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NC-2009 MRc4:Recycled Content

"Special" coating requirements for recycled content GWB.

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Charles Fritzemeier
Architect
Tetra Tech Architecture & Engineering
LEEDuser Basic Member
2 thumbs up

I have a situation where our client is very concerned that GWB with recycled content needs to be specially sealed in order to maintain a healthy environment. Because of this concern, we have been asked not to use recycled content GWB and to use conventional GWB "because it is healthier". Two questions: 1) is this concern valid? (or is it simply based on the sulfurous GWB imported from China several years ago); 2) is a special, additional sealer coat needed for recycled content GWB (Kilz, etc.)?

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Barry Reid
Building Envelope Technical Manager
Georgia-Pacific LLC
LEEDuser Basic Member
6 thumbs up

Thu, 08/09/2012 - 16:47

#1) Concerns over the safety of “Synthetic” gypsum are unfounded. Synthetic gypsum (which is the recycled content in GWB) is chemically identical to natural ore. Natural gypsum ore (a did you know?) is approved for use as a food additive by the FDA. #2) There is no need for an additional sealer coat on any wallboard, except when specific aesthetic concerns relating to finished appearance are an issue.

Mon, 09/17/2012 - 19:18

There are concerns with the mercury content in synthetic gypsum board made with waste materials from coal fired power plants. I'm unaware of there being special sealers that can mitigate the mercury content.
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Tristan Roberts
Representative
Vermont House of Representatives
LEEDuser Expert
7780 thumbs up

Mon, 09/17/2012 - 19:36

I agree with Barry—concerns about mercury in synthetic gypsum are off the mark. IF there is mercury, available evidence says there is very little, and there is no exposure route to affect occupants. Better off spending your time on things that truly affect occupants, like emissions from coatings, carpeting, furniture, etc. Adding a sealer in a situation like this would introduce VOCs that don't need to be there.

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