Find the area in the home you want the attic access hole to be installed.
Find the studs, or rafters, on either side of the area where you wish to create the access hole. Drill a hole through the center of the ceiling, between the two studs.
Crawl into the ceiling through an existing access hole. Find the hole in the ceiling by finding the rough location of where you drilled the hole. You may need to pull up some insulation.
Mark out a 3-by-3-foot area. The access hole will run parallel to the joists.
Lay down pieces of plywood along the joists to give you a place to work. Peel back the insulation from the 3-by-3 area.
Add 3 inches to the 3-by-3 area and mark the joists with a pencil. Cut out the joist to the ceiling drywall using a reciprocating saw. Remove the piece of joist.
Measure the length for the headers. Cut the headers using the same plywood used for the joists. Set the headers in place and screw them into the joists. Add a new joist to close off the area to a 3-by-3 section. Screw the joist in place.
Cut through the drywall with a reciprocating saw using the joist framing as a guide.
Secure the cut drywall with drywall screws, attaching it to the joists above.