Nail the 2 by 4s to the top of each ceiling joist with 2 16d nails.
Framing an attic ceiling.
If you have attic trusses not conventional trusses the members will be sized to support living space.
The plywood will create a smooth strong ceiling without having to apply drywall tape and mud to the ceiling.
Ensure ends of insulation are butted together and flush to underside of framing.
Space these boards 4 ft.
Install and paint the ceiling 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.
Apart and attach the ends to the ends of the rafters.
Collar ties are horizontal members that like rafter ties extend from rafter to rafter but.
Attic floor framing attic floors are made with floor joists or with truss members.
Ensure insulation extends to the outside edge of the exterior top plates and to the peak of the cathedral ceiling.
If you have a rafter framed attic the floor joists may or may not be large enough for living space and may need to be reinforced or replaced.
Most houses attics are built without flooring and are not designed to carry the heavy load of finished space.
However in some cases the joists are intentionally built strong enough for the homeowner to later build out the attic.
Friction fit insulation between and parallel to the attic framing members.