The typical answer: “It depends.”
Foam concrete lifting, polyurethane foam concrete lifting and foam jacking all describe this repair — contractors use the terms interchangeably, and the material and method are the same.
When you make an investment in something it’s reasonable to ask, “how long is this going to last me?” We get asked all the time, “How Long does Concrete Lifting with Polyurethane Foam Jacking Last?” Quite often and the answer is “it depends.” This isn’t meant to be a dance around answering the question directly it’s just there are a lot of factors to consider when answering. Here are a few:
How Much Does It Cost To Lift Concrete With Foam?
Foam jacking is priced by the amount of material a job takes, not by the square footage of the slab. Two driveways of identical size can differ substantially in cost if one sits over a larger void than the other.
What moves the number:
Void size. The larger the space beneath the slab, the more polyurethane it takes to fill.
Lift height. Raising a slab an inch takes less material than raising it four.
Access. A slab a crew can reach easily costs less to lift than one behind a fence or inside a building.
Slab condition. A slab broken into several pieces may need more injection points, and in some cases cannot be lifted without replacement.
Against replacement, foam jacking is usually a fraction of the cost — replacement means demolition, disposal, new concrete and days before the area can take weight. Against mud jacking, foam jacking often costs more per job up front and less across the life of the repair, because it does not wash out or add weight to soil that is already moving.
What is the life of the polyurethane foam?
Polyurethane is essentially a plastic that is manufactured under your slab by combining two chemicals together via a mixing gun. Like most plastics, polyurethane is a very hardy and long lasting material. There are a few chemicals that can cause it to dissolve or breakdown, but unless your structure is built on top of a contaminated site, this shouldn’t affect you. UV light is another source that can degrade polyurethane, but since the material is being injected into an area void of sunlight, there isn’t anything to worry about. In essence, the polyurethane will last well beyond the human lifespan as long as it remains in these conditions.
What can cause the Foam Jacking to Fail?
- Improper Drainage: If you have poor drainage that is continually degrading the soil around the slab, polyurethane foam jacking can only do so much. You need to make sure you address any drainage issues along with having the foam jacking service.
- Weak or Highly Saturated Soils: If the deep soils are weak or highly saturated, there is a chance that the soils may compress or settle. With the weight of the slab and the weight on top of it, the slab may settle again. To avoid this, a process called deep soil injection can be used, whereby the foam jacking contractor address your weak soils by injecting the polyurethane in a gridded pattern at multiple depths. This will densify and compact your soils at depth and should prevent future settlement. This process is so effective that it may be used to increase the load-bearing capacity of your slab to repurpose it to support heavier loads.
- Adding Overly Heavy loads to the Concrete Slab: Concrete Slabs are designed to carry specific weight load ranges. If the weight is overcome, then there is risk of the slab cracking or settling. The purpose of foam jacking is really to stabilize your soils, reestablish the load of your concrete slab back into the soil, and to provide lifting via expansion and densification. Polyurethane can be used to allow your concrete slab to bear more weight, but this is a different process than typical foam jacking.
So How Long does Concrete Lifting with Polyurethane Foam Jacking Last?
In the right conditions, Polyurethane Foam Jacking can last lifetimes. When approaching your project it’s important to address the issues that could cause the life of the polyurethane foam jacking process to diminish.
We recommend you find the right contractor to help balance longevity, costs, and to make sure your project is completed to your satisfaction.