Updating the attic of an existing older home is bread-and-butter business for Matt Damon and Paul Shepherd, the owners of Penobscot Home Performance, in Bucksport, Maine. In May, JLC stopped by a jobsite in Rockland, Maine, to see the company’s crew building and installing an insulated hatch in the attic.
The full attic job included removing all the existing fiberglass insulation, sealing up all the typical leaks (including partition-wall wiring penetrations, recessed lights, bath fans, and a chimney chase), and then blowing an R-60 blanket of cellulose insulation into the lid. “We blow at 18 inches depth, and it settles to 16,” explained Matt Damon.
Retrofit standards in Penobscot’s market call for an airtight attic hatch that roughly matches the insulation value in the rest of the attic. Over the years, Damon, Shepherd, and their crews have worked out a solution: a lightweight panel door with a handle in the center, topped by several 2-inch layers of rigid insulation (either polyiso or extruded polystyrene), for an R-value of about 40.
“We put a 1x2 ledger around the opening, and we kerf in a weather strip for airtightness,” said Damon. To gain access to the space, the homeowner pulls down the existing access ladder, grasps the door by the handle, and lifts it up. To secure the closed door, the owner dogs it down with window sash locks installed at both ends.
“The design has evolved over time,” Damon said. “We used thicker plywood for some of the first ones we made, and those doors were kind of heavy and hard to lift. Now, we use thin AC plywood, or even lauan. We used to use hook-and-eye hardware to lock the doors down, and we’ve found that the window sash locks are easier to use and work better.”
The Penobscot crew tests its jobs with a blower door on the way out, to make sure each job is meeting program targets. The attic hatches are “super tight,” Damon said. “Once in a while, if the caulking detail around the ledger isn’t perfect, you can get a little air coming out. Then the guys go back and do what we have to do to fix it and tighten it up.”
