Instant Hairline Crack Fixing

Hairline Cracks in Foundations

Whether you recently bought your home or have lived in the same house for decades, the structure might seem as solid as a rock—until you spot a crack in the foundation. It’s easy to worry, but not all cracks spell disaster. In fact, hairline cracks in foundations are quite common, especially in newer homes. But how do you know which cracks are normal and which ones signal bigger problems? Let’s break it down, starting with why foundations crack in the first place.

What Causes Foundation Cracks?

Foundation cracks can develop for several reasons. Here are the most common culprits:

• Curing concrete: When a foundation is first poured, the concrete goes through a curing process. As it dries, it shrinks slightly, which can result in tiny hairline cracks. This is completely normal and usually nothing to worry about.
• Foundation settlement: Over time, your home’s foundation will settle into the ground. While this is a natural occurrence, uneven settlement can cause cracks.
• Shifting soil: The soil beneath your foundation moves in response to changing moisture levels. During dry spells, the soil shrinks and compacts, and after heavy rains, it grows heavy and expands, putting stress on your foundation and leading to cracks.

Types of Foundation Cracks

Not all foundation cracks are the same. The direction and size of a crack tell you a lot about what’s going on under the surface.

• Horizontal cracks run parallel to the ground and are often the result of pressure from the surrounding soil. These are among the most serious foundation cracks and may indicate structural issues.
• Diagonal cracks often occur when one side of the house settles more than the other. These should be monitored closely, especially if they widen over time.
• Stair-step cracks follow the mortar joints in cinder blocks or brick walls, indicating foundation movement. If they grow or show signs of displacement, it’s time to call a professional.
• Vertical cracks are more common and less concerning. They usually form from normal settling and are often nothing to worry about.
• Hairline cracks are thin, barely noticeable fissures that don’t seem to be expanding. They’re often found in newer homes, appearing one year or more after construction is complete as the concrete foundation fully cures.

Are Hairline Cracks in Foundations Normal?

Yes, hairline cracks in foundations are usually harmless and easy to repair. These tiny cracks are less than 1/16-inch wide, do not indicate structural issues, and can be safely left alone if they don’t widen. However, it’s important to know when cracks are a cause for concern. Here’s when you should start to worry:

• Cracks have grown wider than 1/8 inch.
• Cracks are widening or expanding noticeably over time.
• Horizontal or stair-step cracks have appeared.
• Cracks are accompanied by signs of water intrusion.
• A cracked wall appears to bow inward or bulge outward.
• Windows and doors are misaligned and don’t open or close properly.

How to Fix Hairline Cracks in Foundation Walls

If you’ve spotted a hairline crack, follow this quick DIY guide to fix it yourself:

• Clean the crack: Remove dirt, debris, or loose concrete using a wire brush.
• Widen the crack (optional): If the crack is very fine, you may want to use a chisel to widen it slightly. This helps ensure the filler goes deep enough to make a strong repair.
• Inject epoxy or polyurethane: Inject your chosen filler into the crack using a caulk gun or syringe. Epoxy and polyurethane are flexible, so they shouldn’t crack if the foundation continues to shift slightly.
• Smooth the surface: Remove excess material from the patched area using a putty knife.
• Paint: Once the filler is dry, paint it to match the surrounding wall.
• Monitor the crack: Even after a DIY repair, keep an eye on the area to make sure the crack doesn’t reappear or spread. If it does, call a professional for an evaluation.

When You Need a Professional

While repairing a hairline crack in your foundation is an easy DIY job, larger cracks are more than just cosmetic. If you’re unsure about a crack, it’s best to have a professional take a look.

Everdry Waterproofing of Wisconsin has served the Greater Milwaukee area since 1989, with more than 100,000 satisfied customers over the past 35+ years. Whether your home’s foundation is poured concrete, block, brick, or stone, we can repair foundation cracks and implement patented waterproofing methods to ensure your home stays dry and stable. We also offer free inspections, where we explain the condition of your foundation with no obligation to commit. Contact us today for a no-pressure foundation crack repair estimate in Southeast Wisconsin.