This episode of the BS* + Beer show—with surprise guest Jake Bruton—tackles the topic of sheet goods as air barriers. The consensus is that, yes, sheet goods can make good air barriers, although there are many different approaches, and some are more reliable than others. The conversation covers how best to measure cubic footage, the origin of ACH50 as a standard measurement for air leakage (and whether or not using it is a logical approach), how to detail transitions and penetrations, selecting and air-sealing windows and doors, and much more.
Enjoy the show!
Join us on October 7 from 6 to 7:30 p.m. ET for a conversation around the topic “Photovoltaics: Harnessing Solar Energy Effectively.” Solar system designer Will Field from Revision Energy, Sam Brown, executive director of Clean Energy New Hampshire, and Joseph Berry of National Renewable Energy Laboratory will be our guest experts.
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Will Field grew up in Freeport, Maine, and graduated from Bates College with a degree in U.S. history. Will started in the renewable energy field as a solar installer and project manager before joining ReVision Energy as a system design specialist in 2017. Will enjoys the meaningful work of helping homeowners design and achieve their energy-transition goals, while working with a team of like-minded employee-owners in a challenging and often-shifting clean tech landscape. Outside of his work, Will focuses his passion, time, and energy toward the attempted mastery of stringed instruments, learning the craft of fine woodworking, reading nonfiction, running in the woods, and skiing. He lives with his partner Alison and adopted lab-mix Chip in Belfast, ME.
Sam Brown leads Clean Energy New Hampshire in its effort to create a cleaner, more affordable, and more resilient energy system in the Granite State. Sam grew up in the Lakes Region of New Hampshire. Prior to joining Clean Energy New Hampshire in 2021, he was a podcast host and radio journalist for nearly 10 years, during which time he wrote stories about New England energy issues; he won several regional and national awards for that work. Sam is also a bike mechanic, a Spanish speaker, and a father of two. He graduated with a B.A. from Bates College in politics and spanish in 2009.
Joseph Berry a Senior Research Fellow at the National Renewable Energy Laboratory working on halide perovskite solar cells. He has experience across multiple photovoltaic technologies as well as doing work in other energy technologies (e.g., light emitting diodes). His efforts at NREL emphasize relating basic interfacial properties to relevant device level behaviors in traditional and novel semiconductor heterostructures including oxides, organics and most recently hybrid semiconductors. He is also a principal investigator on the NREL lead Department of Energy, Solar Energy Technology Offices “De-risking Halide Perovskite Solar Cells” program as well as being the director of the US-Manufacturing of Advanced Perovskites (US-MAP) Consortium and a Fellow at RASEI a joint energy institute between the University Colorado Boulder and NREL.
Kiley Jacques is senior editor at Green Building Advisor. She can be reached at [email protected]. Photo credit: Tim Furlong Jr.
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Can someone share the link that Travis put into chat box for sealing big box door thresholds gone bad?
Also, any idea what size backer rod Jake slides into the factory door seals? 1/4"?
Usually backer rod is just a bit bigger than the opening. So if you have a 1/4" construction gap, you'd want a 3/8" backer rod. If you're using European-style gaps of 1/2", you'd want 5/8" backer rod.
Thanks Mike! #askmike
I watched the episode about a week ago, but I think I remember that Michael mentioned that he uses taped plywood as an air barrier for his double stud houses. I'm thinking about using this approach on my own double stud house next year.
We hear so much about high performance wrb's/ air barriers, but is that necessary with your approach? Or is taped plywood considered high performance? If it is, could you then just use Tyvek as a wrb? Seems like it would be a cost effective way of doing it.
Adam, I specify several different approaches, depending on the situation, and when building projects myself I like trying different techniques. But for a few years now my preference for double stud construction has been taped CDX as the primary air control layer. I also like Huber's Zip System, but double stud walls can get damp sheathing in late winter/early spring, and from what I've seen, plywood holds up better than OSB to repeated wetting, and researchers say plywood's permeance when wet is higher than OSB's, which facilitates drying. You do need to deal with surface voids in the plywood veneer; builders I work with have used caulking or additional tape for that. Tyvek is high permeance; I prefer Typar, which is around 12 perms, which I prefer with the reservoir claddings I usually use, as it helps protect against solar vapor drive.
The tightest house I've designed with double stud walls and taped CDX as primary air control tested at 0.12 ACH50, built by Emerald Builders. It also had taped Mento on the exterior and taped Intello on the interior, but the shell test showed that the taped sheathing was doing its job.
Even better than plywood would be solid sawn boards with a fully adhered WRB. My friends in Vermont such as Robert Swinburne and Gero Dolfus at Mindel and Morse Builders use that approach. I have a couple of projects going now with board sheathing but it's less common here in Maine, and probably even less common elsewhere.
Thanks very much for the thorough reply, Michael. You've echoed some points that I've already come across on GBA. I'm also planning on including Intello, so hopefully that helps in achieving a low ACH. One thing I hadn't considered was the vapor drive with reservoir claddings and plywood surface voids. I'll keep those in mind!
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