Roof
Roof assemblies can be categorized into four types: Lumber (Lumber Roof Systems), I-Joist (I-Joist Roof Systems), Pitch Chord (Pitch Chord Truss Roof Systems), and SIP (Roof Assembly Structural Insulated Products).
Lumber Roof System
Lumber roof systems are composed of rafters, sheathing, and a ridge board or ridge beam.
Rafter
Roof Assembly Rafter Products - An angled series of structural wood members designed to support roof loads. Typically, rafters are placed in plane directly opposite each other and connected at the roof ridge. They are notched at the lower end to fit and provide connection to the exterior wall top plate. Rafters are secured to the wall plate by toe-nailing or use of special metal plate fasteners.
Ridge Board
Roof Assembly Ridge Board Products - A non-structural wood member used at the ridge of a roof to provide a common nailing surface and point of bearing for opposing roof rafters.
Ridge Beam
Roof Assembly Ridge Beam Products - A structural wood member used at the ridge of a roof to support the ends of roof rafters and transfer roof loads to supports.
Sheathing
Roof Assembly Sheathing Products - The structural covering placed directly over framing members which also serves to transfer loads into the rafters. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets, although longer lengths are available.
I-Joist Roof System
An I-Joist Roof System is composed of an i-joist, ridge beam, and sheathing.
I-Joist
Roof Assembly I-Joist Products - A structural member manufactured using sawn or structural composite lumber for flanges and structural panels for webs, bonded together with exterior exposure adhesives, and forming the cross-sectional shape of an “I”. I-joists used in roof construction are supported by exterior walls and a ridge beam.
Ridge Beam
Roof Assembly Ridge Beam Products - A structural wood member used at the ridge of a roof to support the ends of I-joists and transfer roof loads to supports.
Sheathing
Roof Assembly Sheathing Products - The structural covering placed directly over framing members which also serves to transfer loads into the rafters. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets, although longer lengths are available.
Pitch Chord Truss Roof System
A Pitch Chord Truss Roof System is composed of pitched chord trusses and sheathing.
Pitched Chord Truss
Roof Assembly Pitch Chord Truss Products - In a roof truss, the three sides (or perimeter elements) of the triangle are called “chords”. The “webs” are wood pieces connecting the top and bottom chords. Chords and webs are the “members” or elements of the truss.
Sheathing
Roof Assembly Sheathing Products - The structural covering placed directly over framing members which also serve to transfer loads into the pitched-chord truss. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets.
SIP
SIP systems use engineered roof components in place of traditional wood frame construction. SIP systems provide advantages like better insulation and greater durability to seismic activity and strong winds.
Structural Insulated Panels
Roof Product - An engineered wood product composed of laminated layers of Oriented Strand Board and Expanded Polystyrene insulation. Panels come in multiple sizes and are often custom manufactured with pre-made cut-outs for doors and windows.