A low-slope roof pitch doesn't leave much in the way of
navigable attic space above a flat ceiling. That doesn't
prevent use of the void for duct and wiring runs, and it
doesn't affect the requirement for a scuttle for service
access. But, because the ceiling joist bays are typically piled
with itchy batt or blown-in insulation that buries the joists,
human crossings are at best unpleasant.
Chatham, Mass., builder Chip Hardy solves this problem and
reduces his scrap pile at the same time by creating a crawl-way
above the attic insulation.
After snapping a guide line down the attic's length, he uses
construction glue and toenails to fasten 18-inch-long 2x4 riser
blocks, on edge, to the top edge of the joists. He decks over
the top of the blocks with plywood scrap of varying thickness
— whatever's left after decking and sheathing.
Given a minimum ceiling joist depth of 2x8, the risers create
an 11-inch-deep bay under the crawl, with negligible effect on
the insulation's thermal value. Hardy's hvac contractors are
particularly pleased with this provision, and he figures he'll
be patting himself on the back when the time comes for him to
service a gable vent, chase a wire, check a duct, or perform
some other future task. — Dave Holbrook