I believe they are. I use a dimmer and they work great

🚨🚨🚨NEVER STICK YOUR HAND UNDER THE SLAB, in case something slips or snaps!!🚨🚨🚨

@@sambrusco672 lol. Yep. Should be obvious but that’s good advice. You use a hammer or pole to shove the rocks in too.

@@sambrusco672 🤦‍♂️🤦‍♂️🤦‍♂️

You let down the jacks a little at a time (both simultaneously), then there will be no tension on the C-clamps. The C-clamps are tightened around the concrete slab.

It's what I had on hand and so far it seems to work fine.

You can easily cut off the excess polyurethane after it cures.

I agree! With that said, I have a LOT of rigid foam scraps that I will use as loose fill, THEN I’ll use Great Stuff to fill the gaps and bind it all together. Great Stuff gets expensive real fast! 🚨🚨🚨NEVER STICK YOUR HAND UNDER THE SLAB, in case something slips or snaps!!🚨🚨🚨

Backer rod and caulk in the expansion joint. This will allow for movement and keep the water out.

How's it holding up now that it's been 4 years?

Absolutely correct. This guy needs to give credit where credit is due.

@@ke0nc hack job john.

Skip that - you want to cram a bunch of sand or gravel. The pink foam is good if you are doing a new pour of say an insulated slab - where you pack out a base of sand/gravel, then lay that on top and then pour it. However there is no way to get that stuff in there supported evenly. What you can do is cram sand up under it and use the end of a 1x1 to pack/press slightly moistened sand into it. Pour some sand and pack, pour some more and pack. Once the hole is basically fully filled get out your sledge and swing it down in the whole you cut to pack that sand even tighter. Then proceed to fill in the hole around it and pack down. The foam will work fine until it doesn't and because you haven't repacked the cavity water will run down around that foam and flush the supporting soils.

@@bryceg5709 I haven’t seen any reports of Great Stuff or rigid foam board failing. Have you tried it and it didn’t work for you? Both will support >25 psi (3600 psf) that’s less than any passenger vehicle and the concrete rolling over it. The other big advantage of Great Stuff is that it expands, so you don’t need to get out the sledge hammer.

You dont put dowels in sidewalk. That's why there are tooling lines every 4 or 5 feet. Sidewalks are above the frost line and are always susceptible to the movement from freezing and thawing. Sometimes sidewalk will get mesh installed pre pour but not usually. If you put dowels in 4" of concrete that's on ground that freezes and thaws multiple times a winter it's going to be busted to shit after one season sir.

A 3 tons farmers jack is $60

@@beaujoe69 where do you buy the eye bolts. and how many pounds are they rated.

@@beaujoe69 you can use a scissor jack for cars - you probably already have more than one in your family. You will be using TWO of them, and they are intended to lift a car. 🚨🚨🚨NEVER STICK YOUR HAND UNDER THE SLAB, in case something slips or snaps!!🚨🚨🚨

It looks like you did this in 2019. It is now June 2022. How is it? If it settled, it’s because you used the rigid foam board and not GREAT STUFF. The board must have left gaps and the earth shifted around under the slab.

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