Membrane roof - materials at interior side of vapor barrier?

November 3, 2017

Joanna Switzer

Sustainability Project Manager
Atkins

LEEDuser Basic Member

59 thumbs up

November 3, 2017

Hi all,

Based on BD+C reference guide, it appears all materials installed to interior side of vapor barrier need to comply. However, I am finding it challenging to locate roof underlayment/cover board selections that indicate they are LEEDv4 compliant (have TVOC testing / related certifications on file).

Has anyone else had luck locating more than 1 option for TVOC tested roof underlayment/coverboard for use in membrane systems?

thx

Post a reply

Calie Gihl

Design Engineer

LEEDuser Expert

19 thumbs up

November 26, 2017 - 1:55 pm

Hi Joanna,

I found these products which look like they might be what you're looking for... if not, can you provide me with an example you've already found?

https://www.gaf.com/Other_Documents/Green_Roof_Central/GAF_Green_Building_Playbook_LEED_v4.pdf

https://usa.sarnafil.sika.com/en/group/roofing-sustainability/green-building-programs/roof-leed-usgbc/roof-leed-v2-usgbc1.html

Joanna Switzer

Sustainability Project Manager
Atkins

LEEDuser Basic Member

59 thumbs up

November 27, 2017 - 10:05 am

Calie,

Thanks so much. As of this moment, I've found a couple Green Guard Gold certified options USG (thus qualifying for the TVOC reporting requirement), but as noted in Sika/GAF info you shared most manf websites don't indicate this info is available, merely stating their "exterior" products are exempt. Hopefully in time that will change....more industry options are needed for optimal competitive bid specifications use.

USG

https://www.usg.com/content/usgcom/en/products-solutions/products/roofing/roof-boards/usg-securock-glass-mat-roof-board.html

National Gyp

https://spot.ulprospector.com/en/na/BuiltEnvironment/Detail/31734/712031/DEXcell-Cement-Roof-Board?st=1&sl=53557649&crit=a2V5d29yZDpbcm9vZiBib2FyZF0gPiBHUkVFTkdVQVJEIEdvbGQgQ2VydGlmaWNhdGlvbg%3d%3d&ss=2&k=roof|board&t=roof+board

Dawn Garcia

Marketing Communications
Roseburg Forest Products

LEEDuser Premium Member

10 thumbs up

December 6, 2017 - 8:39 pm

Hello Joanna - A new LEED interpretation (10466) has opened this up for additional materials to comply with the Low-emitting materials requirements. https://www.usgbc.org/leedaddenda/10466

You can now look for APA rated structural plywood sheathing products as they are not required to show separate VOC emissions testing.

Joanna Switzer

Sustainability Project Manager
Atkins

LEEDuser Basic Member

59 thumbs up

December 7, 2017 - 12:49 pm

Thanks Dawn! This is helpful as a general point of reference.

However, I have not yet found any exemption clarified for gypsum based substrate/cover boards, nor insulation / accessory products in cases where a vapor barrier is omitted. Likewise, have had no luck finding TVOC compliant/tested selections of these products to date. Frustrating given the potential for time lapsed VOC migration into the bldg. interior through all material layers located above the metal deck structure seems infeasible.....