How to Repair Wall Cracks, When to Worry, & When to Get Help

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How to Repair Wall Cracks, When to Worry, & When to Get Help

How to Repair Wall Cracks, When to Worry, & When to Get Help

Are you seeing cracks in your walls and need to know how to repair wall cracks? Do you see wall cracks creeping across the room? Are gaps appearing between the wall and corners? No need to panic! All cracks in the wall are repairable. Some are normal and easy to fix. Others mean there are deeper problems to fix. Use our guide. Learn what is what and how to fix the damage. Use our table on the types of cracks and gaps. Get information about what causes them. Decide what to fix before and after foundation repairs and which products work best to keep your home sturdy and beautiful. Follow our overview and when and where to make those fixes.

Types of Wall Cracks and Gaps & What They Mean

Common Cracks and Gaps

Type of Crack/Gaps	Appearance	Possible Cause	Foundation-Related?
Hairline Cracks	Thin as a thread, often in drywall or plaster	Paint shrinkage, minor settling	Usually not
Vertical Cracks	Runs up and down	Normal settling or slight foundation shifts	Sometimes
Horizontal Cracks	Runs side to side	Excessive foundation movement, possible structural issue	Yes! Get it checked!
Stair-Step Cracks	Follows mortar lines in brick or block walls	Foundation movement or soil issues	Yes! Big warning sign
Wide Gaps at Doors/Windows	Gaps between trim and walls	Foundation shifting, framing movement	Yes, especially if worsening
Baseboard Separation	Gaps forming at floor level	Foundation settling, humidity changes	Sometimes
Drywall Tape Buckling	Tape peeling or bubbling	Moisture issues, minor shifts	Usually not, but keep an eye on it
Bowing Walls	Walls curving inward	High external pressure, foundation failure	Yes, serious issue!
Bulging Cracks	Cracks with bulging or displacement	Structural stress, foundation failure	Yes, immediate attention needed!

When to Worry About Cracks in the Walls

Not all cracks spell disaster, but some require urgent attention. Here’s how to tell when a crack is serious:

Learn How to Repair wall cracks adn know when are they serious

Get started on Our How to for fixing cracks in drywall

Harmless Cracks:

Hairline cracks in drywall or sheetrock
Small cracks due to paint shrinkage
Slight vertical cracks from normal settling

Serious Cracks:

Horizontal cracks in walls
Wide stair-step cracks in brick or block walls
Bulging cracks or bowing walls
Recurring cracks that keep coming back after repairs
Large gaps around windows and doors

Dangerous Cracks:

Cracks wider than 1/8 inch
Cracks that run from floor to ceiling
Structural cracks causing separation in walls
Cracks with water leakage or moisture damage
Cracks accompanied by sloping floors or sticking doors/windows

Step-by-Step DIY Guide to Fixing Cracks in Drywall

Fixing Hairline Cracks in Drywall/Sheetrock

Widen the crack a bit using a putty knife. It makes for adhesion. Apply spackling paste or lightweight joint compound. Again, using a putty knife, smooth the surface. Then let it dry. Sand lightly and repaint.

Drywall Corner Cracks Repair

Remove any loose material from the corner. Apply joint compound and embed mesh tape for reinforcement. Once dry, add another thin layer of mud. Sand smooth and paint.

Fixing Recurring Cracks

Scrape out the old repair material. Use a flexible compound like elastomeric caulk or polyurethane sealant. Apply mesh tape to reinforce the crack. Layer with joint compound and sand when dry. Paint over for a seamless finish.

Repairing Wide Cracks and Gaps

Clean out the crack and remove debris. Use epoxy filler or polyurethane sealant for flexibility. Apply multiple thin layers of compound if necessary. Sand, prime, and paint.

Fixing Bulging Cracks in Walls

Assess if structural reinforcement is needed. Remove loose plaster or drywall. Apply mesh tape and joint compound in layers. If the wall is still bulging, consult a professional.

Repair Bowing Walls

If a wall is bowing, it usually requires foundation stabilization. Consult a foundation specialist immediately to prevent collapse.

Understanding Repair Materials

Flexible Compounds vs. Rigid Compounds

Flexible Compounds (Polyurethane, Silicone, Elastomeric Caulk)

Best for cracks that may continue to shift.
Expands and contracts with wall movement.
It is ideal for foundation cracks, exterior wall gaps, and recurring cracks.

Rigid Compounds (Spackle, Joint Compound, Plaster, Mortar Repair)

Provides a smooth finish but may crack again if the wall shifts.
Best for interior drywall repairs and finishing.

Different Types of Tape for Crack Repairs

Mesh Tape: Strong, flexible, and great for wide or recurring cracks.
Paper Tape: Best for smooth drywall cracks at seams but not flexible for shifting walls.
Fiberglass Tape: Ideal for reinforcing cracks in high-movement areas.

Understanding Mud for Wall Crack Repairs

Lightweight Joint Compound: Dries quickly, best for small cracks.
All-Purpose Mud: Versatile for general wall repairs.
Setting-Type Mud: Fast-drying for deeper cracks, but harder to sand.

Time for Drywall Patch Repair and to Fix Wall Cracks?

✘ Before Foundation Repair? No—wait until the foundation is stable.

✅ After Foundation Repair? Yes—once the structure has settled.

✅ During Dry Seasons? Yes—allows for accurate crack assessment.

✅ After Water Leaks Are Fixed? Yes—prevents moisture damage recurrence.

Preventative Measures for Future Cracks

Maintain Proper Drainage – Direct rainwater away from your home’s foundation. It helps to prevent shifting.
Monitor Humidity Levels – Sudden humidity changes are a problem. The extra moisture causes materials to expand and contract. That leads to the cracks you see. Consider getting a dehumidifier to help moderate in-house moisture levels.
Reinforce – Your foundation is fixed, but cracks recur. No what? Bring in a contractor. See if you need extra support beams or braces that can reduce movement in key areas of your home.
Schedule Regular Inspections – Catch small issues before they turn into major repairs.