Concrete roads, sidewalks, flooring become unstable and unsettled in due course. You need to correct this or the issue can increase and turn more expensive. Concrete lifting with polyurethane foam is the best solution in comparison to slab piers, mud-jacking, and replacement.
Polyurethane foam material available in the market differs. Wrong foam usage can cause issues and cost more. So, first understand about the lifting foam before purchasing it for application.
In polyurethane foam concrete lifting method not just expansion, but even the cure times and adhesion are crucial.
Foam response time
If the polyurethane foam reacts very slowly then it is good for filling voids, but raising concrete can be a disaster. Slowly reacting material travels beneath and beyond slab area you are repairing and expand. Thus, multiple slabs get lifted with the foam bridge created beneath. For regaining control, it is necessary to cut through foam layer and try the lift again. You lose money and time.
It is obvious that when you lift slab from one side the other side lowers. When concrete slab gets raised from one side and you can rock the injected foam to level the slab. The foam needs to remain pliable for sufficient time for slab lifting and levelling. Good concrete lifting foam needs to have setup time of 15 seconds and remain supple for 15 minutes.
Many people think that 4 lb. foam needs to be used but why not save money using 2 lb. foam. A one-cubit foot box needs just 2 pounds of 2lb. to fill. You can even fill it with 4 pounds of 4 lb. to get same result. Double the amount of material means double the expense. Actual difference in both is foam density. The box has less foam and more air, while using 2 lb. polyurethane material.
The raising foam needs to elevate the concrete but must not hold on to it because it can adhere and lock adjoining slabs. Therefore, foam that sets up with tough exterior skin is needed. The skin removes adhesion to adjacent concrete slabs.
Efficient expansion rate for concrete lifting is 20-25 times original value.
Advantages of polyurethane foam method
- Cleaner process
- Less disruptive
- Swift application
- Less wait-time
- Less clean up
- Minimal labour-intensive
- Less costly
To enjoy all these benefits of polyurethane foam technique makes sure to choose the right kind of foam material.