Roof Framing
There are two accepted building methods for roof frames — the truss frame and the convential frame.
Truss Frames
Truss frames (also called web frames) are built at the factory and are shipped to the job site in large pieces. Once at the job site they are assembled by framing carpenters. Truss frames are easily identifiable by the way they look.
Characteristics of Truss Frames
Truss frames are webbed together.
The lumber may be 2" by 4" including the rafters.
Truss frames are joined with metal ties.
The roof system distributes weight to the ceiling joist.
The webs of lumber may resemble a "W".
Truss Roof System
A truss roof system should never be altered nor should truss roof systems be converted to living or storage space. Load are pre-calculated to handle the weight of the roof system, ice and snow. Additional weight could cause the roof system to collapse.
Conventional Frames
Conventional roof frames (also called stick built roof frames) are constructed on the job site during the house framing phase of construction.
Characteristics of Conventional Frames
2" by 6" or larger pieces of lumber are used to form the rafters and ceiling joist.
Collar ties a few feet below the ridge beam.
A general open space.
Conventional Roof Frames
Conventional roof frames can shift the weight of the roof system to the perimeter walls and other load bearing interior walls. Load bearing capacities are determined by the size and spans of the lumber used to frame the roof system and the floor system. Conventional roof systems can be modified to accommodate living space, skylights, dormers and other structural changes with relatively little modification.
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