There’s more than one way to build a highly insulated, air-tight house—or to tighten up and super-insulate an existing home. Here’s a look at an evolving array of superinsulated details that don’t use spray foam. More
Working around existing attic insulation to seal air leaks may be more cost-effective than removing and replacing it More
It makes as much sense keeping the summer heat out as keeping the winter heat in. More
I understand that fiberglass batt insulation can allow air to move through it and that this air movement degrades the insulation's R-value. Two causes I've heard about are wind-washing at the eaves and convective loops that can start in a wall cavity on really cold days and wick warmth from inside to the outside wall surface. But recently I have taken pains to do a very good air-sealing job on everything I build, whether it's an addition or a new house. I'm getting blower-door readings of less than 1.5 air changes per hour at 50 pascals. I also use baffles at the eaves, and seal the sheathing to the framing before insulating. Under these conditions - with air movement cut to a minimum - will fiberglass insulation perform at its stated R-value? More
Q: I built a lot of homes in upstate New York in the 1980s using 2x6 studs, fiberglass batts, and a poly vapor retarder for the shell. Given the rising cost of heating and cooling, the owners are asking about energy upgrades to their walls. I'd like to suggest adding 1 or 2 inches of rigid foam on top of the existing OSB or plywood sheathing, followed by new siding. Would the presence of polyethylene vapor retarders make this a risky retrofit strategy? More
Q: Is the flash-and-batt technique - where an inch or two of spray-foam insulation is applied to the interior side of roof or wall sheathing before fitting rafter and stud bays with fiberglass batts - a good way to insulate? More
Q: A house we built about eight years ago here in Tennessee has ductwork running through the space behind the upstairs knee walls. The exterior side of the framing has been developing condensation, but only in extremely cold weather. There are no vents in More
