Alternatives to Roof Rafters

Trusses

• Trusses are one of the more popular rafter alternatives you may find in a home because the beams are positioned to support a roof load in a more effective and economical manner, according to a document provided by website My Discount Tools. A truss is made up of at least one triangular unit made by joining straight beams of wood. The points where the beams join bear the majority of the weight and impact of tensile forces. My Discount Tools states that the number of subdivisions in trusses depends on the type of home construction and the length of the area the trusses will support. Truss types seen in homes include the Pratt truss, attic frame, dual pitch, fink, gambrel and tray ceiling trusses.

Purlin

• Purlins are horizontal supports in the roof of a home, which help support the sheathing or roof deck. Instead of using roof rafters that are spaced close together, contractors may use purlins to help support trusses or to support corrugated sheet metal used in roof construction, according to My Discount Tools. When used in small roofs, purlins are inserted between and nailed through trusses. In larger homes that use heavy trusses, My Discount Tools states that the purlin may rest on trusses to help support the sheathing.

Joist

• In a home, joists are horizontal supports that run either beam to beam, wall to wall, or wall to beam to support a roof or ceiling. A series of beams generally support the joists, which are arranged in a parallel manner. Many roof rafter alternatives are made of wood, but joists are also made of concrete or steel. In home construction, particularly in cabin designs, exposed floor joists in the ceiling may be made of square timber, rounded timber or contoured logs.

Joist Considerations

• If you choose to install joists, A1 Wood Flooring suggests using boards that are the same width. Avoid using lumber that has large knots because such a defect could compromise the integrity of a joist. Additionally, moisture could impact the sound and look of a joist. If you use wood that contains a lot of natural moisture, the wood will shrink over time as it begins to dry.