How To Repair Large Cracks In Concrete Slab

Mix the concrete patching compound following the manufacturer s directions.

How to repair large cracks in concrete slab.

A single thick concrete slab is often used as the foundation for large buildings called slab on grade foundation resting on compacted subsoil and ensuring the building stays level read this post to know how to fix cracks in slab foundation. Fill the crack up to the surrounding concrete surface. Nearly all newer homes will have reinforced slabs however older homes especially those built in the early sixties or before may not have reinforcement or very little. The photograph of cracks above were taken of shrinkage cracks in a concrete slab floor in a home built in 2006.

Concrete suppliers sometimes add water to make the concrete easier to work with but this weakens the concrete. Feather the edges to get the best appearance. Then fill the remainder of the groove and smooth it over. Slowly draw the gun down the crack forcing a bead of concrete repair caulk deep into the crack.

Trowel the compound into the crack. Welded wire mesh can also help reduce shrinkage cracking but only if it is placed in the middle or upper half of the slab but at least 2 inches below the surface. Stab the trowel into the compound to remove air pockets and help work the patching material deep into the crack. Pour concrete resurfacing mixture into the crack and smooth it out with a rubber floor squeegee.

Add water to the resurfacer mix to get the consistency of pancake batter for the concrete crack filler. The cracks in this case ranged in width measured across the crack from hairline less than 1 16 to. Concrete slabs are essential to the structural stability and design of modern buildings. Then i filled the deep cracks with cheap fine grain sand to make sure it was full all.

It will begin to form a skin in about 20 to 40 minutes and will harden completely in 1 to 2 hours. The best solution is to use less water in the concrete mix. Using a hand grinder i leveled the floor on each side of large crack and widened it to the wide of the grinder. A concrete slab without reinforcement usually will have more cracks and the cracks will be wider than cracks in a reinforced slab.

Shrinkage cracks in poured concrete are easily recognizable and can be distinguished from other types of cracks that occur later in the life of a foundation wall or floor slab.