How to repair plaster walls

Clean the area around the crack of all dirt and grease. Scrape or brush off all old paint.

Before drywall was commonly used houses were built with boards called lath boards. Plaster was forced through the gaps and additional layers of plaster were applied and smoothed.

This created a strong, noise-deadening mold-resistant wall, however, eventually, some plaster walls will crack and buckle – damage that can and should be repaired. Here’s how to repair plaster walls:
 
 

How to repair plaster walls that have cracks

Premixed joint compound is a wonderful product for repairing cracks and even for plastering walls that need repair. It’s easy to work with and doesn’t create the dust or toxins that using plaster does. It also doesn’t harden as quickly, giving you more time to complete the repair.

Step 1

If the repair is indoors, cover the floor and surrounding furniture completely. This is a dusty, messy job. Widen the crack using a wire brush or a scraping knife. Make sure the area around the crack is dirt and grease free. Scrape or brush off all old paint.

Using a spatula or a putty knife force the joint compound into the crack until it is a slightly higher than the surrounding area.

Step 2

Using a spatula or a putty knife force the joint compound into the crack until it is a slightly higher than the surrounding area.

Step 3

Clean any excess compound from the spatula using clean water. Then, while the spatula is still wet, smooth the compound and level it to match the surrounding wall. Allow the compound to dry for 24 to 48 hours.

Always wear a mask or respirator when scraping plaster walls or widening cracks. Most of the older paint contains lead, and breathing plaster dust can lead to severe health problems. Protect yourself even if you are making a small patch.

Step 4

When the repair is thoroughly dry, sand the area using a block sander for small areas or a powered sander for large areas. Smooth out any lines or bumps.

Step 5

Prime and paint the new patch, matching it to the color of the surrounding area.

If the wall has many small hairline cracks, plaster the entire wall. The cost won’t be substantially higher and the result will be far better.

How to repair plaster walls

If the wall has many small hairline cracks, plaster the entire wall. The cost won’t be substantially higher and the result will be far better.

To repair an entire wall, be sure the wall is clean and grease-free. Scrape and sand the wall. Use a gouging tool or drill to make gouge lines or holes in the wall that the joint compound can adhere to. The gouges should be 3 to 4 inches apart. Plaster the wall.

Tools and materials you’ll need

• wire brush
• gouging tool
• spatula
• putty knife
• trowel
• block or power sander
• ventilator
• joint compound
• roller or paint brush
• primer
• paint