The Ultimate Guide to Choosing the Right Drywall for Your Bathroom and Basement
Jason Lebeau from MrWalls Drywall & Painting
Jason has been a drywall contractor for 25 years. He is the owner of MrWalls Drywall & Painting in Chicopee Massachusetts, and still works in the field daily.
Choosing the Right Drywall for Your Bathroom and Basement. A guide for homeowners planning a bathroom or basement remodel. Moist areas require special drywall boards.
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The Ultimate Guide to Choosing the Right Drywall for Your Bathroom and Basement
When you are remodeling your bathroom there comes a time when you have to Install the drywall. Your standing in the lumber aisle of a big-box store picking up drywall, it all looks pretty much the same: big, heavy, dusty sheets of grey, green. purple and even some that looks like cement. But picking the wrong "type" of gypsum board for your project is a mistake that usually smells like mildew and ends in a demolition crew. This guide goes over the type of drywall to use in your bathroom remodel and why.
Standard drywall is essentially a sandwich of pulverized rock and paper. In a dry bedroom, it's perfect. In a damp basement or a steamy bathroom? It’s basically a snack for mold. Here is how to pick the right board for the high-stakes areas of your home.
1. The Bathroom: Managing the Steam
Bathrooms are localized tropical environments. Between the shower steam and the occasional "oops" from the tub, your walls are under constant hydraulic attack.
Greenboard (Moisture-Resistant): This is the classic choice for bathrooms. The paper facing is treated with wax for water resistance. It’s ok for the "dry" areas of a bathroom like the walls and ceilings outside the shower.
Purple Board: If you want to level up, Purple board offers the same moisture resistance as Greenboard but adds mold-resistant properties to the core and the paper. Many stores only carry the moisture and mold resistant variety for a good reason, go Purple.
Cement Board:Ok if your shower isnt getting a vinyl wall kit, Do not put Greenboard or Purple board inside a shower stall as a tile backer for a tub surround. For areas in direct contact with water, you need cement board (Cement Board, HardieBacker, or WonderBoard). It won't rot, warp, or disintegrate when wet. For the best tile installation seal that cement board with Red Guard. It is a water proof membraine that gets applied in 2 thick coats with a paint roller.
2. The Basement: Fighting the "Below-Grade" Blues
Basements are notorious for "wicking" moisture through concrete foundation walls. Even if your basement feels dry today, a heavy rainstorm can change the humidity levels in hours.
Paperless Drywall (Fiberglass Mat): Standard drywall uses paper facing, which is organic "food" for mold. Paperless drywall replaces that paper with a fiberglass mat. It’s slightly itchier to install and requires a full skim coat to get a smooth finish, but it’s virtually mold-proof if you use the matching joint compound that goes with it and mesh tape.
Type X (Fire-Rated): If you are finishing a basement utility room in a condo or townhouse, check your local codes as you likely need 5/8 type X drywall on the walls that butt up to other units. Type X drywall is usually required in garages as well, It’s 5/8-inch thick and reinforced with glass fibers and a special blend to slow the spread of fire. There is no rule against using type x everywhere in your home for added fire protection. They also make type x in the purple moisture and mold resistant variety but you will have to special order it from the lumber store. All specialty drywall supply stores carry the 5/8" type x in both regular and purple variety, so see if you have one in your area.
3. Installation Tips for Damp Areas
Mind the Gap: When hanging drywall in a basement, leave a 1/2-inch gap between the bottom of the sheet and the concrete floor. This prevents the drywall from "wicking" up any water if the floor gets damp. Baseboards will hide the gap.
Use the Right Screws: For high-moisture areas, use galvanized or specialty coated drywall screws to prevent rust heads from bleeding through your paint.
FAQ: Choosing Your Sheets
Q1: Can I just use regular drywall if I use "mold-resistant" paint? No. Mold-resistant paint is a great secondary defense, but if moisture gets behind the paint or seeps in through the outlets, standard drywall will rot from the inside out. Don't cheap out on the substrate.
Q2: Is Greenboard waterproof? No. It is water-resistant. If you submerge Greenboard in water, it will fail. It is designed to handle high humidity, not direct saturation.
Q3: Why is Purple board more expensive than Greenboard? Purple board (specifically from National Gypsum) is tested to handle both moisture and mold growth. It’s an all-in-one insurance policy for your walls. In a small bathroom, the price difference is usually less than $50 for the whole room, well worth it.
Q4: Can I use fiberglass mat (paperless) drywall in my bathroom? Absolutely. It’s actually a superior choice to Greenboard or purpleboard. The only downside is that it has a slightly textured "orange peel" finish due to the fiberglass, so it requires a skim coat if you want a perfectly smooth "eggshell" paint finish.
Q5: What thickness should I buy? For most residential surfaces, 1/2-inch is the standard. If you’re doing a ceiling where the joists are 24 inches apart, or if code requires type x, go with the 5/8" type x to prevent the "sag" and to meet the building code.