What is Foundation Settlement? Its Types and Causes - The Constructor (2024)

FAQs

What is a foundation settlement? ›

Foundation settlement is the gradual sinking of a foundation due to factors like soil compaction, moisture changes in the soil, or natural disasters. Standard foundation settling is minimal and a natural response to environmental changes, but significant shifts require professional intervention.

The soils react differently over time but the 3 major causes of settlement are: drying and shrinking of the soils, wetting and softening of soil and poorly compacted fill soil.

When your foundation is settling, it means your home is essentially sinking into the ground. A small amount of settling can be normal, especially in the first year or two after you've built the home, but when that settling becomes significant, it's important to look at it through the lens of a problem.

Foundations on bedrock settle a negligible amount. In contrary, Foundations in other types of soil such as clay may settle much more. An example of this is Mexico City palace of fine arts has settled more than 15 feet (4.5m) into the clay soil on which it is founded since it was constructed in the early 1930s.

A 1/16-inch crack is quite common when a home starts to settle. These hairline cracks should be vertical and should be between 2-6 inches in length. Having horizontal and diagonal cracks of any size will indicate that you have more than just the “normal” settling.

Settlement is the downward movement of the ground (soil) when a load is applied to it. The load increases the vertical effective stress exerted onto the soil. This stress, in turn, increases the vertical strain in the soil. This increase in vertical strain causes the ground to move downward.

The four main types of settlements are urban, rural, compact, and dispersed. Urban settlements are densely populated and are mostly non-agricultural. They are known as cities or metropolises and are the most populated type of settlement. These settlements take up the most land, resources, and services.

Similarly, American Society of Civil Engineers recommends that total settlement should not exceed 50 mm for residential buildings and 75 mm for industrial buildings, while differential settlement should not exceed 19 mm for residential buildings and 25 mm for industrial buildings.

The first step to estimate foundation settlement is to obtain the soil properties at the foundation level. You can use field and laboratory tests, such as standard penetration test (SPT), cone penetration test (CPT), or triaxial test, to determine the soil type, density, moisture content, strength, and compressibility.

How to Fix It: We fix foundation settlement issues by installing steel foundation piers. These piers will extend beneath the foundation, contacting strong supporting soils that will permanently stabilize your structure.

When to worry about settlement cracks? ›

Foundation cracks come in many varieties, but all could be indicators of a problem with your foundation. If you have horizontal or vertical wall cracks, “stair-step” or diagonal cracking, bulging, buckling foundation walls or pushing in at the bottom or top of the wall, you may need foundation repair.

When should I be worried about my foundation settling? You should be worried about your foundation settling if you notice cracks wider than 1/8 inch. More specifically, horizontal, diagonal, or stair-step cracks indicate different types of concerning foundation movement.

How long do Foundations Settle? For the most part a house will finish settling after about two years. Homes can continue to 'settle' after two years but it may be for different reasons than the initial two years. If your home was built atop soil that was not correctly compacted before the foundation was laid.

Even well-constructed foundations can settle or gradually sink into the ground over time. or gradually sink into the ground over time. However, uniform foundation settling is typically harmless, but differential settling can cause serious problems.

It's important to note that foundation problems and settling are related but different. Settling arises when the soil beneath a foundation compresses, causing the foundation to sink. Foundation problems are caused by differential settlement, which occurs when one part of the foundation settles more than another.