Attic Access Panels/Doors/Stairs

Good air-sealing and a continuous air barrier between the attic and the home’s conditioned (living) space are important, not only to save energy and reduce fuel bills, but also to prevent moisture problems in the attic. Sealing holes in the attic ceiling reduces the house’s “suction” (or stack effect) so less contaminants are drawn up into the house from the ground such as radon and other soil gases (Lstiburek 2010). Openings used for access to the attic such as access panels, doors into kneewalls, or dropdown stairs should be air sealed and insulated.  To air seal, weather stripping should be added to either the frame or panel of the attic access panel or door and latch bolts or mechanical fastener should be installed that will pull the access door tight to the weatherstripping for an airtight seal. To reduce heat loss, these access panels, doors, or stairs should be insulated. Panels and doors can be insulated by gluing rigid foam to the panel or attaching batt insulation with bolts and wiring or metal strapping. Pull-down stair kits can be purchased with rigid insulation already attached to the panel Alternatively some pull-down stair kits come with rigid insulation already attached to the inside of the back door panel, between the panel and the stairs. Or a rigid foam box-shaped cover can be constructed or purchased that fits over the stairs and is lifted and placed out of the way when accessing the attic.

The insulated and gasketed attic cover might be installed by the framer or the insulation contractor. This task should be included in the contract for the appropriate trade depending on the workflow at the specific job site.

How to Air Seal Attic Access Panels

1. Install wood trim pieces on the ceiling side of attic access hole framing. The trim should extend one-half inch to one inch around the inside edge of the access hole forming a ledge. The access panel will rest on this trim.
2. Install weather stripping along the top of this ledge.
3. Cut the access panel with even edges and one-quarter inch to one-half inch of clearance around the edges.
4. Insulate the top of the access panel with rigid foam or fiberglass batt insulation that is glued or fastened with bolts and wires to the panel.

Figure 1 - Air seal the attic access panel with a continuous gasket of weather stripping

How to Air Seal Attic Pull-Down Stairs

1. Install 1x2 or 1x3 wood trim pieces to surround the inside edge of the access hole framing. When closed, the back panel of the stairs will be rest up against this trim, so recess the trim enough to ensure the back panel will be flush with the ceiling.
2. Install weather stripping along the bottom edge of this trim or along the inside top edge of the back panel to act as a continuous gasket.
3. Install additional weather stripping along the top of this trim to provide air sealing for a box-shaped cover that will insulate the stairs.
   a. Construct or purchase a box made of rigid foam insulation sized to fit the access hole. This box can be lifted and placed out of the way when accessing the attic. Additional batt insulation can be attached to the top of this box if desired.
   b. Alternatively some pull-down stair kits come with rigid insulation already attached to the inside of the back door panel, between the panel and the stairs.
4. Add 1x8s or plywood strips cut to desired height to each side of the drop-down stairs framing to act as insulation dams to keep blown-in attic insulation from falling into the stairs. 

Figure 2 - Air seal the attic access pull-down stairs opening with weather stripping and construct or purchase a rigid foam box to insulate the opening

How to Air Seal an Attic Door

1. Install weather stripping along the inside door frame and threshold.
2. Install a latch that will pull the door tight to the frame and the weather stripping. Do not undercut the door.
3. Insulate the attic side of the door by gluing rigid foam to it or attaching batt insulation with screws and wire. glued into place.

Figure 3 - Air seal the attic kneewall door opening with weather stripping and insulate the door panel

How to Air Seal an Attic Kneewall Drawer or Closet

1. Build framing for the drawer or closet box.
2. Insulate the framing rigid foam.
3. Line the box with drywall, OSB, or plywood that is caulked at the seams.

Figure 4 - Build an airtight box around any drawers or closets built into attic knee walls that extend into uninsulated attic space. Insulate along air barrier (shown in yellow on drawing). Caulk at seams (red dots).