How to Repair Ceiling Cracks in 7 Easy Steps

Investigate the Cause

Whether patching up a ceiling crack yourself is the right thing to do depends on the cause. Small hairline cracks are often benign, resulting from natural house settlement. 

But if the crack is wet or water-stained, you likely need to deal with a leak before you do any cosmetic repair work. If the fissure is wide, jagged, runs horizontally (parallel to the wall), or is rapidly expanding, this can be a sign the ceiling crack is serious. Pest infestations and foundational issues are potentially dangerous causes of cracks in ceilings that you’ll need immediate professional assistance to diagnose and deal with.

Prep the Area

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Avoid giving yourself extra clean-up work at the end by doing some simple prep work at the start.

• Move clutter and furniture out of the way. You need room to set up a ladder and work safely. 

• Lay down drop cloths or plastic sheeting to catch debris, wet compound drips, and paint.

• Set up a stable A-frame ladder to comfortably reach the ceiling. Practice ladder safety to avoid a DIY disaster before you even get started.

• Don protective goggles and a facemask to guard against falling debris and billowing dust.

Prep the Crack

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Use a utility or drywall knife to scrape away loose, flaking paint, plaster, or drywall compound, working with the crack rather than across it. Cut away any loose, damaged drywall tape, then use a damp cloth to remove any remaining dust and wait for the area to dry.

If the drywall itself is loose or uneven, use drywall screws to secure it at either side of the crack.

Apply Drywall Tape

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Firmly applying a single layer of adhesive drywall mesh tape or paper directly over the crack helps bond the joint compound, prevent sagging, and strengthen the repair job. Use long strips to cover the length of the crack, ensuring it is in the center of the tape.

Patch the Crack With Filler

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There are various types of drywall mud. Use a pre-mixed joint compound or mix a powdered version with water. Always follow the manufacturer's instructions carefully when mixing.

Put the wet joint compound in a mud pan to make it easy to hold, and scoop the mix as you work. Use a putty knife to apply a layer of compound in one direction, remove any excess as you go, and completely cover the drywall tape. Aim for as thin a layer as possible—thick applications can result in cracking and a poor-quality finish. 

Apply at least three layers of compounds to conceal the crack completely. Always clean the putty knife, and allow the previous coat to dry fully before applying the next.

Smooth the Joint Compound

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Wait at least 24 hours to allow the layers of joint compound to fully dry and turn white, then sand to achieve a smooth finish.

Clean and Paint

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In preparation for painting, use a damp cloth to clear dust particles from the surface. It’s best to start with a paint primer to act as a sealant and promote an even finish. If you can find paint that matches the original ceiling color, repaint the section over the crack. Sometimes, painting the whole ceiling provides a more consistent, fresh finish.