Mold Resistant Drywall

Mold Resistant Drywall

The Partnership for Advancing Technology in Housing (PATH) is dedicated to accelerating the development and use of technologies that radically improve the quality, durability, energy efficiency, environmental performance, and affordability of America's housing.

PATH heralds the technologies with the most promise for making our homes more durable, stronger and more resource efficient.

Selected technologies have notable strengths in one or more of the following areas: quality and durability; energy efficiency; environmental performance; safety and disaster mitigation; and affordability.

I’ll highlight their selected technologies from time to time.

People are more concerned with mold today, as well they should be. Today’s homes are more airtight, thereby trapping more pollutants, like mold spores, inside.

It makes sense (and cents) to try to eliminate or minimize pollutants with building technology.

Here’s one on mold resistant drywall from NAHB Research:



Drywall manufacturers have in recent years become concerned with the mold issue in the home building industry. Mold in new residential construction is an issue for builders due to the additional cost of remediation, not to mention visibility with homebuyers.

An April 2005 article on www.gypsumtoday.com described a CertainTeed survey that found 55% of 1000 homeowner respondents expressing concerns about mold. For solid materials such as framing members, mold remediation revolves around cleaning and treating.

However, for drywall, cleaning may not suffice for drywall, leaving a more expensive effort of removal and replacement.

Mold growth requires moisture and a food source. Therefore, some gypsum board manufacturers have developed products with gypsum cores that will not absorb moisture as easily as typical gypsum board.

To reduce the risk of mold growth that paper facings can provide, a number of manufacturers, including U.S. Gypsum (Sheetrock® Brand Humitek®), National Gypsum (Gold Bond Brand XP), and Temple-Inland (Silent-Guard™ TS gypsum shaftliner), chemically treat the paper on both sides of the gypsum board. Some manufacturers eliminate the paper entirely. Georgia Pacific (DensArmor® Plus) replaces the paper with glass mat facings, while U.S. Gypsum (FiberRoc® AquaTough™) uses a gypsum-cellulose combination in their panels that doesn't require paper.

The current standard for mold-resistant characteristics of drywall is ASTM D3273 Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber. This standard measures the ability of the drywall product to resist mold and mildew growth under certain prescribed moisture conditions, and a number of manufacturers quote the performance of their products when tested to this standard.

The numbers achieved by the products mentioned in this discussion achieved between 8 and 10, with 10 being the highest rating and zero being the rating of standard gypsum board. It is important to note, however, that materials are tested for only 30days, so the standard does not address longevity of the mold resistance treatment.

Mold-resistant does not mean that mold cannot grow. Under the right conditions, mold can grow on almost any surface. These products limit the conditions which are prime for organism growth, reducing the chances for mold.

PATH Attributes:

Resists mold growth and helps to protect indoor air quality.

Resists deterioration of drywall exposed to moisture, and reduces maintenance and replacement costs.

Mold-resistant gypsum board can help to maintain good indoor air quality - thus providing homeowners with environmental benefits. It also should reduce the probability of costly remediation and litigation - benefiting builders and remodelers, as well as home owners.

The dimensions, installation methods, and finishing techniques are exactly the same as traditional gypsum drywall products. Typically, panels are nailed or screwed to the framing and finished with joint compound.