An hour to two, depending on the damaged area’s size.
Cost
$25–$50
Oil-based primers for plaster walls cost around $30. You may also need to buy joint compound and new paint.
Need professional help with your project?
Get quotes from top-rated pros.
What you'll need:
TOOLS
Putty knife
Stiff Brush
Paint roller and paintbrush
SUPPLIES
Oil-based primer
Joint compound
Sandpaper
Cleaning supplies
Paint
Large amounts of water can quickly soften and loosen your wall plaster, causing water damage to your walls. If a leak damages your ceiling or wall plaster, you will notice bubbling or bulging behind the top-layer paint or wallpaper. However, worry not. You can easily repair water-damaged wall plaster on your own unless the damaged area is too big to tackle independently.
Preparing to Repair Water-Damaged Wall Plaster
Start by evaluating the situation. The most obvious signs of water damage are bubbled paint and wallpaper. You can gauge how big the affected area is just by looking or feeling with your hand. Next, you need to check for mold growth. Sometimes, leaks happen behind the wall, and more damage has been done before visible damage appears on the surface. If you confirm mold growth, hire a mold removal professional immediately. Don’t attempt mold removal yourself, as it can cause severe damage to your health.
Choosing the Right Primer
Plaster is extremely vulnerable to moisture and water damage. Therefore, we recommend you purchase an oil-based primer, which costs $25 to $35 per gallon. Make sure you go with a trusted brand. You can also use an aerosol primer or a good wet wall primer.
Clean the affected surface using a damp cloth or a sponge with soap. Sugar soap works the best. This is also a good time to peel off surface paint or wallpaper that is already falling apart under the water damage. Before moving to the next step, you should also lay down some towels to protect your floor.
Remove Affected Plaster
You can remove the damaged plaster once the surface is clean and dry. Usually, you can carve away damaged plaster using a putty knife. For larger areas, you may want to use a prybar. This step can be messy and dusty, so wear a mask to prevent breathing in plaster dust. Be sure to remove all damaged plasters. You will notice the difference as dry, undamaged plaster is much harder.
Use a stiff brush to clean dust off the surface you just worked on. You can also use a vacuum to remove any excess. Next, use a wet sponge to wash the surrounding area. Wait until the wall naturally dries before proceeding with the next step.
Prime and Seal
Once the wall is completely dry, apply your primer. Different primers may require different curing times. Most oil-based primers will cure in 30 to 60 minutes but are best left untouched for one to three hours before applying topcoats. You can also apply multiple primer layers for a stronger seal. Just make sure you let each layer cure completely before adding another.
Make the Repair
Photo: Ruslan Sidorov / iStock / Getty Images Plus / Getty Images
Apply a few layers of joint compound once the primer fully dries. You can find a decent-sized patching plaster at any hardware store for less than $10. Spackle and drywall compounds are also acceptable options. Spread the compound evenly into thin layers and scrape off any excess with a putty knife. Once a layer is dried, smooth the surface before applying another layer. Repeat this process until the wall plaster is fully repaired.
The repair is complete at this point if you are okay with leaving the wall plaster bare. If you want to repaint the wall, move to the final step.
Reapply Paint
Photo: Jung Getty / Moment / Getty Images
Once your final layer of compound is dry and sanded smooth, apply a fresh coat of paint to match your existing wall. You can also add a primer layer to seal off the paint for additional protection.
DIY vs. Hiring a Pro
You can usually repair water-damaged wall plaster on your own. However, if a large area is damaged by water and you need a full replacement of the damaged wall plaster, hire a drywall specialist to upgrade the old plaster to modern drywall. New drywalls cost$1.50 to $3per square foot, and $50 to $100per hour of labor.
Similarly, if the plaster damage is on the ceiling or other places that are hard to reach, or too big to work with, hire a water damage restoration professional to do the job right. They will also tell you if mold is present and if you need to find a mold restoration company.
Frequently Asked Questions
Technically speaking, you can use drywall primer over plasters. However, oil-based primers work the most effectively on wall plasters. Meanwhile, water-based primers work just as well with drywalls. Nowadays, there are also universal primers suitable for drywall and plaster. Overall, you will be fine as long as you are using a trustworthy brand.
Depends on the scale of the damage. If you only entice a small amount of water damage in a limited area, it’s easy to repair the damaged wall plaster yourself. However, if you see a large damage or if the leak has been going on for quite a while, you may need to replace a chunk of the wall plaster.
Painting or plastering over water damaged wall plaster is only a temporary fix and doesn’t fix the real problem. If you must, wait until the surface is completely dry before applying a new layer. However, we recommend you remove the damaged plaster and properly perform a repair or hire a professional to do it. Water damage repair is usually covered by your home insurance.
Damp plaster does dry out, although the drying time depends on several factors, including the type of plaster, the surrounding temperature, moisture content, and the extent of the dampness. Sometimes it can take weeks or months for wall plaster to dry naturally.
Xiao is a full-time writer giving advice and tips on improving living spaces so it functions as a peaceful sanctuary and an efficient factory. She is visual artist with substantial woodshop experience and isn’t afraid to pick up a circular saw. She is also a volunteer builder for Kansas City’s Habitat of Humanity.
Xiao is a full-time writer giving advice and tips on improving living spaces so it functions as a peaceful sanctuary and an efficient factory. She is visual artist with substantial woodshop experience and isn’t afraid to pick up a circular saw. She is also a volunteer builder for Kansas City’s Habitat of Humanity.
The homeowners guide to Water and Smoke Damage
From average costs to expert advice, get all the answers you need to get your job done.
