Concrete Floor Settlement Cracks

There are three main types of cracks in concrete.

Concrete floor settlement cracks.

Before we describe crack movement and damage patterns and diagnosis in concrete slabs we need to introduce three different types of poured concrete floor slabs. Failure to tie the concrete floor into the foundation wall with steel reinforcement during the initial pour can exacerbate this cracking issue resulting in wide or wider cracks where the. The resulting uneven surface can create a tripping hazard. However if any of the following signs are present then they could indicate a larger issue.

Concrete floors with cracks or larger should be leveled. When a foundation settles the concrete slab can crack and the part of the slab that s less supported sinks into the depression. We use the three carson dunlop associates sketches shown here to comment on the occurrence causes and significance of cracks and movement in poured concrete slab construction. If the crack is larger or growing larger an active crack or one side of the crack is higher than the other then you may need to have the work reviewed by a structural engineer.

In some instances it may be necessary to excavate the area and prepare it for a course of sand to prevent settlement and future cracking. Each has its own cause and strategies to prevent or minimize. American concrete institute touches on the issue of cracking concrete in their american concrete institute manual aci 302. This shrinkage tends to pull or tear the concrete apart.

If you see jagged cracks running at 45 degree angles throughout your home this is a telltale sign that your foundation is shifting. My own home has hairline cracks in the foundation as well as numerous cracks in the basement floor. The settlement crack may also appear as a random crack over areas where the soil of the subgrade was not level or where it settled unevenly after the concrete was poured. Your floor may be cracking or the walls may be separating from the floor below or ceiling above.

Concrete shrinks as it dries and cures. Settlement cracks in a conventional concrete floor slab which has been poured inside a separate foundation wall and often resting at its edges on the building s foundation wall footings are usually not connected to the foundation wall and are not supporting any structure except possibly lally columns discussed below. The cracks are normal concrete shrinkage cracks. Your concrete slab floor is showing signs of sinking sagging or settling.

Crack types solutions. It is not uncommon to see 1 16th inch of shrinkage for every 10 feet of concrete length. Even with the best floor designs and proper construction it is unrealistic to expect crack free and curl free floors.