Post And Beam Roof Rafters

The main elements of the gable roof layout are the ridge beam common rafters and wall plate.

Post and beam roof rafters.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. If one side of the roof is supported by the house and the other side is supported by the beam divide the total load by two as the beam is only supporting half of the roof. The first roof area is constructed with heavy timbered components that are secured to the ridge beam and second floor beams. An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry.

These timbers are then tied together with collar ties the horizontal members and gusset plates the metal fasteners as you can see in the photo below right. Exposed ridge beam collar ties or purlins for cathedral areas as required and 6x8 douglas fir plate beams typically 2x12 spruce rafters 2 o c. If there is also a beam in the middle of the roof divide the total load by three. And cdx fir plywood.

First roof area assembly. Above these components is a rack of common rafters. Roof slope is commonly represented as x in 12. Set the laser level on a raised level platform like a portable saw station and shoot and mark the red dot on each post keeping the laser level perfectly level as you turn your aim from post to post.

Post and beam framing is more simple and actually an older style with main carrying members bents or lintels supporting joists and rafters that are notched in to the beams. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Use a laser level to mark each post. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

There is a hierarchy of timber framing at work here with trusses supporting the ridge and purlin beams. If our example roof has only one beam it must carry half of the total load or 4 000 pounds. For areas with attic space above flat ceiling ceiling joists are included but the remainder of the ceiling system above is by owner contractor. If your span table shows the roof beam cannot support the roof rafters for the whole length of your house you will want to choose a built up roof beam whose maximum spans are the same as or slightly longer than your chosen floor beam spans.

For example a roof slope that rises 6 inches for every 12 inches of run is said to. These roof types have the basic elements of all of the other roofs and make it a perfect place to begin the discussion. Post and beam home design. In the same way you may need posts to support your roof beam.