FAQ about polyurethane injection
Why does concrete slant and crack?
In a nutshell, uneven settlement of the slab. But there are many reasons why this can happen. It could be that the soil was not properly compacted before the concrete was poured, but even with proper compacting, problems can appear quickly due to the weight of the slab. Then there’s the freeze-thaw cycle of winter, which makes concrete expand and contract, potentially causing it to resettle in a slightly different position after a thaw. Summer presents another expand-contract challenge, this time with soil. On hot ‘n dry days, the clay soil we have here in Kansas and Missouri shrinks from lack of moisture, and the concrete settles a little bit. Then when it rains, the clay sucks it in and expands, pushing the slab back up. Other potential causes include heavy traffic, machinery vibrations, animal tunneling, and water erosion. And remember, when it comes to concrete slabs, WATER IS YOUR ENEMY! You want to keep drainage as far away from your foundations as possible, and one of the key things we look to accomplish while raising your patio or walkway is ensuring that water will flow away from your home or business.
Can you lift a slab outside in the wintertime?
Absolutely, in our region you can. This winter, there were about 10 days that were too cold to lift outdoors. In extreme cold, I will blanket your slab for a day or two to warm up the ground under the concrete before we lift. The reaction of the poly underneath the slab will quickly rise to 220 degrees once the work begins.
Is your 2 year warranty transferable to the next homeowner if we sell?
Yes, it is transferable. When your address is entered into our system for a future inquiry to us, the history of the work at that property will appear, regardless of the name of that homeowner. Inquire about a certificate of warranty if you would like one for your file.
Can my driveway or sidewalk float away if it floods really bad with a bunch of foam under it?
No, your concrete won’t be buoyant at all. This has been proven all over the country. An injected driveway or sidewalk has never popped out and floated away. Concrete is ridiculously heavy, and therefore it would take a ridiculous amount of foam to make it buoyant at all.
Will small animals eat the foam and nest in there?
Rats or mice will not take a substantial bite out of our finished foam. We do recommend that you back-fill with topsoil when the concrete is raised to the level that foam is showing. A mouse will take a crack at any exposed foam, but it is a hard product. Finished and cured poly is closer to the density of a plastic cup than to a piece of styrofoam.
How long will we have to wait before we drive over the repair?
15 minutes is all it takes for my most common poly product to accept heavy use. The fast cure of polyurethane foam has made it a go-to repair for straightening railway tracks, highway and airport runway leveling, and industrial floor and machine leveling work. I can repair a factory floor between shifts, and they are driving forklifts over it after 15 minutes.
I have cracks in my sheetrock on the inside of my house around the doorways. Can this fix that?
Cracks like that are generally caused by foundation problems, and you should give us a call. I have 20+ years of home building experience, and I’m a specialist in residential home framing and foundation. I have the tools and will give you the time to get to the bottom of the problem.
A tree’s roots are pushing the sidewalk up. Can you fix that?
I can make it look much better, and safer. However, we cannot offer a warranty on the repair. Once this starts to happen, those roots will only get larger, so the movement will continue as long as that tree is there. If the damage is ancient, though, the tree may be done giving effort there to growth by now. I can float your sidewalk over those roots so the tripping hazards are gone. Your tree will not be harmed by the polyurethane. Note that backfilling of the concrete will almost always need to be done with this type of repair.
Is poly lifting harmful to me or the environment?
Our polyurethane foam is non-toxic and our method is the greenest way to level concrete. The polyurethane foam we use, by HMI, is made of 40% recycled materials, giving it the smallest carbon footprint in the poly foam industry. PLUS lifting existing concrete eliminates the need for new concrete, a large contributor to greenhouse gas emissions.