A damaged foundation is one of the most costly repairs that a homeowner might ever face, ranging from an average low of $4,000 to $10,000 and beyond, depending on the scope and severity of the damage. Even minor crack repair can cost $500 per patch job.

But there’s a reason for this: A home’s foundation is the basis for its structural integrity; it’s what keeps the house standing for decades.

So, when the very basis of the structure is compromised, it becomes a safety issue as well as a home maintenance concern. Left unaddressed, foundation problems can not only get worse, they can bring the whole house down.

It doesn’t happen often, thanks to strict building codes in this country and modern construction techniques, but residential structures have been known to collapse from time to time. The risks of injury, or even death, in such an incident are very real.

The rule is simple: The longer you wait to fix it, the worse it will get. And the worse it gets, the more it will cost to fix it.

The Foundation: Starting at the Bottom 

Most foundations built today are made with cement and concrete blocks, which are strong and resilient enough materials to hold a house up for generations. Compared to the brick-and-mortar that home foundations were built on top of 100 years ago, which were (and are) prone to leaking and shifting over time, modern foundations are as close to perfect as you’re going to find in residential construction. Generally speaker, they just work.

But a foundation is only as strong as the ground it sits on top of, and foundations that have been built on expansive soil, improperly compacted soil, or in an otherwise unstable area will likely suffer damage over time. For homeowners, this typically shows up as cracks in walls or doors and windows that suddenly won’t close properly.

What to Look For at Home

See any of the following? Call a structural engineer right away for an assessment.

Indoors: Inside the home, look for cracks that show up in walls and floors and grow over time, especially over doorways or where the walls meet the ceiling. Also keep an eye out for doors that begin to jam or fail to latch, as well as windows that start to stick or won’t close completely. What’s happening is the structure of the house around these doors and windows is shifting, altering their alignment within the frame.

Outside: Look for stair-step cracks running through the grout and along the exterior brick, as well as gaps around doors or windows. Sometimes it may even look like the chimney or front stairs appear to be pulling away from the rest of the structure, which actually indicates that the house is pulling away from these other standalone pieces.

Basement: In the basement, foundation damage is obvious and can often be seen directly on the foundation walls themselves, including signs of cracking in the foundation itself or bulging in concrete or masonry walls. Related signs include walls that are out of alignment, floors that are not level, as well as signs of separation between the foundation walls and the structure above. In a finished basement, look for water damage and areas where moisture is finding its way inside and staining drywall and carpets. This can indicate a crack in the foundation behind the finished drywall that might suggest an even larger problem.

And, even when fixed, foundation trouble can cause costly damage above ground as well. Those cracked walls and damaged doors aren’t going to fix themselves after the foundation problem has been addressed, and the longer a homeowner waits to correct the underlying issue the more severe, and expensive, these secondary effects will become.