Insulating a home in Zone 6a

A homeowner renovating a 1980s house in upstate New York asked a building-advice forum for feedback on an insulation plan for a cold climate (the kind of winter weather zone covering much of upstate NY and similar regions). The goal is to cut heat loss and hold down fuel costs without using spray foam.

The plan has three parts. For the exterior walls, framed with 2x6 lumber, the homeowner wants to fill the cavities with Roxul (a mineral-wool insulation) and cover the inside face with a vapor-permeable membrane such as Intello Plus, which blocks air leaks while still letting moisture pass through so the wall can dry out. The same approach would go into the angled cathedral ceiling sections. For the attic, which is unconditioned and vented to the outside, the plan is Roxul on the attic floor topped with blown-in cellulose, and the homeowner is also asking whether Roxul batts with baffles (channels that keep roof vents clear) or rigid Roxul board could work installed directly over the ceiling joists.

This is a homeowner seeking input from other builders and energy-efficiency specialists on an online forum, not a finished project or a verdict on the approach. No replies had been posted yet. For anyone doing a similar renovation, the underlying questions are the same ones this homeowner is raising: whether mineral-wool batts paired with a vapor-permeable membrane suit a cold-climate wall and ceiling assembly, and how best to layer insulation in a vented attic without blocking airflow at the roof edge.