!

    1. I disagree, if mixed properly, it’s great stuff. I’m a contractor that guarantees my work and I never cut corners and I’ve never regretted using a polypropylene set. If it didn’t work I wouldn’t use it.

      1. I disagree with your disagreement… There is a contractor on youtube who’s family has been building fences for over 60 years, came to the same conclusions as this post. He did not recommend it after using 3 different samples. So you can see that just because it worked for you it doesn’t mean much. Now if you took the time to write a post or create a video on how to do it and how it works for you using X method. Now hat would mean so much more.

        1. But doesn’t that go both ways?

          You claim that “just because it worked for you it doesn’t mean much”, doesn’t the same hold true that if it doesn’t work for someone else……that it doesn’t really mean much either?

          Not really any more or less valid than anyone else that the product worked fine for them, or anyone that the product didn’t work fine for them.

          It’s like reading product reviews on Amazon, you have to take the good with the bad, and decide for yourself.

  3. Wow, all good to know! I may have to put a new mailbox post in. The post is actually rock solid, but the snowplows have nailed it 3 years in a row so the cross bar is no longer fixable and rot started in that section.

    Currently thinking of using the post as an anchor for adding taller 2x4s and suspending the box from chain on higher crossbar! So will plan on using cement.

  4. Looked good in the store display with it’s awesome sweat saving selling points but nothing will ever compare to good ole tried and true concrete. Depnding of the mix ( H2o ) just vibrate your mud in the hole well, trowel, and walk away in a short time, it’ll stay where you set it and cure. Who knows what could have happened Sarah, maybe air leaked into the bag or bad batch not to get the full catylist chemicsl reaction or expansion. I and a friend used this same technique to hold AGM Bstteries in place in the holds of our ocean fishing kayaks while adding saftey bouyancy. It was very easy to work with trimming any extra triple expanding foam off with good sharp filet knife after drying. Very similair to your pole setting componnet but reacts with air after leaving the can. Great Stuff it is, one wants to use gloves when using it tho ;-) Looking forward to seeing what you do with your bigger nice usable back yard sans sink hole / stump roots
    :-)

  5. May I suggest that you refer to the product by name in your post so your review would pull up when someone Googled the product? That would be super helpful.

    1. Very good suggestion, but there was also a reason I originally left it out: I think there are a number of competing products that use the same kind of concept (outdoor expanding foam), which is why I left it in more general terms since the poor execution as a whole isn’t likely to be specific to the brand. But in terms of SEO and Google search, the info is embedded into the post to help those who are looking for product reviews to find it (I’ve got feelers out there to my SEO friend to make sure I’m actually providing enough info for review-seekers to find it, but I’ll admit that I was on the fence about whether or not to go general or specific to the brand). If I get word back that I definitely need to list the brand, I’ll update it asap!

  6. The idea of foam seems unreliable to begin with- though it’s not as heavy it just doesn’t seem like a good idea. Still, you never know, and it would have been *so cool* if it had worked.

    We have a post for one of our gates that I guess they didn’t level or whatever so it’s going off to the side, plus erosion on the dirt/clay (we are in Georgia, after all) meant that under the gate was a big hole. We just plopped two bags of concrete down before it rained one day and viola- we haven’t fixed the sideways sway but our dog can’t just shimmy under the fence anymore. That’s why you’ve gotto love concrete mix, it’s stupid easy and strong.

    Sucks that the foam didn’t work out, but that’s part of the DIY right?

    1. Exactly! It’s fun to hope/experiment sometimes (if you can afford the risk), even if your instinct is telling you it won’t work.

      And I love your “just put in bags before it rains” approach!

    2. It worked perfectly for me, used 5 bags, 1 for each post.
      Performed as advertised! Thanks have checked it now and then and there’s no wiggle or flex in the post.
      I used in about 55 degree weather this spring.

  7. Great Blog!
    I’m in Canada much harsher weather conditions, crazy weather fluctuations.
    I have used this stuff hundreds of times in residential and commercial jobs. You are supposed to pour it onto the post and let it flow into the hole, if you just pour it into the hole it can get air entrapment just like your picture.
    The stuff is designed to compress and absorb the force of the wind hitting the fence then flex back when the wind stops, so it seems like the post is unstable where in fact it’s really strong.

  8. I don’t know how deep you hole was and if you did or did not widen the base of your hole and did you brace your post so the foam could cure ? I have not have had an issue with the foam post product. I have used it on 6x6x12 post to install 120 liner feet of post and have not had an issue.

    1. I have most of the details in the post, but I didn’t read on the packaging (or in the instructional video I watched) if you need to widen the base more than you would for a comparable concrete product, and the purpose was to fix a post that had already been dug for in years past (the packaging advertises how quickly it sets & tries to emphasize that it’s easier than concrete, so that’s exactly what I set out to compare). I’m glad it worked for you, but I would say that the average first-time user is better off with concrete based on my experience. Concrete is cheaper and pretty fool-proof vs. the foam (like I said in the post, there were possible issues with maybe the weather, or the depth of the hole, etc., but if the whole point is to beat concrete, I still say this failed in that respect). No homeowner should have to second-guess the setting of a post like this.

      1. It’s a shame this didn’t work for you. We’ve used it several times in No. VA with great success. DIYers also. Built our chicken run and a separate dog run with this product.

  9. You didn’t brace the post, that is why it failed. The movement form the post while curing would compress it and the foam would not decompress past the first couple of minutes. If you have done your plumb and level prior to pouring and braced it, it would have worked fine.

    1. The foam is supposed to set in seconds, so I held it level as the foam expanded, and the problem of the swaying happened well after it had been held in place for an extended period (whether it was done by setting up a brace or done by literally holding it in place, that should have sufficed since it was supposed to be <10 minutes of my time for the product to set). I’m not saying that a brace wouldn’t have possibly improved the outcome (it very well could have), but the point of my trying out this product was to see if I think it’s easier for the average DIYer who reads my blog to truly set up in the time it says on the bag (which is marketed as seconds/minutes and less time than the concrete option, which you can also set very quickly without a lot of bracing efforts and by holding it in place until it’s set). If it still takes lots of setup time, or if I have to dig a deeper hole, or it’s taking comparable time to the cheaper, original option of concrete, then I don’t find this product simpler, faster, or better for DIYers, and I don’t think the marketing matches up to the actual quality of the results. I don’t think the marketing matches the results.

      1. I think Casey is exactly right!! I just used this stuff on a mailbox post which i held plum by hand. The littlest motion during those critical setup moments cause gaps in the final product. Thankfully it was sturdy enough for my use!

  10. Thanks for trying this out! I just bought a house and was looking to see if this stuff might be easier to use than concrete for a project I’m about to do, but sounds like I should just pass. Sorry you had to spend the extra money, but you saved me from having to do it! :)

    1. That’s the idea! I’m happy to experiment on products sometimes, even if they don’t work out for me for exactly that reason. If I can save someone a few dollars and a headache from being disappointed (or having to do the same project a second time), I’m glad I tried it out!

  11. There are many people who say that you shouldn’t use concrete when setting fence posts as the concrete will speed up the time it takes for a post to rot away. Here where I live, which is the island of Nantucket, we have sandy soil mixed with clay and dirt. We usually dig 24-28″ deep for a 6′ fence (8’post) and put gravel at the bottom and fill the rest with dirt. It holds extremely well and withstands hurricane force winds. And when the post starts to rot it’s easier to replace. Perhaps in an exposed corner we might use concrete but usually not.

    1. I get that. I’ve heard some pros say concrete is fine, and some pros say it isn’t. I think another factor in rotting is whether or not people were using posts that are approved for “ground contact” (I’ve only recently see this well-stocked in stores around my area). Some pre-treated posts aren’t approved for ground contact and if they’re used for fencing, it will lead to rot a lot faster. I’ve used a combination of concrete and then filling in the top part of the hole with packed dirt, and I haven’t had any rot to deal with thus far (the only issues I’ve seen with my house have been neighbor’s fences, not my own). But I will note the gravel/dirt idea, and thank you for your comment!

      1. Whenever wood comes in contact with concrete, it WILL always rot away, even the pressure treated wood will rot. The “correct”(though I’ve never seen anyone do this) is put tar on the bottom of the post where it comes in contact with concrete/dirt

        1. Thanks, Brent. When I put in my floating deck this year, I found similar info about using sealant or flashing tape.

        2. Yeah, painting the bottom of the post with tar or something like it is a must, even for h5 pressure treated. I use a solvent based tar coating. My mum used creosote.

          Would like to see Sarah learn how to mix her own concrete – I swapped from bags of premix to just getting cement and making my own concrete in a wheel barrow, and it saved me a lot of money and made for a much nicer finish.

      2. Wood doesn’t rot because it’s in concrete. Wood starts to rot where moisture and air mix. So even if it’s dirt packed around the post it’ll still rot where water and air meet. And using that treated garbage on a fence is dumb. Post with twist apart from the rails. Pickets will wave all over the place. I’ll only ever use cedar or Douglas fir for a fence. Looks better and last just as long if not longer. Oh and you don’t seal/paint any wood till it dries. Otherwise all you’re doing us sealing in the moisture.

        1. Good for you that you’re happier with a different option, but pressure-treated wood fences are common and hardly “garbage”. Georgia has lots of pine, and purchasing it usually supports local lumber mills, which I think is awesome. People will use what they can afford and what’s most accessible, so I don’t see anything dumb about that either. If you’re going to stain it or paint it after it’s had time to dry out, the difference is negligible IMO if you properly maintain it.

      3. I’ll try not to be “mansplain’y : ) but I think you’re right. I’ve done rapid concrete posts before and have sometimes hand held them and they cured with no problem, but with the foam, there seems to be a period in the curing process where any little movement will cause a slight depression in the foam and ruin the structural integrity. Even with the short curing time you really need to brace the post to ensure no movement. Im sure it can be done handheld but if you want to avoid a botched hole, bracing is the way to go. That takes away a bit of the convenience for me. If I were to use foam I would ensure the hole is deeper (up here in Canada we need 4ft due to winter frontline) and I would create a slight bell shape at the bottom of the hole to get a good anchor. If it’s a post that will support a gate I would strictly go concrete, I dont think foam would last in that application.

        Anyway keep up the great work Sarah, I’m enjoying your blog.

        1. Thanks for the input Mike, well said, and I completely agree! Needing a brace takes away a major convenience factor for me (and I think it does for a lot of homeowners who think of this as a quick and dirty “I’ve got the time and energy for the moment but I don’t want to deal with this all day” type of fix). I think it’s also because this was a repair and not establishing a brand new fence that I also wanted convenience most of all. At least, that’s where I’m coming from. Combining that with the extra cost is largely why I decided concrete is my better option. It’s fine for those who want to still use it, but it was a good learning experience no doubt.

  12. I just came across your blog…I just purchased an umbrella style outdoor clothes dryer, and was wondering about this type of foam installation….I had seen it somewhere in a store. Glad I read your trial, I too will go with the concrete…lol. Thanks again. I think I’ll subscribe….I enjoyed your commentary

  13. I have not used the two part mix sold by the box stores, but I have used the two part expanding foam sold in 1-gallon bottles. I must say this is one of the best products I have ever used. We set our neighborhood mail box posts in foam while all of our neighbors thought were out of our minds. I also used it on some fence posts that were rotted out and it secured those posts better than the new ones set in concrete. I wish I would have kept the video that was showing the testing of the concrete vs. foam, search and you can find it, as the foam beat the concrete in every test.

    1. Good to know! Thanks for telling me — I’ll have to give that one a try at some point. I’m sure that with each manufacturer/application there will be some differences in results. I’m definitely noting this for future post-setting. Thanks again!

      1. In my experience, the foam cannot be moved at all after it begins to expand. It is kind of like a pancake mix beginning to cook after poured into the pan. Once the post is moved it bends the soft foam out of place , and wallya you have a gap between the foam and post. Also if you leave only a small space between the post and dirt i.e. the side, the foam cannot expand in between to form enough ‘beef’. I wouldn’t use it anywhere the post might get bumped by a car or lawn mower, it crushes easily. as far as fence post, i might consider using in between the ends or alternate on post, but your corner post or gate post always need to be extra anchored. The stress of the fence movement travels to the end of the fence. I plan to use some on a water pipe coming out of the ground for insulating purposes only.

        1. I think you’re right on the money here. I think this would be an excellent consideration for when it would and wouldn’t be a good alternative option. Thanks for the comment!

    2. When you put gallons, you can get any strength/density of foam you want. Hanging a heavy gate? Get denser foam. It’s also cheaper by the gallon.

  14. I have a question and a comment then i will exlplain where they come from.
    Does the bag have what the two chemicals in the bag is? Ive looked at home improvement stores in my area and cant find the bag to check for myself. Also cant find it online. And i would like to know what it is before trying myself
    Looking at you pictures it looks lime to much mosture on the post.
    Im getting these idea because i am a spray polyurithain foam insulation contractor and if the two chemicals are the same then the A part is Isosianate wich react with water. Mosture causes it to react instead of mix with the B part corectly. I am guessing it is the same due to having the foam look the same when working.
    Or it is not the same and nothing i have said helped you or anyone else

    1. Haha, Jimmy, thanks for your comment (and loved that you added the bit to the end). It IS the kind where you mix two chemicals and then the reaction makes the foam expand. And while I’m 100% in agreement with you that a chemical reaction like this could possibly be influenced by rain/water in the soil, I would look to the instructions for providing this info — I was curious about the same and the instructions mentioned getting STANDING water out of the hole but nothing more on total days without rain, etc. I even dug out a little more soil at the bottom of the hole as part of my test (after waiting several days after it last rained, but since it was spring/summer weather, the soil isn’t going to be completely free of moisture at any time during warm weather in this geolocation). So, in my opinion, I would recommend that the packaging be made more clear about weather conditions such as how many days to wait after it rains (paint products have this kind of labeling), and other such helpful tips to quickly resolve a fundamental element to installation. Usually where a key element is left out and then results in user error, it can be resolved by better labeling (since you obviously have more experience at a pro level, these things might occur to you naturally but wouldn’t to your average homeowner who is looking to make this a 15-minute project).

  15. Thanks for the info. Enjoyed your review and experience….. I thought I had a water leak under a concrete side yard – but on investigation it probably is my neighbor effecting my property—-anyway it is where my gate post is. Tried to shim the gate and noticed a small one inch opening which when I stuck a metal ruler into seems to be about eight inches deep. Thinking about enlarging the small hole and reinforcing the fence post with a metal piece pounded into the hole and connected to the fence post and fill the entire hole with the ready mix. The foam sounded like it would be easier but I did the ready mix is probably a better fix

    1. From one person I heard that it’s better to not use these on an actual gate post like this. I think ready mix is a better choice!

  16. Despite how the product performed or if you cut the wrong corner off the bag ? this is one of the BEST posts I’ve ever read!!! Bravo!!!

  17. Hi Sarah, Read your article on the post foam. I just retired from the power company in Florida last year. We use a 2 part foam mixture to straighten leaning power poles. Granted different use and probably a different foam compound but worked very well.

    1. Good to hear! I had high hopes. Maybe in a few years I’ll give it another try (and I agree, probably different results depending on the compound used). Thanks for sharing!

  18. Thanks for this post. I trust your experience with this product and will not give it a try. I think you’re supposed to buy a hundred bags of this crap and just pack them all tightly around the post. Foam versus concrete? Seemed too good to be true, anyway. Nice blog.

  19. Thing is, as you say there are 2 factors at work. Either or both could be to blame.

    I would say once poured the post must remain 100% stable otherwise the movement will create the issue you faced here.

    In general, something that is too good to be true generally is. Cement would be my option ;) Expanding foam, once set, is also fairly rigid but would I use it on a fence post? Na, I doubt it.

    Good to see your experiences and tells me not to try it ;)

    1. That’s (partly) what I’m here for! My results might help others to make the right choice for their own home’s needs,
      so I’m willing to take the bullet, so-to-speak, if it helps other homeowners save some money (some claim not to have problems at all too, but yeah it could be multiple factors at play here that aren’t the product alone).

  20. Thanks for the great post (hah, pun intended). I saw this product and was considering buying it to do a back yard DIY deck project. I think I will stay with concrete since my granddaughter will be usiup the great informative posts.

  21. Your comment about folks who comment without reading everything reminds me of a quibble I’ve had since my school years; I don’t like the idea that there is no stupid question. For my two cents worth, if someone asks a question that has just been answered while they were not willing to pay attention is a stupid question. Not a request for further information, just the same question from someone who has decided to finally return to the present from whatever alternative reality they had been exploring and wants everyone else’s time wasted.

      1. Thanks; I enjoyed your article and I saw it because someone posted the ooh-la-la video about it, and I questioned it. This is not to say that I always read everything and check out all neat-sounding posts online, but I try to.
        Thank you for this information about a neat-seeming product.

  22. Thank you so much for your notes and pictures back to cement for me. It would have been a great product if it had worked. I just don’t have the time, to lose a days worth of work. Again… Do not listen to the blah, blah people! I appreciate your comments.

  23. Thank you SO MUCH Sarah! I am an older lady and saw this product on FB, got pretty excited because I am always looking for DIY projects that I ACTUALLY can REALLY do myself. I appreciate your honest review and am grateful that someone else tried it and then took the time to give it a review. That saves me time and a huge headache! :)

  24. Thanks for sharing you’re experience with this product. I was wowed by its advertising video. Although, the image of the 56 year old construction dude “pole dancing” on the test post was a little disturbing . . . Moving right along . . . LOL!

    I think on this piece you took too long to get to the point, which (I think) was to report the positive or negative results of using the product. I noted your later frustrations over people not reading your full story before commenting about your use of the product. You titled the piece ” Fence Post Foam Vs Concrete”. However, It seemed like 75% of the text was a story about the entire project . . . and not “the product”. I clicked on your post to read about the product and after starting to read about the old fence post, neighbors, your dad, etc . .. I was compelled to scroll down to the end to find the info that lured me to your your link. I feel I got what I needed at the end – I didn’t need the rest.

    I do like the way you write. However, I recommend that you put the salient info up front (i.e. start out your opinion and results). Put the bottom line up front,, and then continue with the details for others who still have questions or may be interested in the project. This way all your readers get their itch scratched whether they want a simple answer or details. Unless you’re writing a suspense story or have an ulterior intent, let the reader in on the answer right away. They’ll remember your direct frankness and be more likely to return for more.

    Good luck, Thanks again for sharing your experience so that we can all gain from it.

    1. Yeah, the video is… entertaining? Haha.

      And thanks for your opinion on the content; I get your point and would be in agreement with you if this were primarily a review site and if that were the kind of audience I cared most about converting. But to the point, most of my readers aren’t the same as what this post draws in from Google search. The traffic from it is nice, but to invest more time into catering to a person who would bounce into my site, read the first line, then bounce out, wouldn’t serve my steady subscribers (who want the story) or myself (who wouldn’t benefit from the time invested or the advertising revenue for the time spent to change the whole post). It could even be negative to increase “bad” statistics from people coming in and leaving so fast, or to try to get subscribers from an audience who wouldn’t like the rest of what I write about. I changed the post’s title once I saw people were looking at the post for that info, but reorganizing the ENTIRE content too would be a lot more time, and could even just result in more condescending comments like I did when this post started gaining traction. So, to change it to get more of that? Meh. Good advice to give this one post more traction. But I would rather focus on building new, awesome shit.

  25. Hi Sarah
    Thank you for this informative review, love your style! As to digging post holes in your Georgia red clay, next time you have a post to set may I recommend a Seymour Iwan Auger (google it.) This magical six inch hand auger is a lifesaver! (and back saver) I just set 13 4″x6″ retaining wall posts 36 inches deep in California drought hard-pan lickety split. WAY easier and more efficient than a clamshell type post hole digger or shovel. 36 inch deep hole done in approx 20 minutes each. And Amazon delivered it to my door in two days. Couldnt be happier

  26. I live in Ontario, soil is usually wet due to the harsh winters and hard rains we have, during the summer the soil can get rather dry [sometimes] Our lands are a mixture of soil and sand, I love to garden but have to buy a ton of topsoil due to the sand location we live in, so I’m thinking this may not work unless I dig a hole larger than what I need and pack it with topsoil and then pray LOL :) Great post, I want to put up a clothing line, so I may just try this out, can’t hurt none and like you said, could be my error or the soil I’m going to be using to do the job, either way, it will be fun to give it a whirl :)

    1. I read from a few other commenters that some folks have had success with it in colder climates, so I hope it works out for you! If you think of it, feel free to come back to this post and let me know if it worked for your line after all (I’m sure others would be happy to hear your results too!). Good luck!

    2. I am also in Ontario (high five!) and I am looking into this product. I am curious about your reaults! The soil in my area (Great Lakes) tends to be sandy and loose. So I am also reading up to see if I can get away with making a slightly larger hole tham usually done with Sika fill and then packing some gravel along the side to help. Since foam fills apparently rely on the soil itself for support, maybe this will help??

      Good licknwith your project!

  27. I didn’t read all the comments, so my apologies if this has been addressed.

    I too have seen the ads, and I definitely wondered if this stuff were too good to be true. Even the video you mention where the guy is hanging off the post the post seems to be moving more than I would expect in concrete. But, the one thing from your blog that seems like it could possibly fail to be following the directions is the size of the hole. Your text says the hole is supposed to be 8″ in diameter, and the hole in your photos seems to be much larger than that. I don’t know if it would have made any difference, but it certainly seems like it ought to be mentioned in the text IF it was larger – as it appears. In their videos they show much narrower holes dug with post hole diggers instead of a shovel.

    Anyway, thank you for testing and for sharing. Sadly, your results seem to be far more like I feared than like I hoped

    Kurt

    P.S. After driving into the original post, shouldn’t your dad have at least had to help with the repair??? ;-)

    1. Haha you would THINK dad would have been obligated to help, right? I let him off the hook because he was so helpful with getting the yard leveled… you take the good with the bad. ;)

      Could be about the hole; it’s possible that the size too big (mostly the hole left after the old fence post came out). It is probably a number of things that just simply added up to not being the right product for my needs. I think another poster was right too that it just shouldn’t be used for posts like this where it has a gate constantly interacting with it (maybe for in-between fence posts but not one on the end). I’m sure that it still has a purpose for some projects, just disappointing that it doesn’t work as a true replacement.

  28. Is there any possibility that the foaming polyurethane not-concrete didn’t get mixed thoroughly enough? You kind of skim right past that process – “a few shimmies…” I think you said, but that could have been for the sake of composition, writing an informative piece that’s fun to read and not boring. But the stuff would definitely be weaker if it were not thoroughly mixed, so I was wondering.

    1. You’re supposed to be able to mix it within just a few seconds, according to the packaging. So, you basically bust the seal that separates the two parts of the mix and slosh them around, then you try to pour it in the hole super-fast before the mixture starts to expand in the bag (and not in the hole). So, I’m confident that I mixed it as required on the packaging.

  29. Thanks for trying this product before I waste my money. It’s super expensive here in Australia. There’s also some useful tips in the comments but those tips should probably be on the bag if Sika want their product to succeed!

    1. That’s sometimes the difficulty too with having a new product out in the market, I bet. Or possibly if trying to target a new market, say from pros to DIY homeowners. I’ve been on the other side (in the technical/design world) where you try to anticipate how someone is going to understand how to do something, but even the best Q & A teams might not catch all of the real-world experiences needed to properly instruct! I hope you find the right products for your project though!

  30. Thanks for the information. I think I will just stick with concrete. I am not that patient for my hard work and then the product do me the same way.

  31. Really wished this had worked out for you. I am dreading lugging thousands of lbs of cement to my back yard for my DIY zipline project. Anyways I guess I really shouldn’t risk it with the kiddos lives on the line (literally). Thanks for the review!!!

    1. No problem! Remember that each product is different so while some pros have EXCELLENT results with a product like this, I didn’t find it as easy to use as the advertising claimed on the packaging. I’m glad I tried it but I hope that it lets other home buyers make the right call for their own homes!

  32. I was searching foam post setting and came across your page. By looking at your pictures it doesn’t seem that you had the post deep enough even for concrete. Again I can only see what the picture shows. And the amount of foam on the post looked like maybe 12” of coverage. I have personally never used foam to set post still thinking of giving it a try to see how it works. I have tryied new things and they didn’t work so well the first but the second time worked awesome.

  33. Loved the blog. Answered some questions about this stuff that I had… The only thing I have to call foul on is your comment about where you were shopping when you saw this stuff… You said your “favorite orange” which happens to be who I work for… And I know for a fact, we would NEVER have put that demo out in the aisles in one of THOSE blue buckets… It did give me a laugh catching that though. Again, great blog! Thanks.

    1. Wow, good eye! I shop at both of them so often that I didn’t catch that, even after looking back at this post MANY times (also since not actually using the name of either company). But yes, I would bet you wouldn’t put a demo out in a blue bucket, ha! I’ll be changing that shortly!

  34. I have no experience of this product but looking at the picture of the extracted post, it seems there was no product at the base. In effect, that ‘ring’ of product has offered no stability. I’m in the UK and may try the product on a small project as a tester.
    Thanks for the article.
    CJ

  35. HI, cool blog you have here. I also was curious and bought a dozen bags to set a few posts. Works like a champ! Having used many types of urethane and foams for many years I will say that looking at your post pic, it appears to not have bonded because of a poor mix or a wet spot on the post. Also, I found out using this foam isn’t like the typical concrete use where many folks have the bottom of the post sitting on bare dirt instead of sitting in/on concrete [or the foam in this case]. It needs to completely envelop the post to support it properly from my experience. The posts also need to be fairly clean from any mud. What I’m now curious about is the longevity of the foam. Cheers!

    1. Glad it worked for you J.T.! Very good tips, and thank you for posting them. Not that I speak for ALL DIYers of course, but I like to think of it in terms of “Do I think that the beginner/average homeowner would find this pretty foolproof if I have less than stellar results?” and post them, good or bad. You said it yourself that you have some experience with foams, which I’m sure helped you get a better result too. I definitely think there is room for improvement, perhaps as simple as providing better instructions on the bag so anyone who isn’t used to working with urethane/foams know the right conditions and don’t make assumptions based on their experience with concrete (I think that was part of my problem; the marketing of this product directly compares itself to imply that it’s as easy to use as concrete, but obviously if they have completely different conditions that affect the outcome, it’s an issue with instructions/marketing on the bag, too.). Fun experiment for sure!

  36. I am so glad I stumbled onto this post as one of my sons and myself will be putting in posts in the next month or so. I nprobably would not have bought this product because of the price, but I may have been lured by the video of how easy it would be. Thank you so much for posting. May you have a blessed day.

  37. I was talking to someone about putting up a basket ball post, He showed me a video of the quick mix no water product. Sorry, wasn’t sold on it from first glance. With a product you can trim excess with a knife, doesn’t make for a sound base for a basket ball post with all the wiggle it will receive. A person night as well us expanding foam in a can with sane results. I’m old fashion. I like the sound of concrete being used far more than foam. That’s my opinion. Take it or leave it

  38. Thanks for heads up, was off to buy the S brand foam for two metal chain link gate poles today…hitting the breaks and going for quick setting concrete instead ((sigh)). I had reservations anyway, but like you, love to try new stuff, except I don’t really want a redo.
    Might actually try for mailbox post, but my dogs have to stay securely in fenced yard.

  39. This is a great blog article, well done.
    I got to thinking, as I was reading through it, that this could be an example of something I experience fairly often: Poor manufacturer documentation. Nice puffy videos, but little or none of the important stuff it seems you have to learn the hard way with multiple failures. I’ll bet if you had had multiple posts to set, you’d have been to write a fine article telling us about all the gotcha and things you have to get right.
    Personally I’m a fan of the no-concrete approach because the ground here is full of big rocks and i learned as a boy how to tamp posts properly. Broken fence posts set in concrete in rocky ground are hell to fix. I’m actually thinking I’ll drill out the old cedar posts and replace them with steel ones. I’m just trying to decide whether i can use polyurethane foam to shim them.

    1. Thank you and well said, Ken! I agree. If a manufacturer is trying to take a product from the commercial environment (where there are experts who already know the product and its limitations well) to the residential, it’s hard to think of how a beginner might encounter the same process. Once the marketing turns toward the average DIYer, they should test it on a focus group or something. Ultimately, the better instructions will result in less user error. I hope, in time, their instructions will improve. There aren’t many rocks that I encounter in my yard, but Georgia clay is a beast of its own to dig in!

      1. Thanks Sarah,

        Granted this is a little off topic, but one of my all-time biggest peeves is lack of understanding of the need for user testing, in this world where we keep coming up with new things for people to use,

        And it’s so easy! All you have to do is give your product and literature to someone who has never used it before, keep your mouth shut and watch what they do. No fair hinting!

        Developers are the worst people to write user manuals — they totally can not see it from the other side!

        1. Ken, I totally get where you’re coming from. I was in software for a long time, so it sounds like you know that world well!

  40. Great article, and cool website! Just yesterday I tried out the product in question, and I did read your article first, so it was done with both eyes open. I was installing a 4×6″ x 12′ post for a large bell at my lakehouse in Anderson, SC. It appears to have worked well, though because I dug the hole extra deep, I might have considered using two packages instead of one.

    The only gripe might be that I didn’t get a nice foam fill 360 degrees around the post – it seems there was almost a quarter that didn’t quite foam enough. This might be due to my rush to get the epoxy mix into the hole before it exploded on me, but the rush was really unnecessary. I was literally just pouring a liquid mix into the hole with ample time before it started to react. If I had taken a little more time I might have gotten better results.

    Fairly dry hole, break in the otherwise rainy weather, so can’t really blame moisture. In any event I’m packing extra dirt into the hole and holding my breath. The post appears stable, but I’ll know when the bell is up if the foam is doing its job.

    1. Glad to hear, Hal! That was my hope with a post like this: making sure you know what’s up so you can avoid the problems I had. Sound like your install went far better. I hope it lasts a long time!

  41. I read some of the comments below. I apologize if this question was asked and answered. When I was told about this product, one of the selling points to me was that utility companies use it to set utility posts. Seemed to me if it worked for them it should work for my little ol’ fence posts. Comments on different sites are all over the board, some similar to yours and others raving. What I’m wondering is if the soil conditions make a difference. I’m in south Texas, so dry and rocky, not clay like yours. I realize they don’t advertise it only works in certain soil conditions, but do you think that could have something to do with it? Also, I’m hanging welded wire on it, so probably lighter than a wood privacy fence. Maybe it doesn’t need to be a strong (though it shouldn’t be wobbling around)…
    thanks.

    1. Good questions, Michael! I didn’t see anything saying to expect different soil types either. Perhaps it has more to do with the size of the hole, the weather/wetness of the soil, etc. Others are saying that it’s a good idea to really pack in more soil before/after and to make sure the area is totally dry (one person emailed me to tell me they wanted to eliminate water being a possible issue, and had success). If you wind up giving it a try, please feel free to come comment back with your results so others can compare. Thanks for reading!

  42. I had a similar experience with a clay soil. Had some water that I drained out, but even with 30 Celsius/86 Fahrenheit weather, it was “cold” in the hole from the damp clay, I believe this is where this products will fail. As with all different expanding foam, it needs specific conditions to chemically react properly, cold and wet does not do it.

  43. Great post Sarah, thank you for the detailed information. I’m in the process of replacing 60+ linear feet of fence and have been researching options including viable alternatives to concrete, if any. One thing to note about epoxy foam based on my research, specifically, Sika’s post fix, it is not a hydrophobic foam (reacts to water) and it does not meet ASTM standard D1621 (test method describes a procedure for determining the compressive properties of rigid cellular materials). I won’t go in to details but it’s something to consider when using these products. There are others out there that meet such standards and after much search I found one. But as they say, the proof is in the pudding, I will test it out on a couple of posts before moving full speed on my project. Who knows, it might all be a waste of time and I’ll end up going back to good’ol concrete.

    1. Thanks for commenting, Mike! Glad you found it helpful. Great note on the differences in products out there, though I’ll admit it sounds like you’ve already done far more research than I did before trying it out! Lots of luck with your experiment; I hope it works well for you.

    2. UPDATE: After much research I ended up using Quikrete 50 lb. Fast-Setting Concrete Mix for my project. This product didn’t require mixing. Just dig the hole, plumb / level your post, pour in the bag and add a gallon on water. The mix dries in 30-40 minutes so I was able to get my 2×4’s and fence boards up the same day. Very happy with the product. The project went so well that I ended up replacing the entire fence, a total of 180 feet Cheers!!!.

  44. Your review was helpful, right up until you used the word Mansplain…

    Now I just assume you are a dimwitted snowflake and I can’t trust that the issue actually wasn’t user error.

    1. I would only be dimwitted if I refused to admit that user error or bad instructions could have been part of it, which I covered plenty in my post. And “mansplain” isn’t a proper noun, so no need to capitalize (I only bring it up since you’re so eager to attack my intelligence). Have a great day!

    2. Dude, I think you’ve been triggered. Hyperventilating over a single word?

      I just wanted to come back and report that the post I set a few months ago with the Sika Post Fix is still working fine, and even helped out a neighbor who decided to try the stuff as well to fix a mailbox post. And then I come across this annoying comment. We’re all friends here, okay?

  45. If you read the instructions there is a recommended size for the hole. 8″ X 36 ” it appears in the photos above that it was only dug at max about 18″.

    1. It could be that the instructions have improved since my experiment, but I double checked the package when trying it out and and there were no such recommendations. I believe it said an 8″ diameter minimum.

  46. Thanks for the review. I saw the ads for this and wondered if it was worth trying on an entire privacy fence. After your review, I’ll pass on the product and use concrete. Better safe than sorry! Concrete works, although slower, the first time (unless you forget to measure and use your levels….)

  47. Looks like a product for the week and/or lazy. Quikrete is the old reliable, dependable, extremely easy to use, and inexpensive. Man up next time and load those bags.

  48. Whats wrong with dirt? I use 10 footers and dig 36″ to 42″ down. Tamp it with the dirt and rocks that came out of the hole. I use the expandable seymour digger, regular phd, and a digging bar. There is usually enough room to tamp the dirt around the post with a 2×4. Use a post level and keep adjusting and tamping often.

    There is a lot of great information out there from experienced fence builders that suggest concrete speeds up post rot. Regardless of longevity when a post does need to be replaced its much easier. With concrete they can snap at ground level once they rot making things even more difficult,.

    If I was going to use foam I might try setting the bottom 18″ in dirt and when thats plumb and tamped add a few feet of foam on top.

    1. To my knowledge, there’s nothing wrong with dirt if that’s what you’d like to use, but I have never done it in Georgia clay. Whenever talking about digging post holes, the area you live in can make a huge difference on what is easiest (how far down is considered the frost line, type of soil, etc.). Digging 42″ down in GA red clay is pretty tough, so concrete has just been the easier option growing up and how my dad taught me. So, it’s a combination of being my go-to for how I’ve set posts before, as well as what the foam product was comparing itself to (the in-store display and labeling was saying it was easier than concrete, replaces concrete, etc. so it was a direct suggestion to what to compare it to).

  49. Thank you for the review! I am using Sika on a fence and am really curious (with some trepidation) to see what happens after the coming winter and spring. We are at 45 degrees north latitude and have a long winter with lots of severe freeze-thaw cycles. I really went to town digging my holes and the posts are sitting on bedrock at around 36″ below grade. It sure is a treat to work with compared to bags of concrete!

  50. I really enjoyed your comments on use of foam for setting
    Fence posts. I was even nervous about putting quick
    Setting mortar in dry form around my fence posts. I think the bag said add one or two gallons per bag. They are
    Holding fine but I wouldn’t want to dig them up to
    See if the mix had a uniform consistency. Thank you.

  51. WTF is going on with that fence in the first picture? I had seizures looking at it. No offense but did you maybe not think of getting ideas from google before you did that? And the 2x4s in place of the non 2x4s on the panel fence? Fly me to your house… Id love to fix that mess. No offense. I really just wanted to get opinions on the opp concrete for posts but I cant trust your review. Sorry… and best of luck. :)

    1. I can’t make sense of your comment, no offense. You’re all over the place slinging insults at a fence I didn’t build, and then saying “no offense” as if it somehow makes a comment intended to insult not an insult? Best of luck to your seizure problem, bro.

  52. I found this blog after checking for reviews on the Sika product after buying two bags of it in an emergency today because I ran out of another foam-based product that I bought in gallon jugs from Amazon. I found similar results (in Kansas) where the Sika foam expanded, but pulled away both from the post and from the edges of the hole. After 45 minutes, I found the post (26 inches deep, 4×4 dry pressure treated post, and a dry freshly-dug hole), the post was still wobbly. I had already set 7 other posts using a different brand of foam (that brand claimed I’d have enough material for 10 holes, but I only managed to fill 7). The Sika product allowed my thumb to indent into the foam, whereas the other foam product wouldn’t even let me press my fingernail into it. I ended up pouring 10 remaining ounces of my other foam (after mixing “A” and “B” together) into the cracks, and that secured the post enough to not wiggle around.

    I suspect the Sika product has some kind of defect with pulling away from the edges, preventing a tight bond with both the soil and post. I’ve reordered more of the other foam (Secure Set) from Amazon and will take my other bag of Sika back to THD. Very disappointed.

    1. Good to know, Jason! Thanks so much for your comment. I’m glad to hear you had the same result as me and that there could be a better alternative out there; very helpful info!

  53. Agreed, I wasted 20 bags of the stuff, 3 days after they went in, we had a good amount of rain drop and now every posts wiggles 3-4 inches. Have to go and get concrete now.

  54. Great post! I actually just set five fence posts after doing a bunch of research on this product (including reading your review). The reviews I’ve seen have been generally positive but with a not insignificant amount of people experiencing issues just as you did. I decided to give the product a shot the portion of our existing fence that needed replacing fell over after a big windstorm and the posts (rotted as they were) snapped off at the ground. Cue the joys of digging out enormous concrete footings!

    I honestly don’t know that I can contribute much to your post given how thorough it is (I’m also a total novice to fence building), but maybe sharing my experience will be helpful to others? Here’s something to keep in mind–even among the packets that I purchased from our local big box store, the packaging and instructions were slightly different. I went with the instructions that Sika has posted which state that holes for non-gate fence posts should be 8″ in diameter and 36″ deep (presumably for a 6′ foot fence–that’s what’s pictured on the packet). The instructions on their website also call for mixing for 15 seconds. The other packets had vaguer instructions and only listed the 8″ diameter requirement but nothing about the hole depth. I will be totally honest and say that, given the extremely thick clay soil around our home, some of those holes were definitely closer to 33″, 34″, and so on. What a pain!

    Swallowing my fear that the bag would immediately explode upon puncturing the seal, disfigure me, and curse me to a life known as the supervillain “Foam Man,” I poured in the material. By the time the foam had set, it had expanded up each hole up until about 3″ or 4″ from the surface. That seemed about right since I planned on backfilling the holes so that grass could regrow around them. I left the posts alone for 2 hours (supposedly the full set time before placing a load on them) and gave ’em a test wiggle.

    So, like I said, I am not some expert DIY home improvement guru and I defer to pretty much everyone’s wisdom (including yours!). That said, the posts seem pretty well set. There is obviously some flexion above ground but not much more than I get from the other fence posts that survived the windstorm and are set in concrete. (But there’s no way I’m going to hang off any of these fence posts with my full body weight!) I think another poster mentioned it but I’m guessing the whole point of the product is to allow posts to flex when hit with a heavy load, dissipating the energy, whereas if a fence set with concrete gets hit with a big enough load, the first thing to give is going to be the wood instead of the concrete.

    Today is a day off with the rain but I plan on hanging rails and installing pickets later this week provided everything is still good after the rain. I’ll let you know how things go! Again, thanks for the review and big fan of your site!

    1. Thank you SO MUCH for coming back here and sharing your experience. I think tons of folks will find it helpful when they read it. Sharing the experience is 100% my goal, either good (or in this case, bad), so that others can do a better job. So thank you for adding to it. To think, I almost didn’t post about it back then, and I’ve since learned from the comments on how much writing about it going wrong has helped people get it right. And yeah, that part about not quite having the same consistent instructions: I totally felt the same way! So glad that it worked out well for you!

  55. I’ve also had bad experiences with the Sika foam set products. I went to Secure Set after some testing. I’ve had about 200′ of privacy fence anchored with it for the last year. No wobble, no shakiness. You pay a little more, but it holds together pretty well.

  56. I don’t know what video you watched, but both the instructions and the FAQ on their web sight make it clear that it won’t be as strong as concrete, to the point that they explicitly recommend that you do NOT use it for gate posts or anything structural.

    I’ve used it and have been (mostly) happy, but I went into things knowing its strengths and weaknesses, and only used it when and where warranted.

    1. I know that back when I originally posted this, I linked to the video source I watched. But given that it was over a year ago, the video link may not be as valid as before. Good to know though, thanks for commenting.

  57. Thanks for this – I’ve been researching the expanding foam stuff, because I also have a strange aversion to carrying heavy stuff around if it can be avoided. However, what struck me is that this foam stuff is just pretty thin on the ground, and professional’s I’ve spoken to have done the old “suck air in through teeth whilst shaking head” response.

    Your mini review makes sense. If this stuff was anywhere near any good, it would be being used in the building and gardening industries. It’s far lighter, far smaller and quicker, all attributes which companies love, as it reduces transport costs, storage costs and, most importantly, manpower costs. Yet professional’s still give it a wide berth.

    And now I can see why. Thanks!

    So, back to the old fast setting, postcrete products. Not like they were ever that difficult to use – just pour the powder into the hole, add water and wait a few minutes – but setting posts was never the sexiest job, so anything that saved time and lifting was great.

    Anyhow, thanks for the review, you’ve saved me a great deal of wasted time, as I’m setting nine posts for a shed base this weekend.

  58. Hi Sarah, I don’t know how or why I came across your review, but found it very helpful. I’m about to do a 60ft run of fencing, and had thought about using the foam. It seems though that the hole for a 10x10cm post, should only be 15cm, any bigger and you would need more than one bag. Also, if using concrete, never put concrete on the bottom of the hole, it will form a pocket round the post, from which the water can’t drain. Thanks for saving me money.

  59. I wonder if there was a lil too much moisture in the post? You know how wood is wet when you get it, maybe let it dry out. Was the post dry?

    1. I wonder about that too. The post was dry but not “multiple weeks without rain” dry. Plus, the instructions didn’t mention anything about needing X amount of time for dry-out before use (usually when moisture is a factor, such as with an outdoor product, there is something indicated on the packaging of how long to wait, but the packaging if I recall only mentioned getting any “standing water” out of the hole, if there was any). Great suggestion either way!

  60. It’s too bad it didn’t work out for you. My posts have been up for 2 years with no problem and I love walking out of Home Dipshit with 10 bags of Sika post foam without the use of a cart.

    Your blog pops up almost right away when you try to Google info on Sika post foam, which is great advertisement for you, not so much their awesome product. Happy housing!

    1. Yeah, it’s definitely a shame that it didn’t work but I’m very glad it worked out great for you!

  61. This product is used to raise slabs under transformers for power companies as well as setting poles for power lines. Over 10,000 psi compression strength and it wont rot your 4x4s like concrete. I dig a bell shaped hole, mix the bag and pour. I also use bracing and dont do earthquake tests while it cures. West Michigan sandy soil here.

  62. I realize I am WAY late to the party but wanted to say thank you.
    I had really wanted to use this for a fence repair I need to do (7 posts just didn’t stand up over time) but I suspect I will run into similar issues, especially when running that much fence.

    Concrete and a mortar tub it is.

    Thanks again for saving me that day of frustration you spent :-)

  63. Thank you so much for this blog. I live in Nashville and spent a small fortune on a new horse fence for horses. The fence guy used the same foam on the posts and it did exactly what you described. The posts are completely unstable and can be wiggled back and forth with the slightest touch and I’m so upset. The guy came back and secured one post in concrete that the horses had knocked over and he fixed every third one on one roadside strip of fence, but all the others are weak and moving and he hasn’t been back to fix them and it’s been months. I’m beyond upset and don’t know what to do. In my experience this is a horrible product. The installer I used wasn’t a home DIY guy, he was a recommended pro fence installer and it didn’t work for him. :(

    1. That’s awful! I’m so sorry to hear that, Jennifer. There have been SO many comments on this post between people who it has worked for and people it hasn’t, and it really sucks when things that are supposed to be quicker and easier on us to install don’t work! I hope you can get him back and to fix the rest of the fence. Sending positive thoughts your way. <3

  64. Treated lumber twists itself apart. The only thing we use it for is exterior framing for decks. But we don’t use it for rail or decking. There’s other options in Georgia. I don’t care if you screw your rails and pickets on. That treated garbage will pull itself apart. It’s cheaper but that’s it.

    1. I’ve used treated wood for all sorts of projects and am very happy with the results, including my floating deck. People come to this site looking for budget-friendly ideas, and budget-friendly treated wood is great for a lot of those. It’s perfectly fine to have a preference for one product over the other (and we all eventually realize what we like to use), but being cost effective is a benefit that a lot of DIYers appreciate, so you don’t have to be such a snot about it. I can delete your comments just the same as I approved them if you continue on.

  65. Glad I came across your blog. I have two fence post I need to replace, came across this stuff on the Lowe’s website and thought maybe it would be good to try. Thought I might get my repairs done faster. Decided to stick with good old concrete. Dogs will just have to stay in the house a little longer :) Thanks!!!

  66. I just tried this product for the first time and had the EXACT SAME EXPERIENCE. The foam basically expanded away from the post leaving large visible voids on all sides. Totally disappointed. Like you said, a good learning experience but I too will be sticking with good ol’ concrete from now on. Never had a problem with it, so why fix what isn’t broken?

    Now I’m just unsure of how to proceed. Remove and replace with concrete as you did. Or double-down and buy another bag and try to fill in the big void.

  67. Yaay! Great article. I have a honey to do project and have ten post all ready at attention :P for fill. I have clay and while I think this is a great product it’s a bit pricey for me.
    Someone mentioned gravel to allow water to flow through the rocks. So meh, the never ending debate of concrete vs gravel. Never get into it. Just like this speaker wire made of pure silver produces better audio quality than copper…sheesh.
    Cheers!

  68. Great Article. Thanks for sharing. I think I’m having a different issue than yours.
    I poured the Sika liquid directly on to the post on the way down as specified. It adhered to the pole perfectly. All the posts are very tight to the foam base and will not move inside of it. BUT the problem is, the entire foam base moves in the hole a little, which means the post/base can wobble. I’m hoping the ground will settle in around it and tighten up but I’m not sure. I know with concrete, it’s so heavy that it will force it’s way outward before filling the hole upward, much more than the foam will – the foam will stop pushing laterally and move upwards as soon as it touches the sides of the hole, applying little pressure into the soil. Do you have any experience with this issue? The hole is 1/3 the length of the post as required.

    1. I had wobbling with mine too. To date, I’ve never tried to use the expanding foam after this attempt (I went back to using concrete, and this post was originally written in 2017). Sorry to hear that you had wobbling as well!

  69. You should know that power and telephone companies have been using foam to secure their poles for some 15 years now. You can imagine how much stress those poles undergo year after year, decade after decade. Just sayin.’

    In the youtube videos where it DID work, they first leveled and secured the posts with 2x4s, THEN added the foam and left it alone.

    I plan on using foam for my vinyl fence posts, and also, where they recommend strengthening the post with either a metal stiffener or filling it with concrete, I plan to pour foam inside instead. Seems ideal for that.

    1. I addressed it already: the product they use could be an entirely different product (that either works better or could require “pro” versus “beginner” expertise that wasn’t included in the instructions) vs the item sold to homeowners in big box stores. Also, since I’ve been able to secure fence posts using quickset concrete without securing with 2x4s first, I would consider that an added step to using foam, so that’s a negative IMO when comparing the two products (labeling the product as quicker/easier to use yet requiring one or more extra steps). I think it’s great you’re still going to try it, but I’ll stick to what has been more reliable/fool-proof for me to use and isn’t as expensive.

  70. Looks like this is still pretty active! Agree that different conditions likely contributed. That said, I’m not 100% sold on this stuff. I’ve heard linemen (power post installers) say they use a similar product for setting power poles, but I dunno. This stuff just doesn’t make me as confident as good ole’ concrete. Any chance you’ve had another go with this stuff since 17?

    1. Hi Jason! I haven’t given it another try. Enough people commented they’d had similar experiences that I knew I wasn’t alone, and I think there’s a chance the “pro” stuff is better performing (just speculation since I know there are industrial applications). When it comes to trying a product and it not working to my expectations, with the amount of work I do outdoors (which is a lot), it’s more about time; I know there’s a reliable alternative that is easier on my wallet and doesn’t have the shortcomings that this did (concrete). In the same exact conditions, concrete worked just fine and I could move on to the next project, so that’s great for me. I think for the cost/time/prep work that some have commented about, good ol’ concrete as you put it is nice and reliable and cheaper. Sure, it’s heavier, but I need the workout anyway, ha! Just my two cents!

  71. You lost me when you used the SJW term “mansplaining” … you sound like another tired “feminist” with no patience that needs a special vocabulary when trying to cope with normal conversation.

    1. /s Oh no. Whatever shall I do without your approval and air quotes of words that are in the dictionary. I’m totally crushed. ?

      Good luck with whatever’s making you so angry.

  72. Installed 10 posts with this product 9 months ago. Fence survived harsh Canadian winter with no issues.

    Going to install another 27 posts with this foam. Concrete is too heavy :)

  73. We live near Knoxville, Tennessee. We just used the Sika foam to set 80+ post for a 4-slat fence. We chose it because the neighboring horse farm used it on a fence they installed. While the posts did have a bit of ‘give’ to them, once they were all attached to each other with ge slats, the entire fence is very solid. The horse farm (currently 45 horses) has had no issue with fence holding up against the horses. His horses regularly push against the fence reaching over to get taller grass from the other side. As you stated, there are a number of variables which have the possibly of affecting how this product works, but for our needs, this was a good product.

  74. I think you are right on with both your adventurous spirit to try new things and your point about going with what you like and what’s easiest for you. Why make it harder? Especially if you’re doing it partly for fun! A few years ago I used the big box store version of the foam – both parts in one bag you mix, not the gallon jugs version – to help me repair some outdoor stairs. I didn’t like it much, but I didn’t hate it. I just didn’t get what was the big deal about it. It did okay overwintering, and then we moved half-way across the country to a totally different climate and I set about building a privacy fence. Because I was enclosing a large area away from the house without easy access to water, I decided to try the foam again, but this time found a supplier that would send me a bunch of gallon jugs. I was a slow poke about getting all the posts up, so I had different weather conditions for different parts of the fence. In my limited experience of about 50 posts, the temp and moisture conditions made a really big difference. I ended up liking the foam more than concrete (especially because I didn’t have to haul quikrete and water!), but you are very right about it taking a little experimentation to get used to it. After the stairs experience, if I had one or two posts to repair, I would never have gone with the foam. Now, though, I’d definitely use the foam for everything.

    1. Thank you so much for weighing in on this, Ross! I may even add your comment into the post (since there are now so many comments on this post of varying experiences, yours seems especially helpful because of the different conditions). Much appreciated for taking the time to weigh in!

  75. Very glad I stopped by here first – and then also glad I found a video (from April 2020). This gentlemen experimented with the foam and I was dissuaded. Anyway, thanks!

  76. I used Sika Post Fix this past weekend with an interesting twist. I bought 4 bags – 2 for each hole. I mixed and pour two into one hole and let it sit for the two hours…worked ok, it was stable enough for what I needed for; however the second hole, a terrible wobbly mess that I must chip out. I am a General Contractor and always use concrete (premixed before placing in the hole), I will without a doubt go back to concrete and never use this product again.

    1. Bummer that it didn’t work for you either, Ryan! Even though it didn’t work for me, I still wish it worked for others because it is pricier than concrete (and I hate wasting money on products like that, thus the whole reason I wrote this post… to hopefully spare folks some $!). I’m with ya 100% on using concrete moving forward!

  77. LOL, this is a lot like Reddit – you learn as much from the comments as you do from the post!

    In that spirit, I just wanted to comment that this post affected my decision to use some of this foam on a fence project. I am in a wait-and-see mode as I decided to use both concrete and Fast2k Backfill foam. It needed 50, 50lb bags of concrete, and 45 bags of foam. I did concrete on the corners and where the gates would go, because I read this blog and didn’t trust the stuff for pure strength. And the foam on all the in-betweens.
    As for the foam posts, I think I made my holes too wide, (I used a 12″ auger – about 36″ deep) but thankfully, the ground was pure clay so it has literally no give. I think I’m going to get away with it. But if you have soft sandy soil, you really need to follow some guidelines for it to work well – or at all.
    If you’re still reading these, I want to offer a couple tips for people who want to try this foam stuff – from what I’ve learned from the sika foam people whom I talked to. Once you get the hang of it, it is super easy compared to the concrete. So without further ado:

    1: DEPTH is key – not width. You need 36″ of post depth for a post that will top out at 6′. 48″ for an 8 foot post. Basically, 1/3 of your post should be underground.
    2: WIDTH should be narrow – unlike concrete where you are making a heavy-ass upside-down lolipop, relying on the weight of the cement to hold it in place, you are basically adhering the post into the soil as if the soil had never been removed. They recommend 6″ or 8″ holes for a 4×4 post. You could never get away with that with concrete.
    3: WATER – its bad. At least when setting the stuff. It won’t adhere to water and it may affect the chemical reaction. So you need to sop up (re: bury) or remove standing water from the hole. But once it sets up, it should be totally impervious.
    4: VERTICALITY: The post hole should be very true with smooth edges. If its rough or strangely shaped the foam won’t evenly apply pressure to the post from the hole edges.
    5: POST SUPPORT – have your posts set plumb with some batting boards or stakes screwed in so they don’t twist as the foam cures. You won’t have time or want to be trying to level it with a level while its hardening as you work.

    Some other tidbits:
    To address a different, much more scathing review: the bags do NOT have a popping bag inside (like a chemical ice pack does) if you “pop” the bag, you will pop the bag. And you will rue the day.
    Fast mix – The “Shoeshine” motion is to scrape the stuff off the inside of the bag and swoosh it into the other side. Do it quickly exactly like a shoeshine. Concentrate on scraping the goo off the inside of the bag side to side, then flip the bag after about 15 seconds and do it from that side. I found I could get about 20-30 swooshes on each side in 30 seconds.
    The Two sides are separated by a chip-clip thing, that’s what keeps the compounds separate, not a separate blister bag inside. Do NOT pop the bag. (worth repeating)
    Keep it inside your house until you use it. It can be used in almost any temperature but the substance itself needs to be like room temperature when you mix and pour. Cold (or maybe even extreme hot) makes it cure poorly, and slower, or not at all? Your garage floor is too cold.
    Use the gloves! But have them ready to put on immediately after mixing – like, already pre-opened. They are too slippery to hold the bag well while mixing, but are like those grocery produce bags that take a few seconds to get open. If you are licking your fingers and fiddling to get your gloves open as you see the bag expanding, you might be about to have a bad day. You absolutely do not want this stuff on your fingers, let alone all over the place if it explodes. (You would probably have to wait a couple minutes for that to happen, but why press your luck?) The stuff is sticky like cartoon glue.
    Have a crappy pair of scissors right next to the hole. If the tear-of tabs fail, or if you want a little precision with your pour like an icing bag just snip a corner rather than tearing off the whole top.

    Hope that helps if anyone is still thinking about using this stuff. Depending on your situation, it could be a real back saver. And with what mess it does make, its still way cleaner than concrete dust. Cheers!

    1. Thanks so much for your in-depth info on your experience! I’m sure others will find this very helpful. :)

  78. Great job trying something new! I’ve been building fences all year using this stuff and if there is anyone on here, like I was, looking to see if foam is a viable option – no offense to the UDH – but don’t be completely discouraged by this experience. Sarah identified one reason it might not have worked (soil) but from the photos there are a couple other observations that contributed to this foam fail:
    Hole too wide: Foam likes a 8″ hole around a 4×4 post – it needs to be TIGHT. The foam squeezes and adheres from the sides of the hole. Think about pushing on a door frame with your hands – if its 3 feet you’re very strong, but at 5 feet you barely have any leverage and 6 feet, you might not even be able to reach. Hole needs to be narrow – its counterintuitive to concrete work, where more = more stability.
    Hole too shallow: Ideally put 1/3 of the post underground. Absolute minumum of two feet – provided the hole is narrow and clean.
    Hole dug with shovel: Can’t do it. You can’t get a clean enough, narrow enough or deep enough hole with a shovel – you need a posthole digger or an auger (use a 6″ auger bit to acheive an 8″ hole). You want a cylindrical hole so the foam presses evenly, if its all akimbo the foam will not press evenly from all sides and the post could fail or move during setting.
    Sandy, loose soil: which is the reason the post hole needs to be clean, narrow and deep. Good trick for digging out sandy soil is to pour water in the hole as you are digging to make the sand stick to the posthole digger, otehrwise you can’t remove it (it just slides through the jaws). Just make sure all standing water is removed from the hole before adding foam – otherwise it makes a soft styrofoam.

    If you can dig a deep, narrow, clean hole to drop a post at least 2 feet deep (3 is better) then foam is a great, great option that will save you a ton of time and mess. Just make sure to use gloves and mix the stuff near the hole! Good luck, I’ve used Sika, Fast 2K and Secure Set and they all do great in the right conditions!

  79. Loved your post. Very informative and well written.

    There are many variables that could have contributed to the failure of the foam. Your photos were perfect in showing what really happened in your case. Don’t think I would trust it for a gate post. Too much constant movement opening & closing. But, that’s just my opinion. I’ve not tried it, you have. I appreciate you sharing your experiences.

    I just stumbled upon this post and I’m impressed with your many different projects. I will be following you in the future (if I can figure out how. I’m not very tech savvy). I look forward to seeing all of your projects.

    1. Hi Brenda! One of the easiest ways of staying up to date on my posts is to subscribe to my newsletter. Just enter your email address in the subscribe box you see on the page and confirm that you want to be subscribed: UglyDucklingHouse.com/Subscribe

  80. I replaced my fence 2 years ago using the foaming product and so far it has held up. There is a bit more play at the post than when using concrete. I also still used concrete at corner posts and at gate posts. When doing my daughter’s fence, I also used concrete in a couple of the posts in the middle of the run. This may be my own “just in case” fail safe measure.

    I would say that I am 70% sold on it. I believe you should take extra care when using it as well as, with any project, evaluating each situation separately.

  81. I’m a fencer, found this site while looking into whether this stuff was worth trying out over the normal quick cure postmix I usually use (good SEO btw). I was sceptical looking at the advertising, and having read your experience makes me think it’s nowhere near reliable enough for professional use (I was thinking about trying to find a bulk source if it was any good, for cheaper pricing, after testing in my own garden of course). I’m still curious and perhaps might still buy a pack to test out, but I don’t have high hopes, imagine not having to go and collect half a ton of postmix and then lug it all to each hole… Ah we can dream!

    I read a couple of comments and just thought that perhaps I could clear up some misconceptions people have (having installed thousands of fence posts myself, in all different conditions and for all sorts of different use cases):

    As a general rule, if you’re putting in a post that’ll be 6ft out of the ground your hole should be 2ft deep, take into consideration ground conditions and what sort of stress the post (and surrounding soil) will be under, if the ground is almost always rock solid, then you’ll probably get away with a little less deep (again, general rule of thumb), if the ground is soft, then ideally you’d go deeper.

    If you’re hanging a gate, then go deeper, a gate gets lent on, has force put on it from all different directions, get’s slammed and is only braced for added support on one side (usually), how deep you go depends on the weight of the gate, how often it’s used and what ground conditions are like, but the deeper the better.

    One final tip when using quick cure concrete: Tamp it in! Use a fairly thin piece of metal or wood (around an inch across ideally) and after you’ve added the water (which despite the instructions I always add after adding about half a bag, before adding the other half, as different holes will require differing amount of water to properly mix with the concrete) keep jabbing at it until you feel it become more solid. You need to work your way around the entire post, all the while holding levels (ideally a single post level) and keeping the post true. This helps the water mix with the concrete, as well as removing voids from it. Leaving voids, especially next to the post isn’t good, in areas where ground frost occurs it can crack the concrete, and this will likely get worse every winter. In areas with plenty of rainfall this creates a pocket of moisture which will encourage the post to rot and entice insects to congregate there.

    1. Thanks for the comment! Glad I could help in any way to give you the info you needed to make the decision. Lots of great info in your comment, too. For anyone else reading all these comments: when I went back to using concrete, that kind of ended things right there; I never wound up having to make another change because in all of the years since I tried this experiment, it has remained a solid and sturdy gate.

  82. Did you prime the post first? I don’t think I read this, my apologies if you did say it, but you’re supposed to pour the foam onto the base of the post and get a good coating all around and then finish filling in the hole. If you don’t do that then the foam likely won’t adhere to the entire post.