Plumb the corners with a level and brace them with 2x4s.
Framing out attic.
Place 1 piece of timber along the edge of the hole and using the nails fix it into position.
Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches.
Note that only one stringer is needed in figure 17 because the ceiling joist provides one side of the frame.
Have a pro check the structure.
Stand the front wall and align it with the marks on the floor.
Framing the opening can be easy if you can locate the ladder so that it is parallel with the existing ceiling joists.
If the ceiling joist does not provide one side of the frame cut a second stringer the same length as the first one.
Nail the lumber to the edge going across the length of the timber so that the wood is held securely in place.
Use screws to attach sheets of birch plywood to the angled ceiling over the insulation making sure to drive the screws into the ceiling joists.
If the roof structure consists of trusses rather than rafters particular attention should be paid to.
Most attic ladders are made to fit between joists set at 24 inches on center.
Place the next piece of lumber parallel to the first and nail it into position in the same way.
So let s break this down.
Cut a stringer to this length.
Hire an engineer to inspect your house s foundation and framing to ensure they can carry the extra load.
Shim under the bottom plate to level it if necessary then nail it into the floor joists with 16d nails.
If you want your attic space to have a flat ceiling you ll need to add collar ties to the framing.
A finished attic weighs a lot more than boxes of off season duds.
If the framing in the attic shows evidence of physical damage further evaluation is needed.
Our ceiling joists are 2 x 6 s.
Install the lower header with joist hangers figure a and assemble the front wall on the attic floor.
Run the plywood down to the top of the knee wall.
They are usually twice the size of the surrounding framing materials.
At a minimum you may need to strengthen the attic s floor joists which are often too shallow or spaced too far apart for the job.
The plywood will create a smooth strong ceiling without having to apply drywall tape and mud to the ceiling.
