Green board drywall is a popular moisture-resistant drywall. Manufacturers created green board drywall to address the challenges of high humidity and occasional water exposure on interior surfaces. Green board drywall is not water-proof, but its unique water-resistant features give it more protection against all issues related to water including mold, mildew, and deterioration.
The distinctive green paper color sets green board drywall apart from standard drywall, serving as a visual reminder of its moisture-resistant characteristics. Understanding the qualities, benefits, and best practices surrounding green board will allow you to utilize this valuable resource in your home building projects.
What is Green Board Drywall?
Green board drywall is a type of gypsum wall panel that manufacturers design to withstand higher levels of moisture and water exposure. Builders commonly use it in high-humidity areas like bathrooms, kitchens, and basements.
The term “green board”, also written as “greenboard”, refers to its distinctive green color because of the green paper facing on one side of the panel. This green paper facing is treated with waxy additives that make it more resistant to moisture absorption. This treatment helps preserve the paper from growing mold, mildew, and deterioration from water. Green board drywall has a standard gypsum core which gives it natural fire resistance.
Using Green Board Drywall vs. Standard Drywall
Green board is especially useful in moisture-prone areas of the home. Its unique qualities make it a better choice in these rooms.
- Bathrooms – Due to the presence of moisture from sinks, showers, and bathtubs, bathrooms are ideal for green board drywall versus standard drywall. Installing green board drywall will prevent the growth of mold and mildew from the high moisture.
- Kitchens – Kitchens are another high moisture area because of the possibility of water spills and leaks. Green board drywall can add protection to ensure that your walls will not deteriorate with water exposure.
- Basements – Basements have higher humidity levels because they are below ground. Green board drywall can help to mitigate the growth of mold and mildew that is common in basement rooms.
- Laundry Rooms – Laundry rooms are subject to spills and leaks. Green board drywall offers better defense against possible water exposure.
- Utility Rooms – Utility rooms that house water heaters, utility sinks, and boilers may suffer water leaks. To better protect against these, add green board drywall rather than standard drywall.
- Garages – Garages may benefit from green board drywall if you use them as a multi-purpose space that has water exposure.
- Crawl Spaces – Crawl spaces are located below the ground surface and are prone to high humidity. Using green board drywall will protect the walls from deterioration.
Cost of Green Board Drywall
Green board drywall is more expensive than standard drywall because of its speciality components and production. Standard drywall costs $0.40-0.50 cents per square foot. Green board drywall costs between $0.50 and 0.70 cents per square foot. A standard 4 foot x 8 foot green board drywall panel costs anywhere between $12-20 dollars depending on the supplier and location. Sometimes, building supply stores will offer a bulk discount for drywall orders over 48 sheets.
Green Board Drywall Sizes
Green board drywall sizes, similar to standard drywall sizes, are varied to accommodate projects of different scopes.
Length and Width
- 4’ x 8’ sheets – This is the most common size for green board drywall panels. Builders use it for wall construction.
- 4’ x 10’ sheets – These sheets are 4 feet wide and 10 feet long. The longer panels are useful in large rooms and for reducing the number of seams.
- 4’ x 12’ sheets – 4’ x 12’ sheets are not as common but are useful for the walls in rooms with high ceilings or where seam reduction is required.
- Specialty sizes – Other sizes are possible but not common. Availability will depend on the particular manufacturer and area.
- ½” – ½” thick sheets are the most common standard thickness for green board drywall. It is suitable for most interior walls and provides a good balance between strength and versatility. This thickness provides good moisture resistance.
- ⅝” – This sheet is used in primarily commercial spaces where extra moisture resistance, fire resistance, and strength are needed.
Limitations of Green Board Drywall
Green board drywall is not the answer to all of your moisture-related concerns. It does have limitations for its use that you need to consider before choosing it for your project.
- Not Waterproof – One of the main misconceptions that people have about green board is that it is waterproof – it isn’t. It is more moisture-resistant and able to handle occasional water exposure than standard drywall, but it is not suitable for places with direct and constant water exposure. In areas like shower enclosures or other wet areas, use cement backer boards or a water-proof membrane as a sublayer.
- Limitations in High Moisture Areas – Green boards are moisture-resistant. But in areas with constant moisture exposure, they may suffer some negative effects depending on the moisture level.
- Mold and Mildew – Green board has thick and waxy paper facings that prevent water from entering the gypsum core, but they are not specifically treated to resist mold and mildew growth. The development of mold and mildew may occur if water does reach the core and does not have a chance to dry out. The new varieties of mold and mildew-resistant drywall is a better option if your area has constant moisture exposure.
- Cost – Green board drywall is more expensive than standard drywall because of its treated paper facings. Though not a huge cost difference, the higher cost will have a greater impact on large-scale projects.
- False Sense of Security – Relying on the green board rather than addressing underlying problems or installing it in areas with too much water can lead to damage over time. It is important to ensure that your overall plan and construction methods to handle moisture are sound before installing green board.