Foundation

What it is

The foundation is what the house sits on. Three common types: slab-on-grade (a poured concrete pad), crawl space (short perimeter walls with a shallow floor underneath), and full basement (tall perimeter walls enclosing a below-grade room). Each has different failure modes.

Slab problems: cracks wider than a pencil, uneven floors, separation between the slab and the walls. Crawl space problems: moisture, rot on sill plates and floor joists, failing piers, standing water. Basement problems: wall cracks (horizontal cracks are worse than vertical), bowing, water staining, white mineral residue, rust on steel beams.

When you walk a property, I look for the five structural signals: cracked foundations, sloping floors, squishy floors (spongy when you walk), rotted walls, and compromised roofs. The house works like a Jenga tower. Any one of these signals potential failure in the whole stack. Two or more and the deal is likely dead unless you’re priced for a gut.

Why it matters

Foundation issues are the single most common reason a cosmetic flip turns into a gut. I teach a structural damage screen on every walkthrough because foundation problems cascade upward. A shifted foundation cracks drywall, misaligns doors, buckles flooring, and splits trim. Fix the cosmetics without fixing the foundation and the cosmetics break again within a year. Buyers and their inspectors catch this immediately.

The worst foundation situations are on hill lots with water running toward the house. And man, I learned that the hard way.

I bought a house 2/3 of the way up a big hill. It had a basement, unfinished. I figured I could add square footage by finishing it out. I did all kinds of things you’d normally do when there’s water getting into a house — multiple tiers of retaining walls, French drains, curbs around the house, a sealer across the foundation. I never even thought about the possibility that we wouldn’t actually be able to stop the water. So we went ahead and finished the basement.

Right about the same time I noticed moisture all across that front wall and maybe even some mold growing, we were digging out a sewer line in the backyard. At the bottom of that hole, about 3 feet deep, there was water flowing just like a river. That’s when I learned: on a hill like that, it works like a sponge. It’s soaking water inside it and there’s almost like a stream running through the hill. There’s nothing you can do to stop that water.

All of those things I did were useless. Extra cost: massive. The fix ended up being letting water in and pumping it out. Don’t buy a house on a hill.

How it shows up

Practical walk: at every showing, stand at each corner of the house and sight down the wall. Bows, settlement, or waves get flagged. Walk the perimeter checking for negative drainage — ground sloping toward the house — within six feet of the walls. Walk inside: drop a marble in the middle of each room and see which way it rolls. Crack patterns follow stress patterns, so widening cracks near doorframes tell you where the frame is moving.

You should also look for any sort of yard buildup that leads to negative drainage, houses built on unstable or loose soil, and general erosion control. Use your nose. You know what mildew smells like. If there’s mildew in the house, it’s likely because water is sitting somewhere underneath.

If the foundation fails the walk, price the fix before you price the cosmetics — not after.

Related

structural damage, bleeding, crawl space, inspections, the mirage, pro diy