Worried about what drywall to use in bathroom? Just like specific paints and tiles are best for different parts of your home, different types of drywall are also suited for certain areas.
Standard drywall, which has a gypsum-based core, is great for spaces like the living room, dining room, and bedrooms. But what about areas where the drywall might get wet? For these places, there’s a special type of drywall known as “green board,” which is commonly used by drywall contractors.
What is Green Board?
Greenboard drywall is a type of drywall with a special paper cover that has been coated with wax and chemicals to keep out moisture and prevent mold.
Green board is easier to install and costs less than cement board. The name comes from the green color on one side, which helps installers know where to apply more joint compound.
Is Green Board Waterproof?
Green board is water-resistant, not waterproof. It works well in areas like bathrooms and kitchens where there is a lot of moisture in the air. However, it’s not suitable for places like showers where it will have direct contact with water.
In places where drywall might get wet, it’s a good idea to consider using cement board instead.
Dimensions of Green Board
Greenboard drywall, which is water-resistant, typically comes in two main thicknesses: 1/2-inch and 5/8-inch. The most common size for green board sheets is 4 feet by 8 feet. Additionally, it is available in larger sizes such as 4 feet by 10 feet and 5 feet by 10 feet, which are often preferred by professionals.
It’s important to note that while greenboard drywall shares the same 5/8-inch thickness as Type X drywall, it is not the same as Type X, which is fire-resistant drywall. Type X drywall is specifically designed for use in areas like kitchens where fire hazards are a concern, and it is required by building codes for garage walls.
Greenboard vs. Conventional Drywall
Greenboard drywall, compared to conventional drywall, shares the same gypsum core but differs in its outer covering and recommended usage:
Outer Covering: Greenboard’s outer paper covering is water-resistant but not waterproof. It is also treated with compounds that discourage mold growth. In contrast, conventional drywall’s outer paper facing is susceptible to mold when exposed to moisture over time.
Color and Identification: The outer paper cover of the greenboard is sea-foam green on one side. While this color does not provide additional water-resisting properties, it serves two purposes: it identifies the drywall as moisture-friendly, and it helps installers remember which side should face outward during installation.
Installation: Installing greenboard is very similar to installing conventional drywall. Panels are attached directly to framing members using drywall screws or nails. However, care must be taken during installation, as the paper facing on the green board is slightly more fragile than that on conventional drywall. Some professionals prefer to use closer spacing between nails or screws for better security.
Ceiling Installation: Some professionals advise against using green board on ceilings because the paper facing is less secure and the panels are heavier than conventional drywall. For bathroom ceilings, many professionals still opt for conventional drywall.
While green board and conventional drywall share the same gypsum core, the differences in their outer coverings make green board more suitable for areas prone to moisture, like bathrooms, where it helps prevent mold growth. However, for ceilings and other areas where weight and installation considerations are critical, conventional drywall may still be preferred by professionals.
Are Green Boards Allowed for Wet Applications?
Greenboard and other water-resistant drywall panels are technically approved for use in wet applications. According to ASTM C 1396, Section 7, water-resistant drywall can be installed in wet locations such as behind tile in bathtubs or shower stalls. The standard ASTM C473 specifies that after two hours of water immersion, the average water absorption for these panels should not exceed 5 percent by weight.
However, it’s important to note that local regulations can override national standards. Many communities prohibit the use of greenboard and similar water-resistant drywall for wet applications, despite its ASTM approval. Therefore, it’s crucial to always check with your local building inspection office to ensure compliance with local codes when selecting materials for wet areas.
When using greenboard or other water-resistant drywall for ceilings, caution is advised. Ceiling panels may sag under high humidity conditions or when exposed to finishing materials that contain moisture. For ceilings, many professionals continue to recommend conventional drywall as a more reliable option.
Alternative Materials for Wet Locations
When it comes to wet locations like showers and tub surrounds, there are alternative materials to water-resistant drywall (greenboard) that offer better performance and durability.
Cement-Based Backer Boards
Cement-based backer boards such as Durock, Wonderboard, and Hardiebacker are mineral-based or cementitious materials. These boards are designed to be used as a tile backer in wet applications due to their superior moisture resistance.
When combined with a waterproofing sheet or coating, cement board is perfect for tile-covered surfaces in showers and tub surrounds. It is also commonly used behind kitchen backsplashes and on bathroom walls outside the shower. Additionally, cement boards can serve as a base for tile flooring.
One advantage of cement board is its robustness as a tile backer, but it cannot be used as a surface wall panel and painted.
Glass Mat Panels
Glass mat panels, such as DensShield, are gypsum-based panels that replace the paper facing with a fiberglass surface layer. This fiberglass layer makes the panels entirely waterproof and highly resistant to mold. Unlike water-resistant drywall, glass mat panels do not require an additional waterproofing layer, which makes them quicker to install. This feature has made them increasingly preferred by professionals.
DensShield and similar glass mat panels can also be painted, making them a viable choice for non-tiled walls in areas like bathtub alcoves that are subject to splashing water.
Where to Use Green Board Water-Resistant Drywall
Greenboard drywall is best suited for areas that are prone to lightly damp conditions, humidity, and occasional minor splashes of water. It is suitable for the following locations:
- Bathrooms: Specifically, areas outside of shower and tub alcoves.
- Basement Walls: These areas can be prone to mold and mildew.
- Kitchens
- Laundry Rooms
- Garages
DO NOT Use Green Board in These Spaces:
- Saunas and Steam Rooms
- Shower Stalls
- Rooms with Spas or Pools
- Ceilings
For tile backing material in wet areas such as showers or tub alcoves, it is recommended to use cement board (combined with a moisture barrier) or glass mat panels. Greenboard can sag and fail when subjected to prolonged wet conditions.
Drywall and Green Board Installation Services
If you need help installing water-resistant drywall or completing any home project, contact your local drywall contractor in Pflugerville, Austin. You can reach us online or by calling (512) 293 9899. With years of experience, ROA Drywall in Pflugerville, Austin is your one-call solution for all drywall repair and installation needs.
FAQs
What is the name for moisture resistant drywall often used in wet areas?
The name for moisture-resistant drywall often used in wet areas is “green board” or “water-resistant gypsum board.
Can moisture resistant drywall get wet?
Yes, moisture-resistant drywall can get wet, but it is designed to withstand moisture better than standard drywall. It has additives in the core and paper facing that make it more resistant to water and moisture absorption. However, prolonged exposure to water can still damage moisture-resistant drywall, so it’s important to address any water issues promptly to prevent damage.
What do the different colors of drywall mean?
The different colors of drywall indicate different types and uses:
- Gray or White Drywall: This is the standard drywall used for most interior applications. It is not moisture-resistant and is typically used in areas that are not exposed to moisture.
- Green Drywall (Greenboard): Green drywall is moisture-resistant and has a green paper covering that helps it resist moisture better than standard drywall. It is commonly used in bathrooms, kitchens, and other areas prone to moisture.
- Purple Drywall (Purpleboard): Purple drywall is also moisture-resistant and has a purple paper covering. It is designed to be mold-resistant and is often used in high-moisture areas like bathrooms and basements.
- Blue Drywall (Blueboard): Blue drywall is used in areas where moisture resistance and mold resistance are important but is typically used for plaster veneer applications, not for regular drywall.
- Fire-Resistant Drywall (Type X): Fire-resistant drywall has added fire-resistant properties and is used in areas where fire protection is a concern, such as around furnaces, in garages, and between living spaces.
These colors help to distinguish the different types of drywall and their specific uses in construction and remodeling projects.