Is plaster more mold resistant than drywall?

Author: Prof. Frances Lind  |  Last update: Sunday, October 5, 2025

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

Is plaster better than drywall for mold?

Plaster walls are much more resistant to moisture than drywall. Drywall is painted over, of course. Still, if there was water damage, the back side of the drywall can easily grow mold, and all this mold infested drywall will have to be ripped out, usually. Plaster walls are also a more resistant to fire.

Is plaster mold resistant?

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.

Why use plaster instead of drywall?

For one thing, plaster is by nature a more durable finish than drywall, even high-level drywall finishes. In addition, plaster outperforms drywall in a number of key areas, including insulation, soundproofing, and fireproofing. One additional point in plaster's favor is that by nature, mold can't grow in plaster.

Why is plaster no longer used?

In a word, 'cost'. Though there were advantages to the lath and plaster technique – it more easily allowed for ornamental or decorative shapes, provided sound insulation and helped to slow fire spread – new materials superseded lath and plaster because they were simply faster and less expensive to install.

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When did home builders stop using plaster?

In Canada and the United States, wood lath and plaster remained in use until the process was replaced by transitional methods followed by drywall (the North American term for plasterboard) in the mid-twentieth century.

What are the cons of plaster walls?

As time passes, plaster is continually curing harder and harder making it more fragile than drywall. In areas with high traffic, cracks are common in walls and especially ceilings, which can be shattered by age and gravity.

Why do the British plaster over drywall?

Plastering over drywall is a technique used to achieve a smooth, durable, and aesthetically pleasing wall surface. This method combines the simplicity and ease of drywall with the classic finish of plaster, offering both structural and decorative benefits.

Can you plaster directly over drywall?

Plaster veneer may also be applied to ordinary drywall, or over existing walls, but this requires "gluing" the existing wall surface by painting on a special adhesive compound, and then applying a thin layer of "base coat" plaster.

Why do old houses have plaster walls?

Plaster became popular because it is a durable, fire-resistant finish that muffles sound. Plaster is an important part of your house or building's historic character.

Can mold grow under plaster?

Mould can grow on plaster, although it is not always visible. It thrives in damp or humid conditions and can cause serious damage to the walls, ceilings and any other type of plaster. In order to prevent this, it is important to pay attention to signs that mould is present and take appropriate measures to prevent it.

Does mold release work on plaster?

One problem with various methods of mold release is they can clog the surface of the plaster, making it less porous, so clay sticks to it more. So mold release should be cleaned off as much as possible.

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 moisture pass through plaster?

Penetrating damp can spread throughout a structure by moving through porous materials like brick, plaster, wallpaper and wall insulation.

What is the best mold killer for plaster?

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

Is plaster ok in a bathroom?

Yes, you can use plaster in bathrooms, but you must choose the right type of bathroom plaster that is moisture-resistant and suitable for high-humidity environments. Traditional gypsum plaster can be prone to moisture damage, and we do not recommend this product for wet areas like bathrooms.

Why choose plaster over drywall?

When choosing a wall finish for your building, it's important to consider the pros and cons of each option. Plaster offers better quality, fireproofing and soundproofing, while drywall generally costs less and allows for better insulation.

Can you plaster over bad walls?

If the wall has any cracks or damages, they will need to be repaired before plastering. Smaller holes and cracks in a wall can be filled using a sealant such as Caulk. Larger holes and cracks will have to be filled with plaster and mesh, which may be a job for a professional.

Are 1950s homes plaster or drywall?

Homes built before the 1950s likely have some lath and plaster walls unless they were renovated sometime after the 1950s. During the 1950s, pressed gypsum or drywall became the standard for finishing interiors since it was less costly to install.

What do Brits call drywall?

In the UK, it's typically called “plasterboard”, while in the US and some other countries, it's known as “drywall”. Both are made of a gypsum core, sandwiched between paper linings. Regardless of the name, they serve the same purpose: providing a smooth, durable surface that's easy to install and decorate.

How much more expensive is plaster than drywall?

Plaster: Typically more expensive due to the skilled labor and time-intensive application process involved with reports showing that plasterwork can cost between $2 to $10 per square foot.

Why wet the wall before plastering?

Slightly wetting the wall can help the plaster adhere better, but avoid over-saturating it, as this can weaken the plaster's bond. Damp proofing walls before plastering is a vital step in ensuring a durable and moisture-free finish.

What is the lifespan of plaster walls?

Plaster doesn't come with an expiration date. You might hear “15-20 years” thrown around as a lifespan, but that's a very broad estimate. In reality, how long your plaster lasts will depend on a number of factors: The original quality of the plastering job – A poorly done job won't last as long as expert work.

Do all plaster walls have asbestos?

Unfortunately, there wasn't a regulated or realistic way to ensure that all older buildings using plaster walls were asbestos-free. Asbestos was commonly added to plaster until the late 1980s, as it was seen as an inexpensive way to add to the plaster's insulation and fire-retardant properties.

Is it better to hang pictures in plaster or drywall?

Drywall is softer and thinner than plaster walls, and nails can be hammered into drywall without usually causing damage. Plaster is more brittle and can crack or chip, so you will always want to pre-drill a hole in the plaster before adding any hardware, such as a nail, screw, or anchor.

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