How To Size Roof Ridge Beam

For 2 x 4 rafters use a 2 x 6 ridge board.

How to size roof ridge beam.

Step 1 choose a ridge board that is one size larger than your common rafters. For 2 x 6 rafters use a 2 x 8 ridge board and so on. Multiply the load per square foot by the total area of the roof. Timber steel framing manual single span ridge beam.

Refer to sfpa s publication southern pine headers beams download in publications that includes all size selection and allowable load tables. Multiplied by 40 pounds per square foot equals 8 000 pounds. For each application a pdf download is available. Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3.

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. Rafter to ridge beam connection framing roof ceiling construction structural ridge beam absolute deflection in a ridge beam structural ridge beam tricks of the trade. 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. Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam.

No matter what the specs say. It has been my experience to never use a beam smaller than a two ply 2 x 8. Loading conditions are detailed below. This number represents the total load that your roof must carry.

The ridge board s length will be the outside measurement of the building plus the length of the overhang at both ends. Versa lam lvl size chart laminated beam span tables charts. If an example roof is 10 feet by 20 feet the total area is 200 square feet. Ridge beam height above top of slab height of wall z.