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Foam injection repair: how does it work?

Updated: Mar 26

So, you’ve got a quote and they suggested polyfoam injections to fix your concrete. What does that even mean?! No need to worry! Here’s everything you need to know about it (and whether or not you should use it at home).

What are polyfoam injections?

Polyfoam is short for “polyurethane foam”, a chemical compound that is liquid but then it expands and dries into a solid, very strong foam.

Because it starts in liquid form, polyurethane can be injected and perfectly fills cramped, hard-to-reach spots underneath pool decks, foundations or sidewalks. And to seal it off (ha!) polyfoam is environmentally inert, meaning after application it isn’t dangerous to the environment, pets and humans.


Polyfoam injections can be used just about anywhere with these conditions: it supports, it levels up, it’s flame-retardant and water-resistant, meaning ADP polyfoam injections can even fix concrete near water without issues.


Benefits of using foam injection

Polyurethane truly is the best, fastest way of leveling concrete around the home. APD recommends using polyfoam to most of our clients because:

It’s cheaper:

Tearing up and redoing your sidewalks or pool deck can be very expensive, and the natural erosion process means new concrete can still sink eventually. Instead of tearing up your slab, polyfoam injection lets you keep using perfectly good concrete and fix sunken spots.


Foam is lightweight:

The main reason why concrete sinks and sidewalks start wobbling is because the soil underneath is weakened by erosion, compacted or settled. Polyfoam adds strength and stability without the weight of traditional mudjacking. This means your soil won’t degrade even more.


It’s clean:

The beauty of polyfoam injections is there’s virtually no clean-up after. Just some remaining dust can be quickly cleaned up with a broom.


It’s fast:

After application, you can walk or even drive over the fixed spots in just an hour. Unlike concrete, there’s no need to wait for days until it dries!

The choice is clear: if your concrete can be fixed with foam injections, it’s the best option!

How does it work?

Polyurethane injections stabilize your concrete. Depending on your needs, APD can either use injections to level a slab or even to bind the soil to strengthen the material below smaller concrete slabs. Although the exact procedure will change depending on the goal of the project, here’s how it works:

Step 1, Evaluation:

Depending on your needs, either an expert team or an engineer will take a look at the issues to figure out what are the causes.


Step 2, Designing an action plan:

APD uses different polyurethane types depending on the weight of the structure, the stability of the soil underneath, and other factors like nearby water. At this point, APD can correctly suggest the type of polyurethane foam that best fits your needs.


Step 3, Drilling and application:

Depending on your project, this can be a fairly quick process. Our team uses poly foam injections mainly with two different purposes: to fill voids in the soil beneath your concrete, or to stabilize the slab. Filling voids means your soil has already settled and there are “holes” or air pockets that will be replaced by polyfoam. For slab stabilization, we can fill the gaps but also inject polyfoam into the ground to bind the soil together and provide better support.


Step 4, Cleanup:

This is one of the best parts of polyfoam injections: cleanup is incredibly fast! Minutes after the job is done, APD only need to sweep the slab and that’s it. The mess is minimal because the concrete is drilled then patched.


Types of poly foam for concrete repair

Our team will use specific types of polyfoam injections depending on the location of the project, your needs and the state of the concrete. But regardless of the application, APD always use polyurethane foam that is 100% environmentally safe and 100% hydrophobic, meaning water won’t affect the job.


Most of the time, APD use one of these polyfoam types:

  • HF202: This is a hydro-sensitive polyfoam designed for jobs where water or consistent moisture is present. It sets up in the presence of water and maintains stability in wet environments. It’s great for residential concrete and sinkhole repair.

  • HF202FAST: Because it has a low density and quick reaction time, this polyfoam is used it to lift smaller cement slabs. Of course, it’s also hydro-sensitive and stable in wet environments.

  • HF402: This type is hydro-sensitive as well, but denser than the HF202 types. It also sets up when water is present, and maintains remarkable stability in wet environments like pools or ponds. Our team uses it for residential, commercial and industrial foundation and concrete repair.

  • HF402FAST: This one has the same strength as the HF402, but with the speed of HF202. This type of polyfoam is used for deep foam injections that need faster reaction times, so it’s great for lifting slabs.

Sunken driveway before polyfoam injection
Before APD polyfoam injection repair

Polyfoam injections: what can you fix?

If you’ve got a foundation with minor damage, wobbly sidewalk or your concrete slab has just seen better days, polyfoam injections are probably a great idea. Polyurethane injections are successfully used for:

Foundation and sinkhole repair:

If your home is showing cracks on the walls or there are sinking spots, polyfoam may be used to provide soil stabilization and give even more support to other foundation repairs like underpinning.


Trip hazards:

Uneven concrete slabs are just accidents waiting to happen. Our team uses polyfoam to stabilize the ground under any concrete slab, level it and patch up any cracks to keep everyone safe.


Pool deck repair:

Do you have an uneven pool deck? A few deep polyfoam injections will make your deck walkable again. We use polyurethane to quickly stabilize and raise concrete slabs around your pool so it looks as good as new.


Sidewalk repair:

If your sidewalks are unstable or wobbly, you’re probably dealing with settled soil. Polyfoam can fill those voids to provide a secure base and keep your sidewalks level. APD can also fix sidewalk cracks by lifting the slab with polyfoam injections and patching it up.


Crawl space repair:

Sometimes, cracks in your walls might not be related to your foundation but to your crawl space! APD uses polyfoam to strengthen the soil below your crawl space and give more stability to your entire home.


Seawall repair:

Since we only use hydrophobic polyfoam, it’s a great option to fix seawalls that could be exposed to the elements.


We hope this info gives you a better idea of what polyfoam injections are and how they are a great tool to fix your concrete. Have you ever used this option around your home?


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