How to Install an Attic Access Door

Measure the attic access door's sleeve length and width with a tape measure, if using a prefabricated access-door package. The sleeve extends from the door's trim moulding up into the attic area and acts as an insulation dam. The access door connects to the sleeve near the trim.

Locate an area on the ceiling between the rafters where the access door will have room. Rap on the ceiling from one wall to another. With a pencil, mark the first spot where the rapping noise changes tone. Drive a punch through the drywall at this spot. Use the punch to feel around above the ceiling for the rafter. You will know you have found it when the punch hits something solid. Lay out the first rafter on the ceiling with the pencil, using the punch as a guide. Locate the next nearest rafter using this method. Verify the access door will fit between the rafters in the room.

Lay out the length of the prefabricated access door or the length of a custom-made access door along the first rafter's edge. Make starting and stopping points with the pencil. Cut the ceiling between the marks using the edge of the rafter as a straightedge, above the ceiling the rafter will guide the saw blade.

Place the outside edge of a square on the rafter's cut and the angle on the start mark. Draw a pencil line to the next rafter using the square as a guide. Repeat this process for the stop-mark side of the rafter's cut.

Cut the ceiling along the second rafter's edge between the lines coming from the start and stop marks with a drywall saw. Cut the start line. Cut the stop line. To prevent the cutout from breaking, keep a hand on the drywall cutout while cutting. Save the drywall cutout.

Remove and save the insulation from above the drywall hole.

Secure the sleeve in the hole with a drill and the required screws. A prefabricated door's sleeve slides into a ceiling's cutout hole and screws directly to the two rafters with the manufacturer's recommended screws or bolts, often 1-inch lag bolts. Custom-made attic-access holes require a sleeve built from the access hole's actual measurements. The sleeve is held in place with 1 1/4-inch drywall screws.

Measure between the two rafters for the custom door's sleeve width. Cut two 1-by-8-inch boards this length with a circular saw. Cut two 1-by-4-inch boards the rafter-side opening length plus one and a half inches, the length of the opening plus the thickness of the two side pieces.

Measure and mark each end of each 1-by-8-inch board, the board that will fit between the rafters, 3 1/2 inches from the bottom. Place a "B" on the bottom, one of the long 1-inch-thick sides, for reference.

Screw the 1-by-4-inch rafter-side boards to the ends of the 1-by-8-inch boards with 1 1/4-inch drywall screws. Place them a half inch in from the 4-inch-wide board's end. The bottom of the 4-inch board should line up with the pencil mark on the 1-by-8-inch board's end. Two screws must go through each 4-inch-wide board into the corresponding skinny end of the 8-inch-wide board. The finished product will have four square sides with an even top. The rafter-side boards will ride on top of the rafters while holding the side boards in place above the ceiling.

Place the custom-made attic access box in the attic-access hole with the rafter-side boards of the sleeve resting on the rafters. Screw the rafter-side boards, at an angle, into the rafters in the middle of each. Run a screw through the ceiling's drywall in between the rafter's board.

Nail the access door trim into place with 4d finishing nails. Prefabricated doors have the trim pre-cut and ready to install. Custom doors require a custom-fit opening.

Measure the exact width of a piece of door trim. Add twice this amount to the length the drywall hole's four sides. Subtract one inch from each side measurement. Use a circular saw to cut a piece of trim at each side's final measurement, four cuts total.

Lay out the 45-degree cuts on each end of the trim pieces with a carpenter's square and pencil. The long end of the trim will correspond to the outside of the trim package, and the inside of the trim should rest to the inside of the drywall opening. Visually check each cut to make sure the contour matches between each piece. For example, the thick part of the trim should finish on the outside of the frame on all four sides with cuts angling in to the thin side.

Cut the angled sections off the ends of the piece of door trim with a circular saw.

Tack one rafter-side trim piece to a rafter using a 4d finishing nail in the center of the trim board. The inside edge of the trim should extend a half inch into the ceiling's hole, and the inside cuts should start a half inch in from the sides of the holes, centered in the opening. Tack the remaining sides into place using the same method. Adjust the four pieces to fit each other and nail the corners into place two inches from the end. The finished product will extend into the attic access hole by a half inch on all four sides.

Apply weatherstripping around the top of the access door's frame.

Place the saved insulation onto the top of the attic door.

Lock the door into place. Prefabricated doors use manufacturer-supplied mounting hardware, usually L-brackets or some type of retaining clip. Custom doors use the cutout section of ceiling as the door. Angle the door into the opening, turn the board until the sides line up correctly and set the door in place on the weatherstripping.