A Better Roofing Membrane?

Patricia Heye

EHDD

LEEDuser Basic Member

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June 27, 2022

Hello,

We are having a discussion / a bit of a debate in our office about the merits and sustainability of different roofing materials. Our current standard is to use a PVC membrane, which we all know is highly toxic. TPO is an obvious alternative that is less toxic, but it has some performance concerns and can often lead to leaking (not a sustainable choice either), so it is not a product we typically recommend. Does anyone know of an innovative roofing material, or perhaps advancements in TPO, that would be a less toxic material for us to specify that still performs as needed?

Thanks!

Patricia

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Mike Manzi

Bora Architects

LEEDuser Basic Member

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Mon, 06/27/2022 - 18:29

Hi Patricia, I've been struggling with this question for years and am aware of no clear winner for low-slope roofing. HBN recently added roofing to their HomeFree guidelines: https://homefree.healthybuilding.net/products/72-low-slope-membrane-roofing-hazard-spectrum. While they suggest avoiding adhesives, our envelope consultants typically recommend fully adhered systems for better performance. We specify VOC and emissions criteria for adhesives. Given the terrible life-cycle aspects of PVC, we avoid unless forced to use by a client. I like the durability of a high-quality modified bitumen system, but this is obviously not ideal. We use a lot of TPO roofs, generally 80 mil, fully adhered. If installed properly, I don't think they should inherently lead to leaking, but I know how manufacturers of other roof systems like to describe TPO. If there have been frequent failures of the TPO roofs on our projects, we haven't heard about them. Mike Manzi RA, CCS, LEED BD+C Associate Principal he/him Bora Architecture & Interiors