What Are The Various Types Of Drywall Boards For Wet Areas?

Choosing the right drywall board is crucial when installing tiles in areas exposed to moisture, especially in bathrooms and showers. Moisture poses a significant threat to any wall structure, and without the proper substrate, water can seep through tiles and grout, leading to damage, mould, and eventual structural issues. 

While tiling may seem like the key element of a bathroom renovation, what lies beneath the tile is just as important—if not more so. This blog will explore the different types of drywall boards and determine which is best for wet areas.

Let’s get straight to the point.

When installing tiles in wet areas, choosing the right drywall board is essential to prevent water damage and mould. Regular drywall should never be used in wet areas, while blue and green boards offer better moisture resistance but still require a waterproof membrane. 

A cement backer board is the best choice for high-moisture environments like showers. It is water-resistant and durable. Proper installation, including sealing seams and applying a waterproof membrane, is crucial for long-term protection.

Types Of Drywall Boards And Their Suitability

1. Regular Drywall (Not Recommended)

While regular drywall is common in most parts of the home, it is highly unsuitable for use in wet areas like bathrooms and showers. Regular drywall is made from gypsum, which absorbs water and deteriorates when exposed to moisture. Once water penetrates the tiles and reaches regular drywall, it can cause the board to swell, weaken, and even crumble, compromising the entire wall structure.

Sometimes, homeowners may be tempted to use regular drywall to cut costs. However, this is a risky choice, even with a waterproof membrane behind the drywall. Over time, water will inevitably reach the drywall, causing it to break down and potentially leading to expensive repairs.

Best Use Case: Regular drywall should only be used in dry areas like living rooms, bedrooms, and other non-moisture-exposed home parts.

2. Blueboard (Better Option, But Needs Waterproofing)

Blueboard is a type of plasterboard commonly used in bathrooms. It offers some water resistance, named for its blue paper facing, making it more moisture-resistant than regular drywall. Blueboard is often used as a base for veneer plaster and is a better option than regular drywall for damp areas.

However, despite its better water resistance, the blue board still requires the addition of a waterproof membrane between the board and the tiles. The membrane acts as a barrier to prevent water from penetrating the board, which, over time, can still suffer damage from prolonged exposure to moisture.

The installation process for the blue board is straightforward, similar to regular drywall, making it a common choice for homeowners who want a quick and easy solution. That said, without the proper waterproofing, the blue board alone cannot withstand the continuous moisture in shower areas.

Best Use Case: Suitable for areas with light moisture exposure when paired with a waterproof membrane.

3. Greenboard (Good For Moisture, But Not The Best For Showers)

Greenboard is another moisture-resistant drywall that gets its name from the green paper backing used during production. This green backing is designed to make the drywall more moisture-resistant than regular drywall. Additionally, greenboard is often made from recycled materials, making it an environmentally friendly option for those who want to minimise their environmental impact.

While green board offers better water resistance than regular drywall and blue board, it is still not the best choice for high-moisture areas like showers. Like blue board, green board requires the installation of a waterproof membrane to provide adequate protection against moisture. Without this barrier, water can seep through the tiles and compromise the green board over time.

One of the main benefits of greenboard is its eco-friendly construction, making it a good choice for environmentally conscious homeowners. However, more robust options are available for high-moisture areas, like showers, that provide better long-term protection.

Best Use Case: Suitable for damp environments but not ideal for continuous moisture exposure without additional waterproofing.

4. Cement Backerboard (The Best Option For Showers)

A cement backer board is the best material for tiling wet areas like showers. Made from cement and reinforced with fibreglass, it is incredibly durable and completely water-resistant. Unlike gypsum-based products like regular drywall, blue board, and green board, cement backer board will not absorb water or degrade over time, making it the ideal choice for high-moisture areas.

A cement backer board provides a stable, solid surface for tile installations, ensuring your tiles remain secure and structurally sound even in the wettest conditions. In addition, the cement backer board does not require the installation of a waterproof membrane in most cases. However, adding one can provide more peace of mind in moisture-prone environments.

Installing cement backer boards is more labour-intensive than other drywall options. The board is heavier and requires concrete screws to attach it to the wall studs. Cutting cement backer boards to size also requires special tools like a jigsaw, making it a more challenging material to work with. However, the effort is worth it for long-lasting cement backer board protection.

Best Use Case: Ideal for showers, bathrooms, and other areas exposed to high moisture levels.

Common Issues With Improper Drywall Use

Tile Failure Due To Water Damage

When regular drywall or moisture-resistant boards like blue or green boards are used in shower areas, they are often unable to withstand long-term exposure to water. Over time, moisture penetrates the grout, leading to damage behind the tiles. This can cause tiles to become loose or fall off entirely. Homeowners may notice that the tiles feel soft or “squishy” when touched, signalling that the underlying drywall has been weakened by moisture, leading to potential structural damage.

Mould And Mildew Growth

In bathrooms where moisture seeps through improperly sealed grout into the drywall, mould and mildew can grow unchecked. This presents aesthetic and odour issues and serious health concerns, particularly for respiratory patients. Mould remediation can be expensive, and in severe cases, large sections of drywall and tile may need to be replaced, further increasing costs and inconvenience.

Persistent Grout And Caulking Discolouration

Improper drywall selection, such as regular drywall without adequate waterproofing, can cause grout and caulking to discolour over time, turning black from mould growth. Even with frequent cleaning, the mould reappears due to moisture trapped behind the tiles. This is a common and persistent issue that affects both the appearance of the shower and its hygiene, often requiring extensive repairs to correct the underlying moisture problem.

These issues highlight the importance of proper waterproofing methods and materials in shower installations, such as cement boards or specialised waterproof drywall alternatives designed for wet environments.

The Role Of Waterproof Membranes And Vapour Barriers

Regardless of which type of drywall board you choose, installing a waterproof membrane is critical for preventing water from reaching the substrate. Waterproof membranes are applied on top of the drywall board before the tiles are installed, creating a barrier that protects the board from water seepage.

Vapour barriers are another important layer of protection in addition to waterproof membranes. They prevent moisture from moving through walls, particularly important for exterior walls where condensation can build up inside the wall assembly. Installing a vapour barrier behind the drywall board helps protect the wall’s structural integrity and prevents moisture build-up.

Installation Tips For Drywall 

When installing drywall boards in wet areas, following proper installation procedures is essential to ensure a durable, moisture-resistant finish. Here are the key steps to follow:

1. Remove Old Tiles and Drywall: Remove any existing tiles and drywall. This process can be messy, so wearing protective goggles and keeping the area well-ventilated is important.
2. Prepare the Space: Ensure that the area is dry, and inspect the wall studs for any signs of water damage or mould. Address any issues before proceeding with the installation of new drywall.
3. Install the Drywall Board: Choose the appropriate one based on your needs. For showers, cement backerboard is the best choice. Use concrete screws to secure it to the wall studs.
4. Seal the Seams: Use seam tape to cover the joints between the boards. This prevents moisture from seeping through the seams and weakening the structure.
5. Apply a Waterproof Membrane: Before tiling, apply a waterproof membrane over the entire surface of the drywall board. This additional layer of protection ensures that moisture does not reach the drywall.
6. Tile Installation: You can tile the area once the waterproof membrane is in place. Use high-quality grout and caulk to seal the edges further and prevent water infiltration.

Conclusion

The cement backer board is the winner when choosing the best drywall board for wet areas. Its unmatched durability, water resistance, and strength make it the best choice for ensuring the longevity and stability of your tile installation. While blue and green boards offer some moisture resistance, they are not as reliable for high-moisture areas and should always be paired with a waterproof membrane.

Investing in high-quality materials like cement backerboard and taking the necessary steps to waterproof your bathroom properly will save you from costly repairs. Showers and bathrooms are prone to moisture exposure, and by using the right drywall board, you can protect your walls from water damage and enjoy a beautiful, long-lasting tiled surface for years to come.

FAQs About Drywall Boards For Shower Tile Installation

Can I Use Regular Drywall For Shower Walls?

While regular drywall can technically be used for shower walls, it’s highly discouraged. Regular drywall is not water-resistant and will deteriorate quickly in wet environments, causing tiles to loosen and the wall to fail. If you must use regular drywall, a water barrier must be installed behind it, but it’s best to opt for moisture-resistant options like cement backer board.

What Is The Best Type Of Drywall Board For Shower Tile Installation?

A cement backer board is the best choice for shower tile installations. It offers maximum water resistance and durability and is designed specifically for high-moisture environments. While heavier and slightly more challenging to install, its reliability makes it worthwhile.

Do I Need A Vapour Barrier Behind All Types Of Drywall Boards?

A vapour barrier is essential for all shower drywall boards, including cement backer boards. It prevents water vapour from condensing inside the wall assembly, which could lead to structural damage and mould growth. Plastic sheeting is commonly used for this purpose.

What’s The Difference Between Blueboard And Greenboard?

Blueboard and greenboard are similar in function but differ in composition. Greenboard is made from recycled materials, making it a more eco-friendly option. Both types require a waterproof membrane to prevent moisture from penetrating the board.

How Can I Maintain My Tiled Shower Walls To Prevent Water Damage?

To maintain tiled shower walls:

• Regularly inspect grout and tiles for cracks or gaps and repair them promptly.
• Reapply caulking where the shower base meets the wall every few months.
• Use a high-quality bathroom exhaust fan to reduce humidity and prevent mould growth.

Proper maintenance will extend the life of your shower and keep it free from water damage.