Installing an attic ladder can be intimidating. From where to locate the door (where to cut the hole), to manhandling the door unit, it’s not a relaxing job. People think this has to be a two person job, but it isn’t so long as you are smart about it.
The key to making it a one-person job is to use a ledger board to support the door unit. You can cut the hole and push the unit into the attic through the hole. The tricky part is installing the door securely and then being able to climb out of the attic. You will typically cut a hole 54″x 22.5″. You will frame a box at the short ends with the same dimensional lumber that is at the joists. At the short sides of the rectangle you will screw a ledger board (use a 1″ x 4″) so that only about 3/4″ inch of it extends into the opening. You will do this from below to create a lip that the unit rests upon as it is installed. If you extend more of the boards into the opening, then the door won’t be able to open from above and you will make this a two-person job because someone will have to remove the ledger boards from below.
Once you have the ledger boards in place, set the attic ladder unit onto them. These will be the only things supporting the ladder until you secure it into the framing. There are recommended locations on the ladder to drive nails or screws into the ladder and the surrounding framing. Once it is secured, you should be able to push the ladder open and climb down.