Metro Detroit’s freeze-thaw swings put basement walls under pressure

A Shelby Township contractor says last winter’s sharp temperature swings across Metro Detroit helped expose how frost, thaw and clay soil can turn small basement cracks into leaks. Homeowners are being urged to inspect foundations before the ground freezes again.

Why it matters: - Metro Detroit’s rapid freeze-thaw cycles can push water and pressure against basement walls, turning small cracks into leaks. - Clay-rich soil in Southeast Michigan drains slowly and changes shape as it freezes, thaws and dries. - Basement problems often show up in spring, after months of hidden damage.

What happened: - Last winter, Metro Detroit endured a 19-day stretch from January 22 to February 9, 2026 without a high above freezing, based on National Weather Service data reported by WDIV Local 4. - Detroit’s winter low reached -10°F on January 24, then climbed to 65°F on February 18, less than four weeks later. - Imad “Matt” Mansour, owner of Mansour’s Innovations in Shelby Township, said that kind of swing drives many basement crack calls.

The details: - Mansour said frozen clay expands and presses on foundation walls through winter, then thawing snowmelt can move sideways into backfill around a house. - Much of Southeast Michigan sits on old lake bottom, with a poorly drained glacial lakeplain and clay underneath, according to Michigan State University’s Natural Features Inventory. - Michigan’s residential code requires footings to go at least 42 inches deep, matching the state’s frost line. - Detroit’s normal snowfall is 45.0 inches a season under the weather service’s 1991-2020 climate normals. - Home inspectors expect some cracking in poured concrete foundations because concrete shrinks as it cures and houses settle. - Mansour said a dry, thin crack can often be watched, but any crack that leaks needs a through-wall repair, not a surface patch. - Mansour’s crews seal basement cracks from inside homes across Macomb, Oakland and Wayne counties. - Hairline vertical cracks that stay dry should be marked at both ends with a pencil and date so homeowners can track movement. - Vertical cracks that leak are commonly sealed from inside by injecting polyurethane or epoxy under pressure until the crack is filled through the full thickness of the wall. - Polyurethane is used when water is actively coming through because it can seal a wet crack. - Tie-rod holes in poured walls can rust and leak, and Mansour said many leaks in 1990s and 2000s poured-wall subdivisions in Shelby Township come from tie-rod holes and hairline cracks. - Horizontal cracks or a wall that bows inward point to structural pressure from soil and need a structural assessment. - Water at the joint where the wall meets the floor usually comes from pressure under the slab and needs drainage fixes, not injection.

Between the lines: - The warning is less about one storm and more about accumulated winter stress on clay soil, foundation walls and drainage systems. - Crack repairs are not all the same. Some are monitoring jobs, while others signal a structural or drainage problem. - The biggest risk is that homeowners ignore a dry crack in winter and only discover active leakage after spring thaw.

What’s next: - Mansour recommends a fall checkup before the ground freezes. - Homeowners should inspect basement corners and storage areas with a flashlight, then mark any cracks to see whether they grow by spring. - Downspouts should extend at least 6 feet from the foundation. - Soil should slope away from the house with about 6 inches of drop over the first 10 feet. - Window wells should be cleared of leaves, and drains at the bottom should be open. - Sump pumps should be tested by pouring a bucket of water into the pit. - Mansour said a crack found dry in the fall gives homeowners time to watch it, while a spring leak usually puts them in line with many other emergency calls. - Mansour’s Innovations has published a homeowner guide to vertical and horizontal basement cracks, plus foundation crack injection service information and county-by-county repair pages for Macomb, Oakland and Wayne counties.

The bottom line: - In Metro Detroit, winter weather does not just freeze the ground. It can reveal weak points in basement walls that stay hidden until the thaw.