Question

Does drywall, U.S.-made, outgas? Also, is it termite and mold resistant?

Asked by Eva
San Luis Obispo, CA

I want to replace paneling in a mobile home with drywall. It is a small mobile home and I am highly sensitive to chemicals and outgassing. There are always termites here in California, and when it rains heavily the mobile home is very sensitive to moisture. I don't want mold growing on the drywall.

Answer

Cynthia Phakos

Answered by Cynthia Phakos

Los Angeles, CA

Koffka Phakos Design

May 12, 2011

A new material that seems to be perfect for your situation is EcoRock.

  • It is more expensive than standard drywall but it is not susceptible to termites or mold.
  • EcoRock is the most sustainable option of all of the materials I mention below.
  • Something I did not know until recently is that “drywall is the number three producer of greenhouse gases among building materials, trailing just behind cement and steel. Its production generates 200 million tons of carbon dioxide gas.” (Read the Inhabitat article on this subject here.)

EcoRock’s manufacturer, Serious Materials, lists a number of sustainable aspects of the EcoRock on their website, from energy savings, to recycled content, to mold resistance and additional indoor air quality considerations. 

What is drywall?

Drywall is made of gypsum plaster pressed between two thick sheets of paper.

The paper facing is susceptible to water and the gypsum, being porous, will support mold growth.

According to eHow.com, “gypsum plaster is made from gypsum, which is naturally formed when sea water evaporates and leaves mineral deposits (calcium sulphate and water). The layers of gypsum are excavated, fed into a crusher, and then ground into a fine powder. It is then heated to evaporate the remaining water molecules. This is an energy-intensive process.”

Drywall alternatives

Alternatives to the paper-faced drywall, commonly used in bathroom and wet room applications, are:

  • Greenboard. The moisture resistance comes from an oil-based additive in the green colored paper covering.
  • Blueboard. This blue face paper covering is water resistant and also forms a strong bond with a skim coat or a built-up plaster finish, which adds to its water and mold resistance.
  • Cement board. This alternative is more water-resistant than the above and is used in showers or sauna rooms, and as a base for ceramic tile.

All of the above options should be used with a skim coat of plaster finish, which will add to the cost of the application, and the sheets are also more costly than standard drywall.

Another, more economical option, is mold-resistant, paperless drywall.

  • In this case, the sheets of the drywall are faced with fiberglass instead of paper to prevent mold growth.
  • I did read on a builder’s blog that when painted, in the right light the texture of the fiberglass can be seen.
  • Also, it has a rougher texture than paper-faced drywall.

 

For more information:

Read "Is there such a thing as green drywall? If so, what alternatives to conventional drywall do you recommend?" a Q&A answered by Mary Cordaro.

Tagged In: home air quality, drywall

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