Roof Ridge Beam Detail

Ridge beam height above top of slab height of wall z.

Roof ridge beam detail.

The formula for determining the finished height of the ridge beam from the top of the slab to the top of the ridge beam is. The sloped roof joists span between two pinned points. The difference between them is that a ridge beam is a structural member that bears half of the live and dead loads of the rafters on either side of it but a ridge board is not structural. 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.

Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3. An explanation and real world example of a structural ridge beam used to support roof rafters. With this design the ridge beam bears much more load weight than the ridge board on a standard stick framed roof. Yes either a ridge board or a ridge beam is necessary and required by the building code where roof rafters meet at the the center of their span.

So if your house is 26 feet wide and the roof ridge beam is centered on the house you will need a rafter that can span 13 feet. Let s use this example and find a size of rafter that will work. The ridge beam could also be flush with the joists the ridge beam is typically a larger member like a 4 x 12 and carries the gravity load of the roof joists just as the bearing wall or header does at the envelope. One at the envelope of the structure on top of a framed wall or a header the other at the peak of the structure on top of the ridge beam.

Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley. The maximum spans in the table above are for the horizontal distance the rafter can span not the diagonal distance or actual length of the rafter. 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. See how a structural ridge was used to tie together a 1700s ti.

A timber frame roof has rafters and a ridge beam as with stick framing but the ridge is a large structural beam that the rafters sit on top of or sometimes fit into notches cut into the beam. Once the ridge beam has been positioned in place and supported by roof framing members you can determine the placement of a rafter by measuring down from the top of the beam y height and making a mark on the beam.