Water Damage Plaster Wall. Tips from Professionals

Have you noticed any strange stains, bubbling or flaking on your plaster walls? Following a flood or a busted pipe, water damage is a regular issue that causes the paint on your plaster walls to chip, crack, and discolor. While it may appear to be innocuous at first, it is critical to address the issue before the problem elevates. Ignoring water damage on your plaster wall can result in costly repairs and even structural damage.

Water Damage Plaster Wall

Before repairing the damaged plaster wall, first fix the cause of the leak, clean the affected surface and ensure it is completely dry. If the area is larger, replacing the old damaged plaster with a fresh layer makes sense. Prime and seal the surface to block the bleeding stains. When fully dry, you can paint the plaster.

In this blog post, I will explain how to fix a water-damaged plaster wall or ceiling in more detail. Including how to know if your ceiling has water damage and how to fix a water-damaged cement wall.

Can you repair water damage plaster wall?

A water-damaged plaster wall can be fixed by following a few simple steps. First, ensure that there are no leaks. Attempting to repair the plaster if water is still (now or later) coming through the wall or ceiling will result in failure and more damage. If the damage is small, you can let the plaster wall dry. If needed, you can fix small areas with some fresh plaster and sand them to get a flat end result. If the damage covers a larger area, I recommend removing the plaster and adding a fresh layer.

Make sure that the plaster wall has dried entirely. Painting over a damp plaster wall will leave unsightly streaks when the water evaporates. To speed up the drying process, you can use a fan together with proper ventilation. Using a dehumidifier is also an excellent option, but I recommend using a professional one. You can rent those in many hardware stores.

When the wall is dry, remove any cracked plaster and replace it with a new layer. If the plaster wall still shows water stains, I recommend using a suitable primer. This primer will form a barrier between the plaster, the old paint, and the new paint. It ensures that the water stain does not show on the new paint.

How do you know if your ceiling has water damage?

Damage on your ceiling can be easy to spot in case of apparent signs such as drips of water through cracks in the ceiling. In other cases, a ceiling leak can also show itself in ways that are more difficult to identify, such as musty odor or insect infestations. 

Other common signs of water damage on your ceiling are:

• Discolored spots, which can be copper, yellow, or brown
• A bulging drywall
• Peeling, cracking, or bubbling  on your wall surfaces
• Discolored growths
• Water stains on your  ceiling
• A sagging ceiling
• Mold

Most of these ceiling water damages are chronic rather than one-time or isolated incidents. The leak indeed passes through the ceiling, but it is also possible that it will continue to leak and drop down to the walls. Ensure that you find the reason for the leak and fix it. If a leak stops by itself, it can restart by itself later.

How do you treat water-damaged plaster?

The best way to treat water-damaged plaster is first to clean and dry the wall or ceiling. After drying, coat the area with a quick-dry primer-sealer. This will form a layer that blocks any residual contamination and prevent water stains from bleeding through the new paint.

If you fail to use a primer, the freshly applied paint may peel off quite soon since the area absorbs it pretty fast. Applying a good primer will seal your damaged plaster effectively as you work on it.

How to Repair Water Damaged Plaster?

Water damage to plaster is common, especially in older homes. The material is susceptible to moisture, and any unrepaired leaks can be problematic. If the water damage is local and small in size, you could try to let it dry. Patch places that are damaged. If the area is larger, it will be better to remove it and plaster it again.

If you paint over a water-damaged surface, the stains will resurface once the paint has dried. This is because moisture evaporates considerably slower than oil-based paints, and the droplets are confined inside the paint coat and cannot escape.

Before applying new paint or wallpaper, you must first remove any residual moisture. Otherwise, it will be a temporary remedy until the water leaks and causes similar damage again.

● Fix Leakages before further work

It is imperative to note that if the dampness on your ceiling is left to dry, the stain will resurface after some time. This is why you must first ensure that the water source problem on the ceiling has been appropriately resolved. Otherwise, it will simply be a time-consuming delaying tactic until the water starts leaking again.

● Costs of Replacement

While plaster restoration is useful, it is also time-consuming and costly, and not everyone has the needed skills. Repairing a broken area of plasterboard is a fairly straightforward and inexpensive procedure if you have free access to the ceiling hollow. If you can’t get to the damaged part of the ceiling, the second option is to replace a whole section of drywall.

● Check for Moisture

Plaster walls are quite durable and should last for many years. But if the wall becomes moist, the plaster may begin to disintegrate. It can also lead to mold that is not good for your health. Removing mold can be challenging. If you do not know how to remove it, I always recommend asking a professional for help. Examine your walls and ceilings regularly for moisture to help you discover problems soon enough.

How do you fix a water-damaged ceiling?

To fix a water damaged ceiling, you should follow a few steps:

● Step 1: Remove the stain

Water damage frequently causes indentation areas in plaster or paint. Particular at locations where water has stayed for long periods. These indentations are ugly and must be repaired before painting can begin.

The Best Way to remove stains from Plaster Surfaces

Use the following tips to clean plaster:

• Be careful with water: Do not use a lot of water to clean a plaster surface. Plaster is a porous material, and it can further damage if a lot of water is used.
• Soft, moist cloth: Use a moist, soft cloth. Soak a soft cloth in warm water and thoroughly squeeze.
• Use mild soap: To better remove stains, you can use some mild soap on your cloth.
• Circular motion: Always use work from top to bottom and in a circular motion.
• Bleach solvent for tough stains: You can use a homemade bleach solvent for tough stains. Mix three cups of water with one cup of bleach. This will fade more tough stains. It also has the added benefit of removing lingering mildew.

● Step 2: Apply a patching compound

Use a patching compound to conceal flaws in your ceiling’s corners and seams. Do not attempt to repair your ceiling without first laying a coat of primer. This will close any gaps or fissures that were opened during the repairing procedure. Allow the patching material to dry fully before you continue with the painting.

● Step 3: Paint the ceiling

You can start painting if all the fixes are done, and the ceiling is dry. Ensure that the ceiling is clean and spots with water damage are treated with a suitable primer. The primer will form a layer between the water stain and the new paint. Else the water stain may also be visible on the new paint.

Does water-damaged plaster need replacing?

If the water damage is local, small in size, and quickly found, you first try drying it. If the damage is more severe, you might need to replace it. Always ensure first that the source of the water has been found and fixed.

Always check that there is no mold. Mold can start quickly and can spread. Removing mold before further work is essential. If you do not know how to do this, I recommend asking a professional for help.

Do plaster walls hold moisture?

Plaster walls can hold moisture. Plaster is primarily made of gypsum and water, making it fragile and easy to get damaged. Additionally, mold can develop quickly on plaster walls, especially when the surfaces are moist. Moist and high humidity levels are perfect breeding grounds for mold.

Unfortunately, plaster walls cannot naturally prevent moisture from entering through cracks or holes. As a result, plaster walls are prone to moisture retention.

To manage trapped moisture on your plaster walls, open windows as often as possible to allow the moisture to escape. Besides, you can also use a fan to help remove excess moisture in situations where the moisture levels are too high.

You can use a dehumidifier, but I always recommend renting commercial dehumidifiers. They can remove a lot more water per hour than a residential dehumidifier.

A dehumidifier pulls in the moisture from the air and dries it out to release dry air back into the room. When used with a fan, this can be highly effective at drying out the drywall quickly.

Bubbling plaster walls

If you have a bubbling wall, you must act promptly before the situation worsens. For a concrete floor, you will need to repair the damp-proof course (DPC) around the perimeter of your property as well as the sub-floor ventilation. If this is not handled, it may lead to more serious problems.

To avoid bubbling plaster, install a suitable drainage system that allows all rainfall or snow meltwater to flow away from the home rather than through the walls. You should also check for cracks on the outside of your house that enable rainfall or snow meltwater to enter.

If you see damp spots on your ceilings and walls from your cellar, there is likely an issue with your house drainage system. If you do not have a drainage system, I recommend considering one. If you do have a drainage system, check that it is not clogged.

If you have a drainage system that uses a sump pump, it could malfunction. In those cases, it can be caused by a defective sump pump or a shoddily built DPC. If you think it is the latter, I recommend that you seek help from specialists who understand how to resolve this problem once and for all.

How to repair water damaged cement wall

If you follow the proper steps, fixing a water-damaged cement wall does not have to be complicated. There are several methods how to repair it affordably.

Use the following steps to repair damages to your cement wall:

● Step 1: Identify the source of the water damage and fix it

In most situations, a pipe or gutter has been damaged or removed from its location, allowing water to flow where it should not go. Determine the exact spot where the water is entering, and fix it. Remember that water leaks do not stop by themselves. In some situations, a drain or gutter that is blocked can be the culprit.

● Step 2: Repair leaks and holes on your wall using hydraulic cement

When you are sure the water source is fixed, you can continue repairing leaks and holes in your wall. If your wall has a drywall finish, remove it from the damaged parts. To fix leaks and holes, you need some sand and cement. This will be readily available at your local hardware store.

You can also use a premixed version, often available in smaller quantities. That way, you do not have to mix cement and sand. You can also use quick cement if available. If you purchase the sand and cement separately, mix them at a 1:3 ratio until they blend well.

Add water when you are ready to start the work. I recommend not to make it very fluid, which will make it more challenging to do the repair. If you added too much water, add more of the sand/cement mixture until you reach the required thickness.

● Step 3: Patch up cracks on your cement wall

When the holes are fixed, you can repair the cracks. For this, you can use products like as Quick-Crete. Patches should be as smooth as possible. Remove any excess material.

● Step 4: Apply a finish if needed

If you prefer to cover your cement wall with drywall, ensure the whole wall is dry. You can use a putty knife to apply drywall paste to your mended area and wait for it to cure before softly sanding it down with finer grits until it smoothens. For improved adherence over paint, put two coats of priming coat over your affected area.