Foundation Cracks – How Bad Are They?

For a house to be strong, the foundation has to be in excellent condition. The foundation is the core base of a house. When your house has cracks on the walls, the doors arent closing, or the windows will not open then you need to repair the foundation. The earlier you address a foundation problem the better because they never get better, and they usually get worse will the passage of time.

The different types of cracks you may see are vertical, horizontal, step, diagonal, and any combination in basements. Vertical cracks in foundations indicate uneven vertical movement of the underlying soil. Horizontal cracks suggest a large, linear area of settlement. Step cracks are commonly found in brick walls with both the mortar and the bricks cracking due to soil movement. Diagonal cracks are a concern because there is no easy way to realign the foundation and have cracks reseal during the leveling process.

Foundation cracks are cosmetically ugly on both the inside and outside. Most home owners do not want to see numerous cracks in their homes even if they are not serious enough to cause structural issues. A foundation crack is a more serious problem if any of the following conditions exist.

1 – The crack increases in width and / or length.

2 – If there is evidence of diagonal or lateral movement of sections of the foundation.

3 – The crack allows water seepage into the home.

4 – Cracks can create access to other parts of the home for termites and other pests.

Larger, more serious cracks may need the services and opinion of a structural engineer. Such an engineer should be contacted if the crack wraps around a corner, or a crack runs from the basement floor to the top of the foundation wall, or if a crack runs horizontally and the wall below it leans on the basement. There may be other situations not mentioned in this article so if there is any doubt then it would be wise to contact an expert.



Remember, most foundation problems are caused by the soil that is supporting the foundation. The soil is moving and thereby moving the foundation too. Cracks in basements and basement walls are often filled so as to prevent water seepage. You can fill minor cracks with epoxy. You can use an expensive method that involves pumping materials with hydraulic forces. Another tool or method that can be used is installing drainage pipes, gravel, a sump pit, filter fabric and a pump.

Cracks in slab on-grade foundations can not be filled – their problem is support – too much or too little because of soil movement. If the soil pushes upward then that is “too much” support and is termed upheaval. If there is too little support the weight of the house and the foundation will cause the foundation to crack and settle until it reaches support, which is soil that has shrunk in volume. The best support structures are those that both resist upward soil movement and provide support when clay soils shrink. These support structures are called drilled piers or an enhanced version known as bell bottom piers.

Extensive cracks get wider and longer and may cause part of the concrete slab to heave or worse collapse. The repairer will recommend mud jacking that will help raise concrete slabs. You will drill lower places of the slab and use pressure to pump concrete hence raising the slab to be of the same level as the rest.

Regardless of the type of crack, if they become longer and wider then some action should be taken by the owner of the property. Foundation cracks that become larger over time can compromise the structural integrity of the house or building.