Hairline cracks in the drywall joint are a pretty common issue in many homes, and not usually a sign that your home is in danger of collapse. It's more likely that they've occurred due to settling, changes in temperature, or normal wear and tear over time. While we stress again that they're not often caused by structural issues, they can make walls and ceilings look less polished. The good news? Fixing these small cracks in the drywall surface doesn’t require a professional and can be DIY repairs tackled in an afternoon.

What Causes Small, Hairline Cracks in Drywall?

Before jumping into drywall repairs, it’s helpful to understand what might have caused the cracks in the first place. Hairline cracks often happen because of:

• Temperature fluctuations: Expanding and contracting drywall can lead to small vertical cracks over time.
• Foundation Settlement: As homes naturally settle, walls and ceilings can shift slightly, creating minor cracks.
• Drying out of drywall mud: Improperly applied drywall mud or tape may shrink as it dries, leaving small cracks behind.

Once you know the cause, you can focus on crack repair and preventing them from recurring.

Drywall Tools and Materials

Before you start, gather these tools and supplies:

• Drywall spackling compound
• Joint tape (aka drywall tape, paper tape, fiberglass mesh tape) (depending on repair)
• Drywall screws or repair clips (depending on type of repair)
• Drill or screwdriver
• 120-grit sandpaper (or finer) or sanding sponge (fine grit)
• Utility knife
• 6-inch putty knife or 12-inch taping knife (for feathering)
• Wall paint and primer
• Paint Brush

How to Fix Small Drywall Cracks

To fix a hairline crack in drywall, you don’t need a lot of time, effort, or money. Here’s how to do it step by step:

1. Prepare the Surface: Clean the crack by wiping it gently with a damp cloth to remove any dust or debris. If there’s loose paint or drywall material around the crack, carefully scrape it away using a putty knife or cut it away with the utility knife. This helps the patching material stick properly. If there is protruding debris you can turn around the putty knife and use the rounded end of the handle to apply pressure and push the protrusions until they're lower than the drywall surface.
2. Apply Joint Compound or Spackling Paste: Use a small putty knife to fill the crack with joint compound or spackling paste. Spread it evenly over the crack and press it into the gap to ensure it’s completely filled. Smooth out the excess to make the surface as level as possible.
3. Add Drywall Tape (Optional): For minor cracks that might become larger cracks or deep cracks that might reopen, consider applying a strip of self-adhesive mesh tape over the filled crack. Smooth it out with your putty knife to ensure it sticks flat against the wall.
4. Let It Dry: Allow the joint compound or spackling paste to dry completely. Drying times can vary depending on the product, so check the instructions on the packaging.
5. Sand the Area: Once dry, lightly sand the area using fine-grit sandpaper (around 220 grit) until it’s smooth and flush with the surrounding wall. Be careful not to over-sand. Reapply and feather out another layer of drywall mud if necessary. You might need a couple of layers.
6. Prime and Paint: Apply a coat of primer over the repaired area to seal it and prevent the paint from soaking in unevenly. Once the primer is dry, apply a coat of paint on the area to match the rest of the wall or ceiling.

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Tips for Repairing a Small Ceiling Cracks

Repairing a small cracks in ceilings follows the same basic process, but it may take a little extra effort:

• Use a ladder or scaffold to reach the crack safely.
• Work slowly and carefully to avoid dripping compound onto the floor or yourself.
• Choose a paint color or finish that matches the ceiling texture for a seamless repair.

Preventing Future Drywall Cracks

Although it’s not always possible to stop getting cracks in walls, you can take steps to reduce the chances:

• Control the humidity in your home. Use a dehumidifier in damp areas to prevent excessive moisture, which can weaken drywall.
• Keep it a consistent temperature. Sudden temperature fluctuations can lead to drywall expansion and contraction.
• Check your home’s foundation. OK, so I know we stressed that it probably wasn't structural, but if cracks keep appearing, it could indicate a foundation issue. Ask a professional for help, and see if they notice an underlying issue.

FAQ

How do I repair crack issues that keeps coming back?

For recurring cracks, reinforce the repair by using self-adhesive mesh drywall tape over the crack before applying a coat of mud. You can also use an elastomeric patching compound, which is more flexible and better suited for areas prone to movement.

Can I use a bead of caulk to fill small cracks?

Caulk is not the best option for repairing drywall cracks, as excess caulk doesn’t sand well and can leave a visible texture. Instead, stick to joint compound or spackling paste for a smooth, paintable finish.