How Much Temporary Bracing Is Needed For Hip Roofs

Without bracing walls or decks can collapse since there isn t any lateral stability.

How much temporary bracing is needed for hip roofs. Some claim true rectangular or square hip roof structures are self supporting. Measure the distance between the angled hip rafter and the top of the wall at 20 in 51 cm increments and cut jack rafters to fit. Measure the height of the rafters from the point where they meet the floor joist to the peak of the roof. In narrow fronted roofs and mono pitched roofs where the braces cross the intersection detail below should be used.

There should be a minimum of four diagonal rafter braces in each roof. It is best to brace the inside of the trusses before handling them. 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. Wood truss restraint and bracing guide overall truss length 1 maximum spacing up to 30 10 on center 30 45 8 on center 45 60 6 on center 60 80 2 4 on center 1.

A ceiling diaphragm may be used as an alternative. 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 overall truss length refers to the overall length of the truss including cantilevers exclusive of overhangs. The help of a second or third person is necessary even to lift a truss onto a single story roof.

However for an assembly of roof trusses buckling might occur in the same direction for every truss. For example using the 2 percent rule bracing force for a web member that must resist 4 000 pounds compression is only 80 pounds. If hips are self supporting why are braces required. Use 1 by 4 inch boards called purlins as temporary braces for rafter trusses.

Be sure to check your building codes for diagonal brace requirements. 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. Divide that number by four to determine how many braces you need to place on the rafters. Nail these temporarily to the outside edges of the rafter sides starting with the third truss.

Bracing force for an individual roof truss tends to be quite small. Nail braces vertically every 4 feet along the top and bottom of a gable truss. Install 2x4s at a 45 degree angle.