Roof Joists Separating

If you are framing a cathedral ceiling there are a couple ways to deal with the need for rafter ties.

Roof joists separating.

With some structures floor joists are required to be 12 or 24 inches apart on center. Basic ceiling joist spacing the standard construction of interior framing in a home uses 16 inch on center oc spacing for ceiling joists. Given that 2x8s are actually 1 inches wide it works out to be 14 inches between each joist. Truss clips prevent cracks builders can prevent truss uplift during the framing phase of house construction by refraining from nailing the trusses to the wall plates.

Our range of timber joist floor solutions include cavity insulation high performance gyproc plasterboards and gypframe sound insulating bars. Timber joists are widely used within internal floor and separating floor construction both in residential and commercial applications. As the accumulated weight of the roof creates pressure the hangers pull loose from the beam and the exterior walls to move. But larger is not always better when builders are constructing a home or adding a room addition.

Our solutions maximise acoustic and fire performance to both meet and significantly exceed the requirements of building regulations for new build and refurbishment projects. Normally floor joists are spaced 16 inches apart on center. If the trusses are nailed to the wall plates the resulting distention at the points where the upper and lower chords meet can separate the ceiling from the walls. Rafter ties or ceiling joists acting as rafter ties are required by code unless the house is designed so that the walls or a structural ridge beam carries the full load of the roof.

Joist spacing in this design mode incorporates different types of wood used in ceiling construction including 2 grades of southern pine douglas fir and hemlock fir types which are the most common. The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example. This means from the center of one upright joist to the center of the next. Roof sheathing deck or slab of a fire resistance rated floor or roof above the ceiling of the corridor shall be permitted to be protected by the use of ceiling materials as required for a 1 hour fire resistance rated floor or roof system.

Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor.