Hip Roof Ridge Beam
Supporting hip truss roof load and under hip master concentrated load.
Hip roof ridge beam. Determining the ridge beam height. The ridge beam shown below at the living room of a 1950s modern style ranch house in gainesville has cracked at mid span and is slowly heading towards failure after. Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam. A ridge board is a non structural member that serves as a prop for opposing rafters to rest against and connect to.
A structural ridge beam is a horizontal beam placed at the peak or ridge of a roof and is designed to carry much of the live and dead loads or weight of the roof structure by itself. Because a ridge beam often carries a significant area of roof load they can exhibit structural distress due to a defect in wood impact on the roof or use of an undersize beam. The hrc may be sloped downward a maximum of 45. The first step in the process of erecting the hip roof is to get the ridge beam into place at the top of the roof.
The loads on the ridge beam are carried by vertical posts at the beam ends down through the building structural walls to the building foundation. More accuracy could be achieved by taking each truss as an individual pt load. Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3. This is the typical structure of a hip roof.
As you can see the ridge board or ridge beam is holding up the jack rafters at the top of the incline. The ridge board holds them in place. Hip ridge the header 4 0 load h hip jacks load b load i approximate load conditions based on a truss use of partial uniform loads. Hrc is a field slopeable connector that attaches hip roof beams to the end of a ridge beam.
Place the 4 6 common rafters in their designated positions along the 2 longest walls and nail them firmly to the wall with a nail gun. The finished ridge beam height z above the top of the wall will be m plus the y height. If you know the slope x in 12 you want to use for your roof framing design you can use it along with the run r to determine the height of the ridge beam for example if the slope is 4 in 12 and the run is 12 feet the ridge beam height m will be 4 feet.