Finally i made the main insulated attic stair box cover.
Build attic stair insulation box.
The shield holds the insulation to the box.
Add insulation to the exterior of the plywood box.
Attach the foam box to the floor with metallic tape.
Cut sides and top from sheets of 3 4 foam board with a utility knife.
More insulation 6 inches or 8 inches isn t uncommon.
That means that you should glue at least 4 inches of foil faced polyisocyanurate r 26 to the box.
Much like attic stairs above when whole house fans are installed.
Position the box over the stair opening in the attic.
Installs easily without tools.
Insert the insulation into the reflective shield and place the stair cover rigid box into the reflective shield covering the insulation.
Whole house fans and ac returns.
I also made the box wider and longer than the attic stair opening so that i could install weather stripping on the bottom to create a tight seal.
With attic insulation we aim for a pretty high standard usually at least r 49 and the coffin insulation should match.
The box should rest squarely on top of the attic stairs frame or on wood stops installed to.
Additional insulation not included may be added to the sides or insulate the attic up to the sides of the stair cover kit.
Assemble the sides of the box with metallic duct tape.
Add the desired amount of insulation over the cover to restore the insulation removed from the ceiling.
Measure the size and height of the stairs from the attic.
An attic stair cover provides an air seal reducing the air leaks.
I made the box wider than the custom piece so it would fit over the first box.
The box is hinged on one side which makes.
Hinge the lid to the box on one side with metallic tape.
Attach the blanket insulation to the attic side of the cover box with adhesive and wrap it with building wrap or other air barrier to prevent air movement in the insulation from degrading its r value.
An easy low cost solution to this problem is to add an attic stair cover.
Insulated attic stair cover box.