How To Repair Water Damaged Wall Plaster In 6 Easy Steps

Learning how to repair water damaged wall plaster will allow you to fix the problems without professional help. To fix damaged wall plaster, you should first assess the damages, fix the source of the damage, remove the old plaster and apply a joint compound to repair the cracks.

The process is simple enough that beginners can do it. However, you should first equip yourself with the proper knowledge before you take on this task. Read on to learn how to properly repair water damaged wall plaster!

how to repair water damaged wall plaster


Why Should You Fix Damaged Wall Plaster?

For years, builders and homeowners have chosen plaster walls for its soundproofing and insulation properties as well as the high-end look it provides. Plaster walls can take occasional water splashes but are weak to constant moisture.

Allowing plaster to get wet continuously will allow the water to seep into the insides of the wall, damaging the wood and other structures behind it. Once the interior of the plaster wall gets damaged, you might need more extensive repairs. Even if the moisture fails to reach the insides of the wall, it will still contribute to the growth of mold and other health hazards.


How To Fix Water Damaged Plaster

To fix a plaster wall, you need a joint compound, a joint knife, and a putty knife. You should also wear protective equipment such as gloves, glasses, and masks.


Step #1. Assess the damage

The first step of fixing the water-damaged plaster is determining the extent of the damage. Usually, a visual inspection is enough to see all the signs of damaged plaster.

It would be best if you looked for signs of water damage such as flaking paint, water stains ranging from yellow to brown, sagging and flaking plaster, and, at worst, mold. If the plaster is the only thing affected, you can repair the damage on your own. However, if you believe that the damage includes the metalwork and foundations of your home, it would be best if you contact professionals.


Step #2. Fix the source of the water damage

Before you begin fixing the plaster, you should first determine what caused the water damage in the first place. The damage could stem from leaking or burst pipes or appliances that use water, such as the dishwasher.

Most insurance policies cover the repairs for accidental water damage, so do not hesitate to ask for professional plumbing if you have insurance coverage. However, you may opt to do simple pipe repairs yourself.


Step #3. Removing damaged plaster

Now that you have dealt with the cause of the water damage, you can begin to work on the plaster. Start by removing all the soft and peeling parts of the plaster, including degraded lath, using a putty knife.

Poke and dig into the plaster until you find undamaged areas. Make sure to remove all of the damages before moving to the next step.


Step #4. Clean and seal the damage

Now that all of the damage is gone, you can clean the area using a nylon brush. You can also use a vacuum to get rid of the dust in the area.

Using clean water and a rag, wipe the plaster wall to remove lime deposits that could inhibit the adhesion of new plaster. Afterward, leave the wall to dry for a few hours.

After drying, apply an oil-based or quick-drying primer and sealer to block off all contamination. Using a primer is essential for the new plaster to stick appropriately.


Step #5. Repairing the plaster

Now that the wall is clean, dry, and primed, you can begin repairing it. For shallow areas, you can apply several thin coats of joint compound using a joint knife.

Remove any excess using parallel strokes. You should apply it as evenly as possible to avoid unnecessary sanding once it dries.

For big areas, you can use a thin piece of board to apply the joint compound. Place the joint compound on the spot and drag it across to smoothen it. Let the compound set and dry.

Once the joint compound sets, you can sand the area using medium-grit sandpaper. Brush and wipe the sanding dust using a damp piece of cloth.

Once the area is clean and dry, apply a lighter, thinner coat of joint compound. Again, skim the excess, but this time, the direction should be perpendicular to the previous coating. Apply as many coats as needed, constantly skimming the excess off in perpendicular directions compared to the last coat.

Once the compound is dry, sand the area using 120-grit sandpaper until it matches the undamaged parts of the wall. Wipe it with a damp cloth to remove all the dust.


Step #6. Final touches

Now that the plaster is fixed and even, all that remains is using a primer. Applying the primer is essential to protect the area from any future water damages. After the primer dries, you can paint the repaired area with the same color as the surrounding walls.



Knowing how to repair water damaged wall plaster will allow you to make home repairs at a lower price. By following simple assessment, removal, and repair, you can quickly fix the damaged wall plaster. However, if the damage is extensive, you should always consult with professionals.

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