Can mold grow behind plaster?

Author: Cesar Ankunding  |  Last update: Thursday, April 9, 2026

Yes, mold can grow on plaster. Just like other types of building materials, plaster that has been painted, is dirty, or has been damaged is prime for mold growth. If you find mold growth on your plaster walls, what can you do about it? Read on to learn about mold remediation and prevention for plaster walls.

How do you know if mold is behind plaster walls?

Musty Smell

If you don't see signs of mold, but you can smell it, it may be hidden in your walls. A musty smell indicates that mold is growing in your home. The smell of mold feels earthy, like rotting leaves or decaying wood in a dense, damp forest.

Can mold grow under plaster?

Mold does not grow on plaster because plaster is non-porous and lime-based or clay. Although plaster does not support microbial growth, if porous cellulose-based material such as drywall is used on the backside of the plaster for support, mold can grow on the drywall.

How do you get rid of mold on plaster walls?

As plasterboard is constructed of layers, using bleach or even a mould wash will only remove the surface mould. The main issue is active mould growing throughout the plasterboard. Unfortunately, the only way to get rid of mould for good is to replace the plasterboard.

Is mold behind drywall a problem?

Mold behind drywall can be dangerous to some people with allergies and breathing issues it can be very dangerous. Not all mold is bad but in homes especially if a leak was present or any moisture bad mold can grow. Lowes and home depot sell mold test kits you can probably order them online as well.

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Can mold behind walls make you sick?

It irritates the nose and throat, which can lead to both sneezing and coughing as your body tries to get rid of the irritant. Inhaling mold spores can also trigger coughing in people with allergies or an asthma attack, for those with asthma.

Does homeowners insurance cover mold?

Homeowners insurance doesn't usually cover mold damage or removal unless it's the result of a covered peril. If the mold in your residence was caused by something sudden or accidental, such as a bursting pipe or some other covered incident on your policy, you may be protected.

What is the best mold killer for plaster?

Bleach: Mix one part bleach with three parts water to offer a strong mold-killing solution.

How do you stop mold from coming through plaster?

This involves applying a waterproof, liquid-applied tanking material to the wall surfaces so as to create an impermeable barrier that prevents water and moisture from penetrating. This will help to protect the plaster and walls from further damage due to mould, dampness and rot.

What are the symptoms of mold exposure?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

Is plaster more mold resistant than drywall?

Drywall provides little to no support to the structure. It is less fire-resistant and mold-resistant than plaster.

How long does it take for plaster to mold?

The plaster will take anywhere between 3 hours and 3 days to fully cure, but it's typically dry enough to remove from the mould in 30min-1hr. It's a good idea to let it finish setting outside of the mould to speed up the process.

How to get rid of mold on walls permanently?

The only effective way to permanently get rid of mould problems is by reducing the build-up of moisture in your home. This can only be achieved through better ventilation.

Can mold penetrate plaster walls?

Yes, mold can grow on plaster.

How do you check for mold without opening walls?

Dip a clean cotton swab into a diluted bleach solution and dab it on your wall. If the area brightens after a while, it is mold. Dirt/dust won't react with bleach. It is mold if you smell something earthy, damp, or musty.

Does a dehumidifier help with mold?

Mould will easily grow and spread if the right conditions are present. So, dehumidifiers don't kill mould, but they can help to prevent it from growing inside your home by reducing humidity. However, the best way to deal with it is to get rid of its source.

How to get rid of mold in plaster?

Mix a solution of one part bleach and four parts water. Take a cloth and wipe this solution across the wall, scrubbing gently until all the mould has been removed. You can then wipe the bleach away and dry the area using a separate cloth.

How to stop mold in bedroom in winter?

a dehumidifier, which extracts moisture from the air, can be bought or hired. wipe down surfaces affected by condensation regularly to prevent mould growth. mould can be removed by washing the surface with a disinfectant or a fungicidal wash. This must be used in accordance with the manufacturers' instructions.

What can you use as a mold release for plaster?

Some more unusual methods of mold release are using shaving cream which is said to leave a lovely waxy film when dry. Or using a thin clay slip; the plaster absorbs the water and leaves a film of clay as a barrier. It can also be useful to use mold release on leather hard clay, prior to pouring the plaster.

What kills 100% of mold?

Hydrogen peroxide, commonly used to disinfect wounds, is active against a wide variety of micro-organisms including mold. It acts by releasing oxygen at a rapid rate, which kills mold by oxidizing the surface and breaking down proteins and DNA.

Who pays for mold remediation?

If there is a covered condition that the homeowner's insurance policy covers that causes mold, then the insurance company will cover mold remediation. Excess water from a natural cause like a roof leaking after a rain storm is usually covered by a homeowners insurance policy.

How expensive is mold removal?

Most mold removal professionals charge around $10 to $25 per square foot. So, if you're removing mold from a 100-square-foot area, you can expect to pay around $1,000 to $2,500. But factors like where the growth is and the mold type can affect how much it costs to remove it.

How do I permanently get rid of mold in my house?

Spray the area with a mixture of water and vinegar - half water, half vinegar. Next, scrub to remove all traces of the mold. For removal of black and white mold, spray the area with the half water and half vinegar solution.

Will insurance pay to replace the entire floor?

Dwelling coverage, on your condo or homeowners policy, may pay to repair or replace your floors and carpet if they're damaged by a covered peril. For instance, if your home's floors are damaged in a fire, your home insurance may pay for new flooring, up to your policy's limits and minus your deductible.

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