If you have been researching foundation problems and what causes them, you’ve probably come across the term foundation settlement. On the surface, it sounds pretty benign. Settlement isn’t exactly a word that strikes fear the way “foundation failure” might.
But that is the thing about foundation settlement: It is common. It is almost inevitable. However it can also cause serious structural problems for your home. The difference is a matter of type and degree.
What is Foundation Settlement?
Foundation settlement is basically a fancy term for a building sinking slightly into the ground. When the soil beneath a building isn’t strong enough to support the structure, the building will sink, or “settle” as the soil compresses under the building’s weight.
Many homes undergo a very small degree of settlement. The only sign might be a few hairline cracks in the foundation wall. For others, the settlement is greater and so are the problems it causes.
Why Are Some Cases of Foundation Settlement More Harmful Than Others?
To answer this question, we first need to look at two basic types of foundation settlement.
Uniform Settlement
Uniform settlement occurs when the entire building settles an equal amount. By sinking uniformly across the entire foundation, everything with the building’s structure generally stays in alignment. Uniform settlement can still cause issues, especially if it happens to a significant degree. If your foundation is going to settle, however, you want uniform settlement.
Differential Settlement
Differential settlement occurs when different portions of a building’s foundation settle at a different rate. When this occurs, it places significant stress on the building’s structure, which can lead to cracking. It also throws the house slightly out of alignment. Have you ever wondered why sticking doors and windows can be a sign of foundation problems? It is because of this alignment issue, which can slightly alter the shape of the openings for the door or window.
With differential settlement, the damage itself can sometimes give you a clue as to the settlement. A vertical crack in an exterior brick wall is a common sign of differential settlement. If you look closer at the top and the bottom of the crack, it can help tell you where the greatest settlement is occurring.
If the crack is wider at the top of the wall, it means the settlement is greater along one or both ends of the building. As the stress causes the wall to crack, the downward force on the edge of the wall is going to pull it apart farther at the top.
If the middle section of the house, relative to the wall, is settling faster, the opposite will hold true. The crack will be smaller at the top and wider at the base of the wall.
Why Does Foundation Settlement Occur?
To the degree that many buildings settle slightly it is because, to put it bluntly, buildings are heavy. There are certain issues, however, that can lead to the more dangerous levels of settlement.
- Poorly Compacted Soil: If the soil wasn’t properly compacted before construction, it is unlikely to be strong enough to support the weight of the home
- Erosion: If erosion weakens the soil or causes voids near the building, it can lead to differential settlement.
- Soil Types: Clay soils tend to compress more under load, leading to settlement, while sandy or rocky soils are usually more stable. Clay soils also have greater shrink-swell cycles, which can cause settlement issues during the shrink portion.
What Are Signs My Foundation is Settling?
Basically, take a look at anything that would be affected if the building’s structure shifts out of alignment.
- Wall, Floor or Ceiling Cracks: Not all cracks are indicators of foundation settlement, but cracks are one of the most common signs. Differential settlement places the structural components such as walls or a slab floor under stress, and that stress can eventually lead to cracking. Among the most common places for cracks are emanating from window or door frames because the openings serve as a weak point.
- Windows and Doors Sticking: As noted earlier, the house shifting out of alignment can slightly change the shape of the openings for windows or doors, sticking in some places but leaving gaps in others.
- Tilting Chimney: Chimneys are a long way from the foundation, but they are visible, and if the house shifts slightly out of alignment, the chimney will often begin to tilt.
Do You Suspect Your Oklahoma Home’s Foundation is Settling?
If you believe your home’s foundation is settling and you live within Pierman’s service area, contact us today. We can evaluate your home and, if it is suffering settlement-related damage, lay out your repair options.
