Why do foundations sink, and how are they repaired?

It sounds alarming, but it is completely normal for a home to move a little as it settles into the ground. The weight of the house compresses the soil beneath it, and weather changes shift that soil too. Most houses settle about an inch during their first 3 to 10 years.

A sinking foundation is a different problem. If a foundation drops more than a few inches it can compromise the structural integrity of the whole house, opening large cracks and, in the worst cases, threatening collapse. The good news is that sinking foundation repair is possible in most cases when the problem is caught early.

What makes a foundation sink?

Soil is almost always the culprit. The ground compresses or shifts under the weight of the house, and it can also expand when it holds a lot of moisture after heavy rain or snowmelt.

The foundation material matters too. Cinder block expands and contracts with temperature, which makes it more prone to sinking. Erosion is a major cause as well: heavy rain, melting snow, and flash floods can sweep soil out from under a foundation, especially for homes at the bottom of a hill or in a valley with poor drainage.

Warning signs of a sinking foundation

Inspect inside and outside your foundation regularly, and especially right after a storm or between seasons, when the ground shifts the most. Watch for:

• Large cracks in the foundation walls, especially ones wider at the top
• Uneven floors, which you can check with a level or a marble that keeps rolling one way
• Doors and windows that suddenly stick as their frames shift
• New cracks in interior walls, especially above doors and windows
• Pipes that crack or burst as the foundation moves against them

How a sinking foundation is repaired

Start with a professional inspection to measure how far the foundation has moved and find the cause. From there, three methods do the work.

Helical piles are metal stakes screwed into the ground through the foundation until they reach a stable surface like bedrock, then secured with brackets and bolts. They stop further slipping and work best for homes with only slight movement.

Push piers are similar but less invasive, using hydraulic pressure instead of large machinery. They are stronger and more durable, so they suit larger, multi-story homes, and they stop a foundation from sinking further when the problem is caught early.

Polyurethane foam, also called Poly-Lift or polyjacking, is used when a foundation has sunk enough that it needs to be releveled first. High-pressure foam is injected through small holes, expands on contact with air, and pushes the foundation back into place. It is synthetic, does not erode, and can be a permanent fix. Poly-Lifting is done in a few hours and dries within a day, and piers can then be added to keep the problem from returning.

Do you need sinking foundation repair?

The sooner you act, the easier and cheaper the repair. Poly-Lift has helped hundreds of homeowners in the Logan, UT area level, lift, and support sinking foundations safely. Contact us to schedule a consultation and a free estimate.