How to Fix Hairline Cracks in Painted Walls [Simple Guide]

Randy Charles
Professional Painter

Randy Charles is the owner of, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years...Read more

Hairline cracks in walls are small, thin lines that you sometimes see on the surfaces of your walls. They are not big, but they can make your walls look not so good. These cracks often happen in painted walls. Painted walls are just your regular walls but with paint on them. The paint makes them look nice and can also protect the wall. But sometimes, the paint cracks.

Why do these hairline cracks show up? Well, your house changes a bit with time. It can move a little when the weather changes. Like, when it gets very hot or very cold. Also, the paint on your walls gets old, and that can make cracks.

You can fix these cracks. It’s not hard. You need some things like spackling paste, a small knife for putty, sandpaper, and paint that looks like your wall color. Spackling paste is a kind of soft material that fills the cracks.

what are Hairline Cracks?

Hairline cracks are very small, thin lines that you can see on walls. These cracks are not wide or deep. They look like fine lines or spiderwebs. You usually find them in the paint or plaster on your walls. Even though they are small, they can make your wall look not so nice. These cracks are common in homes and buildings. They happen for many reasons.

One main reason for hairline cracks is changes in your house. When it gets very hot or cold, your house materials expand or shrink. This can cause cracks. Also, over time, your house settles a bit. This means it moves very slightly on its foundation. This movement can also make hairline cracks. Another reason is old paint. As paint gets older, it can crack and create these fine lines. These cracks are not usually a sign of big problems. But, it’s good to fix them so your walls look nice again.

what causes hairline cracks in painted walls

Hairline cracks in painted walls are common. They are small, thin lines that appear on your wall. These cracks can be caused by several things. Most of the time, they are not a big worry. But, it’s good to know why they happen. This helps you stop more cracks from showing up.

Temperature Changes

Your house reacts to temperature changes. In hot weather, things in your house can expand. In cold weather, they shrink. This movement can cause hairline cracks in your walls. Think about it like a wooden door. Sometimes it sticks in summer but is fine in winter. It’s the same with your walls. When the temperature changes a lot, your walls move a bit. This movement can make small cracks in the paint.

Walls facing the outside feel these temperature changes more. So, you might see more cracks there. To help this, you can use paint that handles temperature changes better.

Humidity and Moisture

Humidity is the amount of water in the air. High humidity can make walls slightly damp. This dampness can cause the paint to crack. Bathrooms and kitchens often have high humidity because of steam. Cracks can show up in these rooms more.

Also, if water leaks into your walls, it can cause cracks. This might happen if there’s a problem with your roof or pipes. Keeping your house dry helps prevent cracks. Use fans in damp rooms. Fix leaks as soon as you find them.

Poor Quality Paint or Painting

The paint itself is the problem. Cheap paint might not stick well to your wall. It can crack easily. Also, if the wall was not prepared right before painting, cracks can happen. Dirt or dust on the wall before painting can stop the paint from sticking well.

When you paint your walls, use good quality paint. Make sure to clean and prime the walls first. This helps the paint stick better and last longer.

How to Fix Hairline Cracks in Painted Walls – A step by step guide


Before you start fixing the cracks, you need some tools and materials. Get a putty knife, spackling paste, sandpaper, and paint that matches your wall. The putty knife is used to apply the spackling paste into the cracks. Spackling paste is a soft, easy-to-use material that fills the cracks. Sandpaper helps you smooth the area after filling it. And the paint is for covering the repaired area so it matches the rest of your wall.

Make sure you have everything ready before you begin. This will make the job easier. You don’t want to stop in the middle of the work to find something you forgot.

Cleaning the Area

You need to clean the cracked area. Use a clean cloth to wipe away any dust or dirt. This step is important because the spackling paste sticks better to a clean surface. If there’s dust, the paste might not fill the crack well.

After wiping, check the crack closely. If there are loose bits of paint or plaster, gently remove them. You want the area around the crack to be as smooth as possible before you apply the paste. This helps the repair blend in with the rest of the wall.

Applying Spackling Paste

It’s time to use the spackling paste. Open the paste and scoop some onto your putty knife. Hold the knife at an angle and press the paste into the crack. You want to fill the crack completely. Make sure the paste goes into the crack, not just over it.

After filling the crack, use the flat side of the knife to smooth the paste. This makes it level with the wall. It might look a bit messy now, but you’ll fix that in the next step. Let the paste dry. Check the instructions on the paste for how long this takes. It’s usually a few hours.

Sanding the Area

After the paste dries, it’s time to sand. Use your fine-grit sandpaper. Sand the area gently until it’s smooth. Be careful not to press too hard. You don’t want to scratch the wall.

Sanding makes the surface even. This is important for a good finish. If you skip this, the repaired spot might look bumpy. After sanding, clean the area again with your cloth. This removes any dust from the sanding.

Painting Over the Repaired Area

The last step is painting. Use a brush or a small roller. Apply the paint over the repaired area. Try to use the same kind of paint that’s on your wall. This helps the repair blend in.

Paint the area smoothly. You might need to do a couple of coats. Let the first coat dry before applying the next one. When you’re done, the repaired crack should be hard to see. Your wall will look like there was never a crack there.


Fixing these small cracks not only makes your home look better but also helps in maintaining it. Small cracks can become bigger problems if not fixed. Now that you can do it yourself, you can keep your walls in great shape. This skill saves you money and keeps your home looking its best.

So, next time you see a hairline crack, you’ll know just what to do. Your walls are an important part of your home, and now you can keep them looking their best.


Can I fix hairline cracks myself or should I call a professional?

You can fix hairline cracks yourself. It’s a simple task. You need some basic tools like spackling paste, a putty knife, sandpaper, and paint. The steps are easy to follow. But, if the cracks are very big or keep coming back, you might need to call a professional.

How do I know if the paint I choose will match my wall?

To match the paint, take a small chip of your wall’s paint to the store. They can help you find the same color. If you can’t do this, take a picture of your wall in good light. Show this at the store for help in choosing the right paint.

What should I do if the crack reappears after I fix it?

If a crack comes back, it might mean there’s a bigger issue. Check if your house is settling or moving too much. Also, see if there’s a moisture problem. For these issues, you might need to talk to a professional.

How long does it take to fix hairline cracks?

Fixing hairline cracks can take a few hours. This includes the time for the spackling paste to dry and for painting. The actual work might only take about an hour. But, you need to wait for things to dry. Each step needs time.

Randy CharlesProfessional Painter

Randy Charles is the owner of, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years of experience in the painting industry, Randy has become an expert in the field and is passionate about helping others learn more about painting. He has written numerous articles on the subject and is committed to providing accurate and up-to-date information to his readers.

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