When the ground under a structure shifts downward, building settlement occurs. It’s normal for this to happen, especially in the years shortly after a construction project reaches completion. However, excessive structural settling could lead to serious problems.
Small amounts of building settlements might only produce tiny cracks and creaking sounds. If it becomes more severe, it could compromise the structure, harm plumbing systems, or prevent windows from working properly. Large cracks may even appear on the walls.
Potential Causes of Building Settlement
- These problems sometimes develop when construction firms use inadequately compacted soil. Workers might have transported fill to the worksite and neglected to compact it before they fully constructed the foundation. The weight of a building will gradually compress this soil.
- If a new structure sits on clay, this substance could compress as water escapes it. Building settlement slowly takes place as the foundation’s weight creates pressure that causes the water in this soil to flow elsewhere.
- This phenomenon doesn’t only occur as the ground dries. It can also happen if excessive amounts of moisture accumulate in one area. Some types of dirt will soften when they become too wet, allowing foundations to sink.
- If construction personnel neglect to analyze the composition of the soil at a specific location, the builder might design a foundation that produces too much pressure for the underlying ground to support. This error tends to affect homes more often than businesses.
- Building settlements can happen when people bury trees or construction debris in the ground beneath a structure. The objects eventually rot or rust and collapse. This mistake undermines foundations by causing the ground to sink.
- Leaky underground water or sewage pipes have the potential to trigger building settlements because excess moisture softens the ground. Nearby hills and roofs with small or nonexistent eaves can produce similar problems by causing rainwater to flow toward the foundation.
- As trees grow, their roots do as well and can extend underneath structures. They frequently affect the moisture level of the dirt. At the same time, compacted soil may become loose as roots pass through it. Both outcomes can promote building settlement.
Types of Building Settlements
1) Uniform Settlement:
- Description: Uniform settlement occurs when a building settles evenly and uniformly across its entire foundation. In this case, all parts of the structure settle at the same rate and maintain their relative positions.
- Causes: This type of settlement usually occurs when the foundation soil has consistent and uniform characteristics, such as when a building is constructed on a layer of cohesive soil or rock.
- Impact: Uniform settlement is generally less problematic, as it maintains the building’s structural integrity and minimizes damage.
2) Differential Settlement:
- Description: Differential settlement is the uneven settling of different parts of a building or foundation. In this scenario, some areas of the structure settle more than others.
- Causes: Differential settlement often arises due to variations in soil composition, moisture content, or load distribution. It can also result from poor construction practices or inadequate foundation design.
- Impact: This type of settlement can lead to structural damage, cracks in walls and ceilings, and an uneven appearance in the building. It poses a greater challenge for building maintenance and repair.
3) Upward Settlement (Heaving):
- Description: Upward settlement, also known as heaving, occurs when the foundation or soil beneath a building moves upward instead of settling downward. This typically happens in areas with frost or expansive clay soils that expand when freezing or absorbing water.
- Causes: Upward settlement is often caused by soil moisture changes, frost action, or the swelling of expansive soils. It can result in significant structural damage, including warped foundations and cracked walls.
4) Tilting Settlement:
- Description: Tilting settlement is characterized by the tilting or leaning of a building. One side of the structure settles more than the other, causing an angular displacement.
- Causes: This type of settlement can occur when a building’s foundation rests on sloping or uneven terrain or when differential settlement is severe and uneven.
- Impact: Tilting settlement can lead to structural instability, making the building unsafe for occupancy. It may require extensive structural reinforcement or even demolition and reconstruction.
Effective Solutions to Building Settlement
The best way to tackle this problem differs depending on the cause and severity. After thoroughly examining the site, contractors may install new footings, add rain gutters or fix leaky pipes. Compensation grout hardens soil and prevents further settling.
If the issue stems from improper drainage, French drains may be installed around the perimeter of the foundation to divert water away from the building. For sites with expansive clay soils, stabilization procedures can be performed to treat and reinforce the ground prior to construction. In extreme cases where settlement has severely compromised structural integrity, underpinning or lifting may be necessary. This involves either installing new foundation walls underneath the existing structure or using hydraulic jacks to incrementally raise and re-level the building. Regular maintenance and minor foundation repairs can help stop settlement in its early stages before major rehabilitation is required.
The geological and geotechnical professionals at G3SoilWorks can help you analyze and solve the problem of any building settlement. Our team experts know how to identify efficient, safe, and long-term solutions. To get started, please contact the G3SoilWorks office in Costa Mesa via email or phone for an initial consultation.