Sunken concrete is a subject of worry. Mudjacking and polyurethane concrete raising are two methods applied to raise and support the unstable slab. Holes are drilled and material is pumped beneath the concrete slab.
How polyurethane concrete raising method works?
- Concrete slab is raised, voids are filled and soil gets stabilized.
- 5/8” hole gets drilled through slab into subgrade.
- Tapered delivery port gets installed in this hole.
- Air-purged injection gun gets connected to this delivery port.
- Polyurethane material is delivered through the injection gun beneath the slab.
- Material starts to expand in seconds, soil gets compressed and concrete gets raised.
Polyurethane foam concrete lifting process accompanies multiple advantages in comparison to other ancient technique like mudjacking.
Reasons why polyurethane concrete raising is better
Fast cure time – Total load time for sidewalk, driveway, or concrete slab occurs in just 15 minutes, after foam injection and there is no wait of 24 hours.
Small injection holes – 5/8” holes versus 1”-2” holes. Difference is clearly visible. Patching is less visible in polyurethane foam raising process.
Waterproof – Polyurethane foam comprises of high density close cell nature and does not allow water to penetrate. It is a stable material, especially for wet conditions. It does not get washed away or percolate damaging materials in the soil.
Expanding property – Polyurethane foam can be spread in voids as tiny as 1/32th inch. It expands fifteen times its initial capacity. Thus tiniest voids under driveways or concrete slabs can be filled efficiently.
Lightweight – Foam material weighs just 2 pounds/cubic foot in comparison to 100 pounds/cubic foot of average mudjacking material. Mudjacking slurry can deteriorate the soil beneath the slab overtime and the issue reoccurs. Polyurethane foam has high lifting abilities and supports considerable loads in due course.
What to consider while buying foam?
Foams are not created equally. Special characteristics to look for in choosing polyurethane foam are given below.
Foam reaction time – Slowly reacting foam is good for void filling but not rising concrete.
Foam density – Customized 2 lb. foam box is less expensive than 4 lb. foam. There is less foam and more air in 2 lb. box.
Foam pliability – Good concrete lifting foam needs to set in 15 seconds and remain pliable for about 15 minutes.
Foam aggressiveness – More aggressively foam expands better it is to lift the concrete. Efficient expansion rate is 20 to 25 time’s original volume.
Remember that using incorrect foam can be a waste of money. Therefore choose right foam for efficiency in concrete lifting and levelling.