How Much Temporary Bracing Is Needed For Hip Roofs

If hips are self supporting why are braces required.

How much temporary bracing is needed for hip roofs.

Use a t brace to support the truss vertically. I recently acquired a calculation where such a point load was deemed to be 12 000 lbs on a 28 wide garage having a 10 12 pitch roof. A ceiling diaphragm may be used as an alternative. Depending on the size of the roof most hip roofs will have 4 6 short jack rafters that are spaced out every 20 inches 51 cm between the hip rafters and the king common rafters.

Bracing force for an individual roof truss tends to be quite small. It is best to brace the inside of the trusses before handling them. Diagonal braces are used to keep your building project square and structurally solid. There should be a minimum of four diagonal rafter braces in each roof.

In narrow fronted roofs and mono pitched roofs where the braces cross the intersection detail below should be used. A roof plane diagonal brace is required per 35 m 2 or part thereof of roof plane area for each roof plane plus a minimum of three hip or valley rafters per ridge plus ceiling plane braces at 2 5 m centres to the top plate supporting the jack rafters. Nail these temporarily to the outside edges of the rafter sides starting with the third truss. Nail braces vertically every 4 feet along the top and bottom of a gable truss.

Be sure to check your building codes for diagonal brace requirements. Install 2x4s at a 45 degree angle. For example using the 2 percent rule bracing force for a web member that must resist 4 000 pounds compression is only 80 pounds. Divide that number by four to determine how many braces you need to place on the rafters.

Measure the height of the rafters from the point where they meet the floor joist to the peak of the roof. Without bracing walls or decks can collapse since there isn t any lateral stability. Use 1 by 4 inch boards called purlins as temporary braces for rafter trusses. However for an assembly of roof trusses buckling might occur in the same direction for every truss.

Some claim true rectangular or square hip roof structures are self supporting. Brace other rafters as they are installed down the roof by nailing temporary 2 by 4 supports to rafter edges and to roof joists if rafters are being installed separately. The help of a second or third person is necessary even to lift a truss onto a single story roof.