How To Fix A Sunken Sidewalk With Spray Foam

It might come as a surprise but you can actually use a standard can of Great Stuff spray foam to support a sidewalk that has settled over the years. This can be a quick fix if replacing this section of sidewalk with new concrete isn't in your plans/budget.

Supplies Used

Free Home Maintenance Checklist:

Chapters
0:00 Intro
0:20 Drilling Holes For Spray Foam
1:21 Lifting The Sidewalk
3:14 Filling In Void With Spray Foam
4:38 Cleaning And Sealing Concrete Section

DISCLAIMER: This video and description contain affiliate links, which means that if you click on one of the product links, I’ll receive a small commission.

[ScottMosley]

As a concrete and foundation inspector employed by a company specializing in poly foam lifting and leveling, I can attest that this method is highly effective. One crucial step not to overlook is the curing time. While commercial-grade poly can solidify in 15 minutes or less, as mentioned in the video, Great Stuff will require a longer curing period. Excellent video, my friend!

[theflash]

With all due respect to your ingenuity, which I applaud, I had this exact problem, but had a much easier - and cheaper - solution. I grabbed my neighbor, and together, we struggled up the broken off, but intact, 4'x2' slab until it was resting on its edge. I then shoveled the requisite amount of dirt onto the area, then struggled the slab back down to slightly above level, allowing for compacting of the new dirt. Less than an hour, no jacks, no support beams, no chains, no j-hooks, or drill needed, and didn't spend $16 on spray foam. That was over a year ago, and the slab has now settled to level.

[johnnelson]

We had a company come out and do the same thing, but if I was to do it again, I wouldn't let them drill the holes because we got a few cracks now between a couple of the holes. When I was a kid we'd use a breaker bar and just lift the sidewalk and put dirt under it and then put it back down. I think overall, that is the better option and no drilling holes in the cement and trying to match the color later

[williambranham]

Well thought out and executed. You’ll probably get comments about easier and less costly ways but remember this you made a clear and clean video.
Thank you!

[Tony_in_AZ]

Thanks for simple, to the point video. You do not talk about your puppies, neighbors or other unnecessary items.

[jochetaman]

I love your communications skills, the way you talk throughout the activity is key. Excellent brother !

[runthenumbers]

I like that you showed your lifting rig before you made it. It's nice to see what's being made before you make it rather than spending half the demonstration wandering what's being demonstrated.

Other youtubers should use this format :)

[ddwieland]

The most valuable part of this demonstration to me was the use of C clamps, jacks and timbers. Raising the slab with such control allows the use of a variety of fill-in support methods.
The tip about drilling concrete with a rotary hammer is valuable too; I learned that after struggling with a simple hammer drill.

[ContantContact]

I did something like this about 5 years ago. I had to raise a pad in front of a two step porch/entry. I did all I could to raise it, tracktor & loader, crowbars (big ones), and more. Got it to about right, close as I could get it and stuff all I could under it, including several cans of foam.
I also repaired two broken step corners with a concrete mix and forms. It was pretty good, but didn't match. No one complained but I wanted more.
So I got some of that polymer resurfacer and did it all plus the 40 ft of sidewalk.
All looks great now. And I made the polymer a bit thicker to get the rest of the leveling I couldn't get before. This was a 60 year old sidewalk and step.

[CrucialArmitage]

Great video. I was really excited when the slab got caught on the rock building pressure and then releasing with a sudden movement. I could not help but think that this was a great analogy of how some earthquakes happen.

[davidscottkrause]

I paid a concrete leveling company to do this in 15 minutes for $300, but they didn't use spray foam. After they left, I poured dry sand all around the sidewalk section to fill the gaps and packed the soil in, so it can't happen again. I am impressed you were able to do it yourself.

[yeeeehaaawbuddy]

I have no issues like this to repair, however I did want to leave a comment because you did a great job of explaining things in a direct manner. Much appreciated!!

[jasongerken]

I have done this and it works very well, although I didn't use the jacks, I simply raised the sidewalk slabs with the Great Stuff foam. It will expand and raise the slab on its own, but be careful not to inject too much, because then it could end up being too high.

The only thing I would recommend is to save the concrete dust from drilling the holes. Then you can put that on top of the caulk that you put in the holes so it blends perfectly with the existing sidewalk and the holes won't show.

[grdvd]

Very smart! But if crappy or suspect walkway, suggest scrap of wood (at least 3/4" ply) under each bottle-jack to distribute load… avoid cracking and another project 😀

[kenlee]

Anyone concerned the foam might get compressed over time. There is another product made by Loctite called Tite foam. It is advertised as being 4 times as dense as other expanding foams. It has been a long time since I purchased it but it should be comparably priced as other foams and available at many of the same stores.

[hartleyhubbard]

Great demonstration of how to resolve this issue - i know alot of residents have these trip hazards. A final addition to your presentation, is to work out the math on a white board, to show the cost of "remove & replace" verses "lift & support". It was great to watch this. Greg (garden grove, CA)

[nv]

Great video. We had enough issues that we had sections aligned by a company that pretty much did the same thing. Although I wonder if the foam was the same or less susceptible to long term degradation.
You also covered a key thing about dealing the joints, prime point of water entry under the slabs. I used backer rod with Seka sealant, both regular and self leveling, for this. I also lightly spread sand into the sealant while wet, then brushed excess away after fully cured. Makes for a nice appearance.

[gravitymediapro]

Did anyone else think it was just going to take the spray foam to accomplish this? Asking for a friend.

[tsjuno]

I did mine differently. I clamped angle iron on the adjacent slab and left the overhang over the slab that I raised. Used this a a stop so it can only be raised to the same level. I used an air hose and a piece of pvc to blow out a few channels under the slab. Simply added foam in the void. It lifted the slab until it hit the angle iron and then the excess simply flowed out the sides. No holes. No jacks.

[sdexcalibur]

This is gold, My company does poly level and can lift and support sunken in walkways, driveways, roads ect but it is costly.