How to Lock Your Attic's Entrance

Find an installation spot that is free of obstacles, such as air ducts, electrical wires, plumbing or other items. Wear protective clothing, glasses and a face mask when working around insulation. Check by measuring to be certain the door and ladder will have enough room to swing down properly. Measure to make sure the ladder legs will land on flat floor. If ceiling joists are running across the opening, consult an architect for framing instructions. Do not cut the joist without professional advice.

Clear the area and place a drop cloth on the floor. Draw the opening size on the ceiling (the opening size is noted on your product instruction sheet). Cut the drywall ceiling with a drywall saw following the line. One edge of the opening should be against and parallel with a ceiling joist. Place the ceiling and excess insulation in a garbage bag. Shove loose insulation away from the opening so it won't fall.

Follow an architect's instructions if you need to cut ceiling joists. Some attic ladder manufacturers' instructions advise on common ceiling joist configurations you can use for some modification installations. Most kits are designed to fit within or between ceiling joists, so cutting often isn't required.

Measure along the ceiling joist for the location of your headers. A header is a block of wood of the same dimension of lumber as the ceiling joist that is nailed through the sides of the ceiling joist at either end of the attic ladder opening. Your kit will include the distance between the headers. A header should fit tightly between two joists and may need to be hammered into position. The header should be at a 90 degree angle to the joist. Nail three nails evenly spaced into each end of the header through the joist on each side.

Cut two pieces of 1-by-4-inch board wider than the opening. Nail these temporary supports into the headers using double-head nails (so you can remove them more easily). The inside edge of the 1-by-4 should overhang to the inside of the opening by 1/4 inch evenly. Repeat for the second header. These boards will support the frame of the attic ladder during the rest of the installation.

Place a piece of scrap plywood in the attic for the person who will be in the attic during the installation. Remove the attic door handle and leave it for the person staying under the installation inside the house. The attic person should climb a stepladder into the attic and guide the attic ladder assembly through the hole. He then should center the assembly on the temporary support boards. Once in the attic, the person will be there for the rest of the installation.

Shim the attic ladder between the frame of the ladder assembly and the headers to lock the ladder so it cannot fall through the opening during installation. The person below should open the attic ladder by inserting the control rod into the hole and turning the rod 90 degrees counterclockwise. Pull the lid fully open but do not unfold the ladder (it is not installed and will collapse).

Divide the length of the opening by four. Measure and mark the opening (three marks) on each long side. Install shims from above and below at the marks. The shims should not extend below or above the attic ladder frame. Measure across the diagonal on the frame. When the frame is straight, both diagonal measurements will be the same. Drill 1/8-inch holes through the frame and shims and into but not through the joists.

Nail through the frame, shims and into the joists using 20d nails or wood screws. Do not hit the hinge or mechanisms. Trim any shims sticking out. Remove the temporary shims at the headers. Unfold the ladder and turn the bottom section under. Support the bottom section so it is level with the floor. Loosen the screws in the brackets that hold the ladder to the lid. Move the ladder away from the lid 1/2 inch or more and tighten the screws. The ladder should be parallel with the lid.

Measure the front of one ladder leg (from where the leg is folded under) from the end of the non-folded leg to the floor. Note the measurement. Measure the back of the same ladder leg to the floor. The front measurement will be longer than the back measurement. Transfer these measurements to the bottom ladder section and draw a cut line between your marks. Make sure the front of your bent ladder leg is at the front of the ladder when you extend it forward.

Cut the legs 1/2 inch too long. Check the ladder by unfolding it correctly. The ladder should be straight with no bent sections or gaps at the metal hinges. Make the final trim cut to fit your exact conditions. The bottom of the ladder should rest solidly on the floor, and the ladder should be straight with no gaps at the hinges. Sand the bottom of the ladder to remove any splinters or rough spots.

Pull the insulation back up against the frame of the ladder. The ladder should be safe and ready to use.