What Causes Cracks in Walls?

Cracks in walls are common. Some are harmless, some are warning signs. Here's how to tell the difference.

Normal Settling

All houses settle over time. This causes small, hairline cracks, usually:

• Above doors and windows (corners are stress points)
• Along seams where drywall sheets meet
• Where walls meet ceilings

These are cosmetic issues. Fix them, paint them, move on.

Temperature and Humidity Changes

Your house expands and shrinks with the seasons. This movement causes cracks that often:

• Appear in winter and close up in summer
• Show up in the same spots year after year
• Are more common in older homes

Again, mostly cosmetic. Better climate control helps.

Poor Original Work

Sometimes cracks happen because the drywall wasn't installed right:

• Not enough screws
• Tape not properly embedded
• Wrong type of joint compound

These cracks can be fixed properly and won't come back.

The Worrying Ones

Be concerned about cracks that are:

Diagonal cracks from window/door corners - Could indicate foundation movement.

Stair-step cracks in brick or block - Usually foundation settling.

Wide cracks (more than 1/4 inch) - Something is really moving.

Cracks with one side higher than the other - Structural movement.

Cracks that keep growing - The problem isn't done yet.

What to Do

For normal cracks:

• Clean out loose material
• Apply joint compound
• Sand smooth and paint

For worrying cracks:

• Monitor them (mark the ends with tape and date)
• If they grow, call a structural expert
• Don't just cover them up

Most cracks are nothing to lose sleep over. But the ones that signal bigger problems shouldn't be ignored. Also read: why walls crack in winter.