What Is Mold Resistant Drywall?

And does it really work?

Drywall mold


Urban78 / Getty Images

It would seem like a slam-dunk. You fear mold erupting in your home wherever moisture is prevalent—in the basement, bathroom, laundry room, etc.—so you buy mold-resistant drywall.

Mold resistant drywall is an innovation in this often static world of gypsum board, and manufacturers have been heavily pushing this on builders, designers, and homeowners. But what is it and is it worth the added expense to install it?

What It Is

  • Drywall that is marketed as having fewer conditions that contribute to the growth of mold. The organically derived paper facing of traditional drywall is the area that provides ready conditions for mold. 
  • Not guaranteed or warranted to be mold-free.
  • Contents: either gypsum core with fiberglass facing or homogeneous (no layers).
  • About 10 percent more expensive than traditional paper-faced drywall.
  • Different from greenboard in that greenboard still has that paper facing.

The Bottom Line

In brief, mold-resistant drywall still can grow mold, and with surprising vigor. Ironically, manufacturer warranties do not cover mold growth. 

However, it does have less of a propensity towards mold growth than traditional paper-covered drywall.

Mold resistant drywall is more expensive than paper-faced drywall, but not vastly so. Expect to pay about 10 percent more for this product.

No More Paper, No More Mold?

Mold and mildew growth have become a hot-button issue lately due to health concerns. Mold remediation companies deal with killing and covering over mold/mildew, but it's always best to prevent mold before it starts.

Instead of the traditional paper facing for the outer faces of the gypsum slabs, manufacturers make slabs that come in either of two forms:

  • Homogeneous: This means that the drywall is the same material through-and-through, with no layers. The issue of a cover becoming a mold farm is lessened because there is no cover. 
  • Fiberglass facing: This drywall has the same traditional gypsum core. A fiberglass mat substitutes for the paper facing. 

With both products, the theory is that mold does not have the chance to feed on the organic materials which comprise paper-backed drywall.

Not the Same As Greenboard

Greenboard is paper-backed drywall that has a light green "hospital" tint. Greenboard is often used for high-moisture areas such as showers, in which the greenboard is heavily coated with bathroom-quality paint or with cement board on top.

Greenboard is less effective at inhibiting mold than mold-resistant drywall. However, greenboard is less expensive than mold-resistant drywall.

Brands and Their Compositions

Each manufacturer has a different way of tackling the mold problem. This is how three companies do it:

  • Uniform: Some brands, such as USG's Fiberock Aqua-Tough, have a uniform composition of materials; in other words, they have no facing materials of any sort. This is a type of homogeneous drywall.
  • Mat-Faced: Other brands, such as Georgia-Pacific's DensArmor, have a gypsum core and fiberglass mat facings on both sides of the board.
  • Paper-Faced: Georgia-Pacific's ToughRock and Certainteed's M2Tech Moisture & Mold Resistant Gypsum Board still have 100 percent recycled paper facing. The only difference is that the paper is treated to resist the growth of mold.

And the Secret: Mold Can Still Grow

Mold, it seems, can grow under practically any condition. After all, mold spores have been floating around this earth since day one.

With that kind of enemy, no wall covering manufacturer will warrant that its product is mold-proof; only that its product stands a lower chance of growing mold and mildew than traditional paper-faced drywall does.

Georgia-Pacific expressly states in its warranty for ToughRock that it does not cover "Mold, mildew, fungi, bacteria or other similar conditions." 

However, it should be noted that G-P is not alone; other manufacturers state this in their warranties.

Additionally, keep in mind that solving the drywall problem is only part of it. As an example, once you have a flood that inundates a bathroom or basement, not just the drywall is soaked—the studs are, too. 

With houses that have experienced flooding, you can strip away all of the drywall yet still find an infestation of mold above the waterline.

Prominent Brands

Some companies that market this type of drywall are:

  • U.S. Gypsum (Sheetrock Brand Humitek, FiberRock AquaTough)
  • National Gypsum (Gold Bond Brand XP)
  • Temple-Inland (Silent-Guard TS)
  • Georgia Pacific (DensArmor Plus, ToughRock)
  • CertainTeed (M2 Tech)