Last winter, Detroit went 19 straight days without the temperature getting above freezing, hit -10°F, and then jumped to 65°F a few weeks later. A foundation sitting in Southeast Michigan clay feels every one of those swings, and the cracks often show up in spring.
What last winter did
- Detroit had 19 straight days with no high above freezing, from January 22 to February 9, 2026 (National Weather Service).
- The season low was -10°F.
- On February 18 it reached 65°F.
Why freeze-thaw cracks Michigan basement walls
Southeast Michigan sits on heavy clay. “Clay holds water, and when that water freezes it expands,” says Imad “Matt” Mansour, owner of Mansour’s Innovations. Frozen soil pushes on the wall. Then a fast thaw sends meltwater sideways into the loose backfill around the house, right up against the foundation, where it looks for any crack, tie rod hole or joint to get in.
Which cracks to watch and which to fix
- Dry, hairline vertical cracks: common and usually not urgent. Mark the ends with a pencil and the date, and check them each season.
- Vertical cracks that leak: these need to be sealed through the full thickness of the wall. Epoxy crack injection fills the crack from the inside of the basement, no digging. Surface paint or patch won’t hold.
- Tie rod holes: the small round spots left from the concrete forms. They often leak and are sealed the same way.
- Horizontal cracks or a wall bowing inward: this is soil pressure, not just a leak. It needs a structural assessment first. See bowing basement walls and horizontal cracks.
- Water at the joint where the wall meets the floor: that’s the cove joint, and it usually needs drainage like interior drain tile, not crack sealing.
“A thin crack that stays dry often just needs watching,” Mansour says. “Once it leaks, it needs to be sealed through the whole wall, not painted over.” More on telling them apart: vertical vs. horizontal basement cracks.
Fall checklist before the ground freezes
- Walk the basement with a flashlight and mark every crack with tape and the date.
- Extend downspouts at least 6 feet from the foundation.
- Make sure the soil slopes away from the house, not toward it.
- Clear leaves out of window wells and yard drains.
- Test the sump pump by pouring water in the pit.
- Make sure the sump discharge line can’t freeze shut.
Already see a leaking crack or new dampness? Call for a free estimate. Our basement cost estimator gives approximate prices first, and multiple cracks are heavily discounted.
Frequently asked questions
Does freezing and thawing cause foundation cracks?
Freeze-thaw cycles put repeated pressure on basement walls, especially in Southeast Michigan clay, which holds water that expands when it freezes. Thaws then push meltwater against the foundation, so existing cracks start to leak.
Are hairline cracks in a basement wall normal?
Dry, hairline vertical cracks are common in poured walls and usually just need watching. Mark them and check them each season. Fix them once they leak or widen.
How are leaking basement wall cracks repaired?
A leaking vertical crack or tie rod hole is sealed through the full thickness of the wall with epoxy crack injection from inside the basement, with no digging.
When is a basement crack serious?
Horizontal cracks, stair-step cracks in block walls or a wall bowing inward point to soil pressure and need a structural assessment.
Sources: National Weather Service Detroit/Pontiac daily climate records, winter 2025-2026. This guide expands on our press release, Last Winter Swung From -10°F to 65°F in Four Weeks. What That Does to a Michigan Basement Wall, distributed by EIN Presswire on November 8, 2026.
Mansour’s Innovations is a family-owned waterproofing, excavation and plumbing contractor in Shelby Township, Michigan, serving Macomb, Oakland and Wayne counties since 2014. Owner Imad “Matt” Mansour has 20+ years in the trade and the crew has completed 1,600+ projects. Our waterproofing work carries a 25-year transferable limited warranty. We’re open 8 AM to 8 PM, 7 days a week. Call or text (586) 345-7292 or book a free estimate online.
