Different types of drywall are available for various uses in a household. For example, the drywall used in bathrooms and kitchens differs from that used in other rooms. This is due to the need for moisture and mildew protection in areas that may come into contact with water, as discussed in this article on mold-resistant drywall.
Bathrooms need moisture-resistant drywall that will not be damaged when subjected to humid conditions and water splashes. Greenboard and purpleboard drywall are both ideal for the bathroom as they are moisture-resistant.
However, these panels are costlier than standard drywall because of their additional mold and moisture resistance features. Greenboard and purple board drywall have slight differences that make them unique. This article provides you with all the information you need to know about bathroom drywall and which is the best option for your home.
Greenboard drywall
Greenboard is a type of drywall that is moisture resistant. It has a green outer covering that gives it better water resistance properties than regular drywall. This drywall is also more expensive than regular drywall because of its additional water resistance feature.
Greenboard is commonly used in areas where moisture can be an issue, like the basement, laundry room, bathroom, and utility rooms. Some homeowners use it as a tile backer, but this is fast becoming a bad practice because water can pass through the tile grout and cause serious water damage and mold problems.
To maximize the use of green drywall, you can use mold-resistant joint compound or mud. However, you should note that this type of drywall is not ideal for wet zones. Also, the outer green covering resists water, but it is not entirely water-proof. That is why it is not suitable for wet areas. The paper facing this drywall should be treated with mold resisting chemicals to effectively inhibit mold growth.
Several companies manufacture the greenboard drywall. These include the American Gypsum, USG, National Gypsum Company, and Georgia Pacific, among others. This drywall type costs between $14 to $24 per sheet, and it is approximately 20% costlier than regular drywall.
Pros
- It is moisture and mold resistant
- Greenboard is easy to cut and install
- It is easy to repair
- Perfect for lightly damp areas
- Suitable for wall installations
Cons
- This drywall is not entirely water-proof, and it is not suitable for wet areas
- Mold/mildew prevention is not guaranteed
- It is more expensive than regular drywall
- It is not fire-resistant, so it should not be used in places where fire emergencies are high, like the kitchen.
Purple board drywall
Purple board drywall is another excellent option for bathrooms and other areas prone to wetness. It provides similar advantages to regular drywall and greenboard, but it is superior to greenboard because it is resistant to mold, mildew, and moisture. This drywall is specially treated for mold and mildew resistance, and its gypsum core is fire-resistant.
Purple board is perfect for wet areas, and it can get into contact with water without developing any issues. It is, therefore, an excellent choice for areas in need of enhanced mold and moisture resistance.
This drywall features purple paper on its face side and a heavy, mold/mildew/moisture resistant grey paper that has been 100% recycled on its backside. This makes it an excellent choice for your projects.
Like the greenboard, the purple board is also costlier than regular drywall. It costs between $15 and $90 per panel, making it even more expensive than the greenboard. This drywall is only made and patented by US National Gypsum.
Pros
- Ideal for walls and ceilings
- Used as a tile backer board in dry areas
- It inhibits mold/mildew growth
- It is easy and fast to install
- Provides fire resistance
- This drywall effectively resists the moisture barrier
- It comes with square-cut ends and a smooth finish
Cons
- It is heavy, making it difficult to DIY
- This drywall is a lot more expensive than regular drywall
What’s the difference between green and purple drywall?
Purple and green drywall are both excellent options for the bathroom. However, the purple board has superior properties because it is moisture, mold, and mildew resistant. More so, it has a fire-resistant core that makes it a perfect choice for the kitchen or other fire-prone areas.
Greenboard is only water-resistant, and its mold resistance is not guaranteed. The following table highlights the major differences between green and purple drywall.
| Description | Green Drywall | Purple Drywall |
|---|---|---|
| Cost per sq. ft. | $14 - $24 | $15 - $90 |
| Application | Walls | Ceiling |
| Thickness | ½’ and 5/8’ | ½’ and 5/8’ |
| Fire-resistant | No | No |
| Mould-resistance | Not guaranteed | Yes |
| Manufacturers | USG, American Gypsum, etc. | National Gypsum Only |
Which drywall is best for bathrooms?
The best drywall for bathrooms is both the green and purple boards because they are both water-resistant. They are both perfect for areas where moisture and mold can be an issue.
Green drywall, however, is not suitable for wet zones because it is not 100% waterproof. It is best suited for light splashes and moisture but not wet areas. To maximize its mold resistance, mold-resistant mud is used.
On the other hand, purple drywall is an excellent choice for bathrooms because it is moisture, mold, and mildew resistant. It has less than a 5% water absorbance rate, which makes it suitable for wet areas. More so, it has a fire-resist core that makes it ideal for the kitchen or other fire-prone areas.
If you are DIYing your project, ensure you determine what drywall will be ideal for your bathroom, depending on your budget. Purple board is costlier than greenboard, and they are both excellent options as long as they are used properly.
Blue board is also an excellent choice for bathrooms and other high-moisture areas because it is mold and water-resistant, and inexpensive. More so, it is easy to install, and it does not require tape, mud, or paint.
Is there water-proof drywall for showers?
Yes, there is waterproof drywall for showers. According to section 7 of the ASTM C 1396, greenboard and other water-resistant materials, including purple and blue boards, can be applied in highly wet places. So, green and purple drywall are excellent options for showers because of their water-resistance properties.
However, greenboard is not ideal for wet zones because it is resistant to water, but it is not 100% water-proof. It is perfect for light splashes and can be used in shower stalls.
When installing water-resistant drywall on ceilings, caution should be taken. This is because ceiling drywall tends to sag when it becomes subject to high humidity. Textures and finishes that contain moisture can also make ceiling drywall sag over time.
What happens if you use regular drywall in the bathroom?
When you use regular drywall in the bathroom, it may get wet and attract mold clusters. This is because regular drywall is not water-resistant, and it can quickly absorb water when exposed for too long.
Although you can use this drywall above the bathroom’s non-shower and non-tub areas, you will still be risking your home to mold growth. For this reason, it is essential to use water-resistant drywall such as green and purple boards for your bathrooms.
Is there a special primer/ paint for bathroom drywall?
Yes, there is a special primer for bathroom drywall, such as the KILZ kitchen and Bathroom Interior Primer. This primer is among the best for bathroom and kitchen drywall, and it is specially formulated for use in the mentioned areas.
Rust-Oleum Mould Killing Primer and Zinsser Water Tite Waterproofing Primer are also great options for bathroom drywall. When looking for bathroom drywall paint/primer, ensure you choose the best one to ensure your walls will be 100% protected from water. You can ask a professional to guide you in case you are DIYing your project.
Can you tile over drywall in bathrooms?
Although this is a common practice, it is not advisable to tile over drywall in the bathroom. This is because water can still pass through the grout and cause water damage in the walls, studs and cause mold/mildew growth. Wet walls can also attract water-loving bugs that may damage the walls.
Another issue caused by this practice is an endless black discoloration of the tiled shower wall’s bottom part. Water seeps through the grout joints and makes the drywall stay damp endlessly.
Drywall is an inexpensive and highly durable material for walls and ceilings. This makes it very popular among homeowners and investors. Bathrooms need water-resistant drywall that protects the walls from being wet. Before you choose particular drywall, make sure you understand its benefits first and compare it to other similar options first.
