Drywall provides a good option for bathrooms but not the type you probably have in the rest of your home.
Your bathroom is the most humid room in the house, so the best drywall for bathrooms is moisture-resistant. These types of drywall are often named for the color of their front surface.
So, we get:
- Green board drywall
- Blue board drywall.
- Purple drywall.
Green Board Drywall
Green board was introduced in the 1960s, with a thicker coating than regular drywall and protected by wax for water resistance.
Green board drywall is also known simply as green drywall or as MMR board, standing for mold, mildew and moisture resistance. The surfaces of green board and the central gypsum composition are specially designed to resist moisture.
Green board is made from recycled materials, which makes it a popular eco-friendly choice, and it provides a more affordable surface than cement board for areas of a bathroom that are subject to damp but don’t get saturated.
Blue board drywall is treated to achieve strong adhesion to the special plaster that’s formulated for it, and is highly resistant to mold and water. This is why you’ll find it in many bathrooms and other areas with a lot of moisture
Blue board doesn’t require several coats of joint compound to achieve a smooth surface – just tape and plaster on the seams followed by a further thin layer of plaster.
Blue board – aka plaster baseboard – is also more durable than regular drywall in withstanding accidental knocks and for noise reduction.
Purple drywall is used in bathrooms and other areas prone to mildew, moisture and mold. The moisture-resistant core of purple drywall is sandwiched between recycled material that’s mold- resistant.
This type of drywall gets its name from the PURPLE brand family of drywall and cement board products made by National Gypsum. It’s often used in bathrooms around basins, toilets and vanities and as a tile backer for splashbacks and shower ceilings.
Cement Board for Bathrooms
For areas subjected to constant exposure to water – such as tub and shower splashback areas – a waterproof substrate is recommended to ensure tiling stays intact. Cement tile backing board – also known as a cementitious backer unit (CBU) – comprises aggregated cement formed into sheets of varying thickness with fiberglass mesh surfaces.
Unlike plywood and drywall, cement board contains no organic matter, which makes it highly resistant to rot, mold, shrinkage and decomposition. Cement board brands like PermaBase are more expensive than products like green board and need a moisture barrier behind them to make them truly waterproof, which takes more time to install.
Other major brands of cement board include:
- WonderBoard – made by Custom Building Products with a high level of flexibility ideal for curved surfaces.
- Durock – made by USG.
- HardieBacker – made by James Hardie Industries.
What is Mold-Resistant Drywall?
Mold spores need a food source as well as moisture and oxygen. While the central gypsum composition of all drywall is non-organic and naturally mold-resistant, the paper surfaces of standard drywall can provide nourishment for mold.
Preventing mold growth on drywall can be achieved by two techniques:
- Using a non-organic material like fiberglass mesh instead of paper – so mold has no food source.
- Denying mold spores moisture and air – with thicker paper treated with a waxy substance.
Mold-Resistant Drywall Installation
Installing mold-resistant drywall for bathrooms follows the same process as regular drywall installation.
Panels are screwed or nailed to the framing, and the joints covered with drywall tape and drywall mud, which is lightly sanded between coats. The finished surface can be tiled or primed and painted with products designed for mildew and mold resistance.
The best drywall for bathrooms combines mold resistance with moisture resistance, and top brands include:
- Mold Tough – from USG.
- Gold Bond XP – made by National Gypsum Company.
- M-Bloc – from American Gypsum.
- ToughRock – made by Georgia Pacific.
While the latest mold-resistant drywall is also moisture-resistant, it’s not waterproof and won’t prevent mold in the event of flooding – and the manufacturers don’t claim otherwise. In basically dry areas, the extra cost of mold-resistant drywall may not be worth the extra cost but in bathrooms it’s crucial.
Why you need Mold-Resistant Drywal for your Bathroom?
Using the best drywall for bathrooms significantly reduces the health hazard posed by the formation of toxic mold. Bathrooms are particularly susceptible to mold caused by excess moisture and condensation build-up. Mold can produce allergens and toxic substances that affect your body’s immune system or result in respiratory problems such as asthma, and it can be especially dangerous for young children and older people. Moisture-resistant bathroom drywall will help to avoid growth of mold and other harmful bacteria.
Mold-Resistant Drywall Costs
Mold-resistant drywall that also includes moisture-resistance is about 50 per cent more expensive than regular drywall. However, it can potentially add value to your home – mold-resistant drywall is regarded by real estate professionals as a selling feature. As with other kinds of drywall, mold-resistant drywall provides a durable surface that’s easy to maintain.