What Makes Poured Concrete Different
Before I bought this house, I looked at one with a block foundation. My buddy Rick said, "Poured is better. One solid piece." Turns out that's mostly true, but poured has its own quirks.
It's Monolithic But Not Perfect
A poured wall is essentially one continuous piece of concrete. No mortar joints like block walls. That makes it stronger against lateral pressure. But the pour has to go right during construction.
Walk around my basement and you can see the horizontal lines where different sections were poured. The crew poured it in layers as they worked their way up. Those lines are called cold joints. If the first layer started setting before the next one went on, the bond isn't perfect there.
Those Little Round Holes
There's a grid of small holes all over my walls, about 2 feet apart in each direction. Took me forever to figure out what they were.
Form ties. When they pour concrete walls, they use forms to hold the wet concrete in place. Metal ties hold the forms the right distance apart. After the forms come off, they snap off the ties and patch the holes. Or they're supposed to. Mine have some sketchy patches.
The Cracks I've Found
I've mapped every crack in my basement. I know, I know. But here's what five years of monitoring has taught me about each type.
The Vertical Shrinkage Cracks
I have three of these. All running roughly vertical, all starting near corners or window openings. All hairline thin. All completely unchanged in five years.
The engineer said these formed when the concrete cured, probably within the first few years after the house was built. Concrete shrinks as it dries. It has to crack somewhere. These are where mine chose to crack. They're done moving. They're just... there.
The Diagonal One Near the Window
This one worried me most. Runs at about a 45-degree angle from the corner of a basement window. Classic settlement crack pattern.
But here's the thing. It's been painted over at least twice. Meaning it was there when the previous owner painted, and the owner before that too. The engineer measured it. Same width top to bottom. Both sides perfectly level. It formed decades ago when the house settled a little, and it's been stable ever since.
I marked it anyway. Four years later, no change. Five years, same thing. My panic was unfounded.
The Form Tie That Leaks
One of those round form tie holes started leaking during heavy rain. Small drip, but annoying. Turns out the patch had cracked or was never great to begin with.
I paid a waterproofing guy $150 to inject it with polyurethane. Took 20 minutes. Problem solved. This wasn't a crack issue, just a bad patch. Common in older poured foundations.
What Would Actually Concern Me
After all this, I know what I'm watching for. Not every crack is equal.
Horizontal Cracks
I don't have any. Thank god. A horizontal crack in a poured wall means the wall is under serious lateral pressure and starting to bow. Poured walls are supposed to be stronger than block against this kind of stress. If a poured wall is cracking horizontally, something significant is pushing on it.
My neighbor's poured wall has a horizontal crack. He's looking at $8,000-10,000 for carbon fiber straps. I check my walls for horizontal cracks every spring.
New Cracks in Old Concrete
My cracks have been there since I bought the house. If I suddenly saw a new one appear after 45 years, that would mean something is causing stress now that wasn't there before. New crack equals new problem.
Cracks That Are Growing
I mark my cracks with pencil. I note the width. I take photos once a year. Paranoid? Sure. But I know nothing is changing. If something started growing, I'd catch it early.
Growing cracks mean ongoing movement. Stable cracks are historical. There's a big difference in how you respond to each.
Displacement
None of my cracks have displacement. Both sides are flush. If one side of a crack shifts forward or back relative to the other, that's real movement. That's the wall actually coming apart, not just separating.
My Annual Basement Ritual
Every spring, I spend about 30 minutes in my basement with a flashlight and my phone.
Check the Marks
I have small pencil marks at the ends of each crack, dated. I check if they've extended. None have.
Take Photos
Same angles, same lighting, same ruler held against the crack for scale. I keep them in a folder. Looking back through five years of identical photos is oddly reassuring.
Level Check
I hold a 4-foot level against each wall in a few spots. Looking for any bow that might be developing. Takes maybe 10 minutes total.
Look for Water Signs
Stains, white crusty efflorescence, any sign that water is getting through somewhere. The form tie leak showed itself this way before I ever saw actual dripping.
This whole ritual costs me nothing and takes half an hour. The peace of mind lasts all year.