If you want your attic space to have a flat ceiling you ll need to add collar ties to the framing.
Framing out attic.
Install the lower header with joist hangers figure a and assemble the front wall on the attic floor.
Framing the opening can be easy if you can locate the ladder so that it is parallel with the existing ceiling joists.
Have a pro check the structure.
Shim under the bottom plate to level it if necessary then nail it into the floor joists with 16d nails.
If the roof structure consists of trusses rather than rafters particular attention should be paid to.
Note that only one stringer is needed in figure 17 because the ceiling joist provides one side of the frame.
Hire an engineer to inspect your house s foundation and framing to ensure they can carry the extra load.
If the ceiling joist does not provide one side of the frame cut a second stringer the same length as the first one.
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.
Run the plywood down to the top of the knee wall.
Most attic ladders are made to fit between joists set at 24 inches on center.
We enlarged the entry to the kitchen and made a header to frame out a doorway here.
A finished attic weighs a lot more than boxes of off season duds.
Place 1 piece of timber along the edge of the hole and using the nails fix it into position.
Stand the front wall and align it with the marks on the floor.
Plumb the corners with a level and brace them with 2x4s.
Nail the lumber to the edge going across the length of the timber so that the wood is held securely in place.
The plywood will create a smooth strong ceiling without having to apply drywall tape and mud to the ceiling.
Place the next piece of lumber parallel to the first and nail it into position in the same way.
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.
I needed to cut one of those 2 x 6 s out to make our attic access larger.
They are usually twice the size of the surrounding framing materials.
Collar ties are horizontal members that like rafter ties extend from rafter to rafter but.
So let s break this down.
Our ceiling joists are 2 x 6 s.