Maybe you’ve seen internet videos and posts where DIYers inject canned spray foam under their settled slabs, or maybe you thought up the idea on your own. However you got here, you’d probably like to know: Will canned spray foam lift concrete?
While professional concrete leveling services usually yield a better (and safer!) result, technically you can lift concrete with canned foam.
Here at A-1 Concrete Leveling, we’ve been lifting concrete professionally for 30+ years, and while we don’t recommend lifting concrete with foam as a DIY project due to the many risks involved, we know that it’s possible, and many people would like to know about it.
For this reason, we’ve compiled some of the different DIY techniques out there so you can get to know what’s involved in the DIY foam concrete lifting process. We’ve also included the risks and potential dangers of doing this type of project yourself.
While we recommend against the DIY approach when it comes to foam leveling (more on the risks next), it is possible. Here are some popular DIY methods we’ve found around the internet:
Drill and Fill
In FriendnFamily’s video, they simply drill holes in the concrete, then put the nozzle into the holes and inject the foam under the slab. It slowly lifts, although it does not become perfectly even with the neighboring slab. Notice how it lifts both the sunken and raised slab at the same time.
Jack the Slab
In Jack of All Trades’s video, he first builds a lifting device that he drills into the concrete to serve as leverage and a spot to jack the concrete up.
Once it’s jacked up, he drills holes in the slab and injects the foam below. After a couple of hours, he cleans off the excess foam and fills the holes and expansion joints.
If you look closely, he actually over-lifted the slab. This is because he got it level with the jack, then put expanding foam under it, which lifted it further.
Chains and Bottle Jacks
In a slightly more complicated approach, Everyday Home Repairs shows us how he attaches C-clamps to his walkway slab, then uses bottle jacks and 4x4 posts chained to the C-clamps to lift the slab.
Once suspended, he drills holes in the slab and injects canned spray foam into the voids, then seals off the holes and expansion joint.
This ended up being the best repair of the three. We did notice, however, that he avoided lifting the drop at the brick step, which looked to be down about a 1/2” or so. This would have been the more complicated part of this lift, so it was probably best to avoid it.
When lifting concrete slabs as a DIY with canned spray foam, there are quite a few potential risks to keep in mind:
Lifting the slabs with jacks, drilling in the wrong spot, or applying pressure in the wrong place can all easily cause the slab to crack. This can make it harder to lift, even for professionals, and means more money to repair the new cracks.
Slabs Can Get Stuck
When lifting concrete, professionals often have to cut the slabs with concrete saws as they get stuck on each other. This important step can be difficult to do as a DIYer, but it's crucial to prevent cracking due to the building pressure as the foam expands underneath.
Professional foam designed specifically for lifting concrete is not strong enough to support heavy loads or vehicle traffic. Canned spray foam is not designed for use under heavy concrete slabs and will likely be able to support even less weight and pressure.
Uneven Void Fill
It can be hard to fill all voids underneath a slab with professional foam concrete leveling – the injection can create “pancake stacks” of material. Canned spray foam is likely worse as the foam and injection device is not designed for use under concrete.
Mess and Staining
Chemical expanding foams can get stuck to the concrete and be very hard to clean off. When left on, they can yellow with sun exposure. It’s hard to control where and how much these foams expand, especially when using a can of foam.
Heavy and Dangerous
Lifting heavy slabs or suspending them in the air with jacks and wooden planks can be risky for your safety. If attempting foam concrete lifting as a DIY, wear safety equipment, like gloves and goggles, and be aware of where your fingers, toes, and feet are at all times.
If you attempt DIY concrete leveling of any sort, there’s a chance that you can damage the slab further. Not only will this additional damage be more expensive to repair, but it may also make it impossible to level the concrete properly.
Once the concrete slab is lifted, there’s no going back. Even for professionals, over-lifting the slab is a possibility, especially when using foam – although experience and training can help avoid this. With the DIY approach, it’s easy to inject too much foam under the slab and raise it too far up.
If you’re not sure whether or not DIY is the right approach when it comes to lifting your concrete, here are some alternatives to consider:
Professional Concrete Leveling
Having your concrete lifted by professionals is the safest and easiest way to go about raising settled slabs. It’s usually done within a few hours, can last for the life of your concrete itself, and can save up to 70% off the cost of replacement.
Grinding the high parts of the concrete down can be a cheap and easy fix for trip hazards, although it can leave the concrete thin and weak. It’s a good option if you know you’ll be replacing the concrete sometime in the near future.
Additional Concrete or Patching
Adding more concrete or a patching compound on the uneven concrete to eliminate the trip hazard can work as a temporary solution. While it may even out the trip hazards for a little while, it will likely end up cracking or crumbling away as the original concrete expands and contracts naturally.
If you’re dealing with severely cracked, crumbling concrete, it may be best to replace it altogether rather than try to lift it up. This is a more expensive route, but it does come with the benefit of allowing you to switch up the design or functionality of the concrete.
Due to the risks associated with concrete lifting foam DIYs, it’s not something we recommend doing on your own.
However, that doesn’t mean that it’s impossible. As you saw in the YouTube videos above, it works out successfully for some DIYers.
If you do decide to lift your concrete yourself with foam (or any other material), be sure to keep safety as the number one priority by wearing gloves and goggles, and by keeping fingers and toes out of the way of the moving slabs.
But if you’d rather leave the concrete lifting to the pros, we’ve got your back.
Here at A-1 Concrete Leveling, we provide foam concrete leveling in many of our nationwide locations and stone slurry grout leveling in all. Click the link below to request a free onsite cost estimate with a member of the A-1 team near you!