Mapping out the roof assembly for a new house in Climate Zone 6B, Steve Mackay has settled on long I-joists insulated with a mix of closed-cell spray polyurethane foam and blown-in fiberglass. He doesn’t plan on venting the roof, and he wants to be certain his design will be problem free. Here’s what it looks like: 14-inch I-joists with 5 inches of closed-cell foam sprayed on the underside of the roof desk. The balance of the insulation will be fiberglass (Mackay wants to use the BIBS system) with no interior vapor barrier. In all, he gets R-67 in the roof…

What is a Living Building? A Living Building is rooted in place yet harvests all it needs, including energy and water. It is adapted to its climate and to its site. It operates pollution-free. It is comprised of integrated systems. And, it is beautiful.In this episode of the Green Architects’ Lounge, Phil and Chris discuss the Living Building Challenge (LBC), a certification program that aims to transform the marketplace, with all its joys and challenges. Collaborating for the first time, their firms are working on a LBC project, The Ecology School in Saco, Maine. On the show, Phil and Chris…

This is a story. Much of this story I believe to be true, but I can’t document much of it either. It all just makes sense, particularly as parts are conveyed by Bill Rose, our industry’s heralded building-science historian (see #2 in Bill’s to-do list for the building industry). Much of the story is based on one or more conversations I have had with Bill, which usually started something like this: “Bill, where the hell do the units 1 grain of water and 1 in. of mercury vapor pressure come from in our unit of measure for water vapor permeance?”…

Editor’s Note: This is one of a series of blog posts by David Goodyear describing the construction of his new home in Flatrock, Newfoundland, the first in the province built to the Passive House standard. You’ll find his complete blog here. It is now May. The weather is shaping up, and after a long, cold winter the ground is starting to thaw. Old Man Winter did give me one thing this year: a lot of time to think. I have been thinking mainly about food security and accessing more locally grown food. We had a successful harvest last year and…

Critics say efficiency testing rules for manufacturers of home appliances would be loosened under a Department of Energy proposal. The DOE has refused to schedule a public meeting to explain the change but has offered private meetings as an alternative. Photo: Phillip Pessar / CC BY 2.0 / Flickr The Department of Energy (DOE) has proposed a rule change that would allow appliance manufacturers to opt out of energy efficiency testing, seriously undermining U.S. efficiency standards, an advocacy group claims. The DOE billed the proposal, which was published in the Federal Register on May 1, as an effort to streamline…

Two years after fire roared through a public housing tower in London and killed 72 people, the type of insulated cladding thought to have contributed to the blaze is still a threat to thousands of British apartments dwellers, according to published reports. The fire at Grenfell Tower reportedly started with a faulty refrigerator in an apartment on a lower floor and spread rapidly up the outside of the 24-story building. Investigators believe that an aluminum-faced cladding with a core of polyethylene insulation helped make the fire so deadly. The panel, called Reynobond PE, was installed over an air gap that…