Reducing thermal bridging
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| Posted in Energy Efficiency and Durability on
I represent a PU injected SIP company (Eco-Panels) that uses an imbedded cam-lock system and has patented structural fully insulated corners. With our system, we significantly reduce thermal bridging, but still face the challenges of using standard framing materials for pre-framed window and door rough openings and bottom and top plates. Can any of the professionals on this site provide me with some alternative structural materials that increase overall thermal performance whether it be reducing thermal bridging or increasing R-value?
Thanks,
Craig T. Payne
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Replies
i've seen some 'thermal' 2x4 and 2x6 lumber offered: rstud.com
couldn't tell ya how it works
on the jobsite i've seen a sort of stacking approach of layering plywood and xps insulation to form lumber like pieces
Something cheaper than Rstud (for 6" walls) would be to inlet a pair of 2x2s. With PU SIPS, this has an added advantage of routing out less material. On larger openings, then case it all with 1/4" plywood. The plywood gives back torsional rigidity without sacrificing much thermal bridging.
The manufacturer's drafting dept. should be able to draw it up.
I once installed SIPs on a Wisconsin home that had a stepped foundation, such that the SIPs rested on something like a brick ledge below the bottom of the joists. This was a post and beam house and the SIPs were not structural, and I'm not an engineer so I wonder: if both joists and wall are anchored to the foundation, but not to each other mechanically, is there any reason this approach wouldn't work for all homes? Seems a pretty slick way to address air sealing and insulating one of the most problematic parts of western platform building.
Thanks for the replies. The main reason I posted this question is because Eco-Panels is receiving many inquiries about our 8.5" R-60 PU panels for Passivhaus Certifications. Obviously reducing thermal bridging is a big deal for Passivhaus.
David, your approach does work for panels whether structural or curtain wall, but I don't know for conventional framing.