Gable Roof Without Ridge Board

In this design the tops of the rafters attach to a load bearing ridge beam that runs along the length of the roof.

Gable roof without ridge board.

The picture above shows the plan view of a gable roof ladder trusses are made up using four noggins bridging at each corner to support a rafter outside the building. In conventional gable roof framing the slope of the roof is formed by rafters that run diagonally downward from the peak of the roof to the tops of the exterior walls of the building. Its only job is to provide a connection point for the roof joists on each side of the roof. Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam.

It s often just a nice way to bring the rafters together. Because the ridge board is a smaller member typically only an inch thick sometimes even less it is not a structural member and doesn t carry the gravity load. A ridge board is a non structural member that serves as a prop for opposing rafters to rest against and connect to. Putting it together is relatively straight forward if you have basic carpentry skills and use precise measurements.

Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3. A structural ridge is the standard alternative to ceiling joists. That rafter outside forms the overhang for the barge boards to fix to and so the soffit boards and ventilation are continuous all the way. You don t need a ridge beam but you do need a way to keep the walls from spreading.

A gable roof is a simple symmetrical triangular roof. A ridge board isn t a beam per se. The typical gable roof diagram above shows the r length measured from the outside wall to the middle of the ridge beam the rafter section diagram below typical of a shed or patio cover roof shows the r length measured from the outside wall to the outside face of the ridge beam either one is acceptable depending on which type of roof you are building but if you are using the. For 2 x 4 rafters use a 2 x 6 ridge board.

Choose a ridge board that is one size larger than your common rafters. The ridge board s length will be the outside measurement of the building plus the length of the overhang at both ends. For 2 x 6 rafters use a 2 x 8 ridge board and so on. Ridge board the engineering principles of the ridge board are a bit more complicated.