How to Check for Foundation Cracks After Rain?
Last updated October 26, 2026
The short answer
Start with a Visual Walkaround
Begin your check after the rain stops and the ground has drained a bit. Walk the entire perimeter of your home, looking at the foundation walls from top to bottom. Bring a flashlight to see into shadows and low areas where cracks are easy to miss.
Pay special attention to corners, where the foundation meets the ground, and spots where downspouts or gutters empty. These areas take the most water pressure during a storm. In warm, humid regions, heavy rain is common, so a quick check after each storm is a good habit.
- Look for new cracks that appeared after the rain
- Check for widening of existing cracks
- Inspect the mortar or concrete for flaking or crumbling
- Note any discoloration that suggests water seepage
- Feel for dampness along the crack edges
Check the Inside of Your Home
Inside, inspect the walls and floors near the foundation. Look for cracks in drywall, tile, or concrete floors that line up with exterior cracks. Check door and window frames for gaps or difficulty opening, which can signal foundation movement.
Also look at baseboards and trim for warping or water stains. A musty smell in a crawl space or low-lying area can indicate moisture from a crack. If you notice any of these signs, it's worth getting a professional opinion, especially after a hard rain.
- Examine interior walls for hairline cracks
- Test doors and windows for sticking or misalignment
- Look for water stains on floors or walls near the foundation
- Check for a musty odor in low areas
- Feel the floor for unevenness or sagging
Measure the Crack Size
Use a tape measure or a quarter to gauge the width of any crack. Hairline cracks under an eighth of an inch are often just cosmetic and may not need immediate action. Cracks wider than a quarter-inch, or that are growing, can be a structural concern.
Take photos and note the date and location of each crack. This helps you track changes over time. If a crack appears suddenly after rain, that is a sign that water pressure or soil movement is affecting your foundation.
Look for Water Seepage Signs
Water seepage through a foundation crack leaves telltale signs. Look for white or gray mineral deposits, efflorescence, on the concrete surface. Rust stains or dark streaks can also indicate water has been flowing through the crack.
After a rain, touch the crack to see if it feels damp. You might also see small puddles or wet spots on the floor inside. These signs mean water is getting in, which can lead to bigger issues like mold or wood rot if left unchecked.
When to Call the Pros
If you find a crack wider than a quarter-inch, see signs of structural movement, or notice water leaking through the foundation, it's time to call local water damage pros. They can do a thorough water damage inspection to assess the situation and recommend next steps.
Act quickly, especially if you see standing water or feel dampness. Delaying can let moisture seep into walls, flooring, or drywall, leading to more extensive damage. The pros have the tools to measure moisture levels and determine the right course of action.
Talk to someone now
Phones are answered 24/7 for Daytona Beach and nearby communities.
Call Now (386) 272-5697Frequently asked questions
What causes foundation cracks after rain?
Rain can saturate the soil around your foundation, causing it to expand and contract. This pressure can shift the foundation and create cracks. Poor drainage, such as clogged gutters or improper grading, can make the problem worse by directing water toward the foundation.
Are all foundation cracks serious?
No. Hairline cracks under an eighth of an inch are often cosmetic and may not need immediate repair. However, if a crack is wider, growing, or shows signs of water seepage, it could be serious. A professional inspection can help you determine the right action.
Can I seal foundation cracks myself?
You can seal small, non-structural cracks with a masonry caulk or hydraulic cement. But if the crack is large, actively leaking, or you see signs of structural movement, it's wise to call a professional. Improper sealing can trap water and make the problem worse.