5 Effective Ways to Fix Cracks In Ceiling

Cracks in ceilings can indicate underlying issues with your home’s structure, moisture levels, or the materials used. As the owner of Pro Fixing®, I know how worrying it is to see a line appear above your head. You might ask yourself why is the ceiling cracking or whether cracked ceilings are a sign of something serious. In many cases a ceiling crack is caused by normal settling, temperature changes, or minor movement in plasterboard. However, some cracks in the ceiling plasterboard can signal a significant problem.

If you have noticed cracks, don’t panic. In most cases they can be repaired without major upheaval. This guide explains how to fix cracks in ceilings, from small hairline cracks to larger gaps, and when to call a professional. It also outlines ways to prevent ceiling cracks in future. Let’s explore five effective methods to repair cracks so you can restore a smooth, safe finish overhead.

Understand Why the Ceiling Is Cracking

Before you pick up a filler or joint compound, take time to determine why the crack has formed. Some common causes include:

• Natural settling: Homes move slightly over time. This can create small cracks where the plasterboard meets framing.
• Moisture and humidity: Changes in temperature and humidity cause building materials to expand and contract. If ventilation is poor, condensation may lead to plaster cracking on the ceiling.
• Structural movement: Trusses and joists carry the weight of your roof. If they flex due to heavy loads or poor construction, cracks may appear.
• Poor workmanship: If the plaster or tape was not applied correctly, joint compound may crack or tape can pull away.

Identifying the cause helps you choose the best repair method. If cracks are wide, sagging or accompanied by other signs of damage, consult a structural engineer or a professional builder. Hairline cracks often result from minor movement and can be repaired easily.

Fill Small Cracks with Caulk or Filler

For small cracks in ceiling paint or plaster, a good-quality filler or caulk will do the trick. Here’s how to fix small crack in ceiling plaster:

1. Clean the crack: Remove any loose paint or plaster with a scraper. Wipe away dust so the filler adheres properly.
2. Apply filler: Use a flexible gap filler or acrylic caulk. Squeeze it into the crack and smooth it with a putty knife so it blends into the surrounding ceiling.
3. Let it dry: Follow the manufacturer’s instructions on drying time.
4. Sand and paint: Once the filler has dried, lightly sand the area. Then touch up with matching paint to blend the repair.

This method is best for hairline cracks where there is no significant movement. It fills the gap and stops moisture or insects from getting in.

Use Joint Compound for Larger Cracks

If the crack is longer or wider, such as those that run along plasterboard joints, joint compound and tape provide a stronger repair. To fix a larger crack in ceiling drywall:

1. Widen and clean the crack: Use a utility knife to gently widen the crack. This gives the compound something to grip. Remove dust and debris.
2. Apply compound: Spread a thin layer of pre-mixed joint compound over the crack with a drywall knife.
3. Tape the crack: Press self-adhesive drywall tape or paper tape into the compound. This prevents the crack from reopening.
4. Smooth and sand: Apply additional layers of compound, feathering the edges. Allow each coat to dry and sand between applications.
5. Prime and paint: Once smooth, prime the repair and paint to match the surrounding area.

This method works well for cracks caused by slight movement between plasterboard sheets. It reinforces the joint and creates a seamless finish.

Apply Plaster for Very Large Cracks

When cracks are deep or plaster has crumbled away, a more robust solution is needed. In this case, mix plaster or a specialist ceiling repair compound. It is important to use a bonding agent to ensure the new plaster adheres. Here’s how to repair a big crack in the plaster ceiling:

1. Remove loose material: Use a scraper or chisel to clear away any loose or damaged plaster.
2. Apply bonding agent: This helps the new plaster stick to the existing ceiling.
3. Mix and apply plaster: Follow the manufacturer’s instructions to mix the plaster. Apply it in layers, pressing firmly into the crack and smoothing it out.
4. Sand and finish: After each layer dries, sand it lightly. Finish with a skim coat for a smooth surface and then paint.

Working with plaster requires patience and skill. If you are not confident, or if the crack is too significant, call in a professional. Our team’s GIB® stopping specialists ensure a smooth result that matches your existing ceiling texture.

Replace Damaged Sections with New Boards

Some cracks are too severe for fillers or plaster. If the plasterboard has sagged or there is a crack on the ceiling that is wide and deep, replacing the affected section is often the best solution. As a qualified builder, I recommend this method when cracks run across a large area or are associated with water damage.

1. Cut out the damaged area: Use a utility knife and saw to cut around the cracked section. Be careful to avoid electrical cables or pipes.
2. Install a patch: Cut a new piece of plasterboard to fit the hole. Attach it securely to the ceiling joists using screws.
3. Tape and finish: Apply tape over the seams and cover with joint compound. Sand and repeat until smooth.
4. Prime and paint: Match the texture and paint so the repair blends seamlessly.

If multiple areas are cracked or sagging, it may be time to install a new ceiling using plasterboard or a specialist system. Our GIB® fixing experts in Auckland can install new boards quickly and ensure the ceiling is properly supported. They coordinate with our interior plastering and painting contractors teams to finish the job, leaving you with a ceiling that looks as good as new.

Know When to Call a Professional

While many minor cracks can be repaired by a confident DIYer, some situations require professional help. Call a qualified tradesperson if:

• Cracks are wide, long, or accompanied by sagging.
• There is a crack in the ceiling drywall seam that reopens after being filled.
• The ceiling is cracking in multiple places or you see water staining.
• You suspect a structural issue, such as a sagging roof truss or beam.

Our team at Pro Fixing has more than 15 years of experience fixing, stopping and finishing ceilings in Auckland, Wellington and Hamilton. We can assess the cause, recommend the right repair and handle everything from small cracks to full ceiling replacements. You can read more about how different trades work together in our article on why GIB® fixing and stopping go hand‑in‑hand for superior results.

Prevent Future Ceiling Cracks

Once you have repaired your ceiling, follow these tips to minimise the risk of cracks reappearing:

• Maintain a consistent temperature and humidity: Use fans or dehumidifiers to control moisture levels. Sudden swings cause the plasterboard to move.
• Ensure proper ventilation: Good airflow prevents condensation in roof spaces and prevents ceiling paint cracks.
• Check your roof and gutters: Leaks can damage plasterboard. Keep gutters clear and roof joints sealed.
• Avoid heavy loads: Don’t hang overly heavy fittings from the ceiling without proper support.
• Inspect regularly: Keep an eye on any cracks in the ceiling and address them promptly. Early intervention prevents bigger repairs later.

By understanding the causes of ceiling cracks and applying the right repair techniques, you can keep your home safe and looking its best. If you need help, our Pro Fixing team is just a call away.

Pro Fixing®: Best price, high quality, quick and efficient.