Water Intrusion

What it is

Water intrusion is water getting into places it’s not supposed to be. Through the roof, the walls, the foundation, or up through the slab. It’s the source of roughly 99% of the structural damage you’ll find in houses — the mechanism behind almost every nasty renovation surprise: mold, rot, foundation movement, sloping floors.

Every diagnostic I run on a property starts with three water questions. Is there ongoing bleeding? Can I see it? Can I stop it cheaply? Bleeding is active, ongoing water damage getting worse by the day. If a house is bleeding, nothing else matters until you stop the bleeding. You can’t replace drywall if water is still coming through the wall.

Why it matters

Water always gets in houses. There are a lot of issues that come with outdated or distressed properties, but the one that I am most terrified of is water. You look for any water that could be coming at your house and sitting next to the house — if it sits next to the house, it gets in the house, and it ultimately causes problems.

I’ve learned some expensive lessons on this. I bought a house on a hill and I just couldn’t stop the water from getting into the basement. I did all kinds of things you’d generally do — multiple tiers of retaining walls and French drains, curbs around the house to keep the water off, a sealer across the foundation. I never even thought about the possibility that I wouldn’t actually be able to stop it. Then while digging out a sewer line in the backyard, at the bottom of the hole about 3 feet down, I noticed water flowing like a river. That’s when I learned: on a hill, the ground works like a sponge. There’s almost like a stream running through the hill and there is nothing you can do to stop it. All of those things I did were useless, including finishing the whole basement. Thousands in French drains and retaining walls. Eventually we cut a floor drain in the basement so the water that was coming in could at least get out. I now walk from hills on sight.

How it shows up

Three exterior sources cover most of what you’ll find: negative drainage (grade slopes toward the house), pooling (low spots next to the foundation), and saturation (hillside sponge effect, high water table). Two interior sources cover the rest: plumbing leaks and condensation from air sealing failures.

Practical checks before you make an offer: look at the grade slope. Check gutter drainage and downspout extensions — are they directing water away or letting it pool? Check for staining on interior basement or crawl walls. Check for any soft spot in flooring within six feet of an exterior wall. If you smell mildew anywhere in the house, water is sitting somewhere underneath. And use your nose — you know what mildew smells like.

The other failure mode is failed French drains. When you install drainage systems, it’s a great idea. But over time, dirt and leaves get inside those systems and the water can’t escape. Then it saturates the ground and finds its way back toward the house. A French drain that worked for 10 years can quietly fail and you’d never know until you start seeing moisture on the walls.

One last thing: a home inspector is going to find some of this. But the thing that scares me most is what doesn’t come up on a home inspection. The professional DIY — somebody who thought they knew what they were doing, patched something inside a wall, and now you can’t see it. I’ve bought houses where all the inspection tags looked good and the work was completely wrong. Clues are your defense: soft floors, stained drywall, mildew smell, horizontal cracks in the foundation.

Related

bleeding, structural damage, foundation, crawl space, mold, scope of work, due diligence