A ridge board connects the upper ends of the rafters forming the apex of the triangle. Typically, a ceiling joist spanning from opposite exterior walls connects the lower ends of the rafters together, forming the base and completing the triangle. See example roof cross section shown below.
How do you support a ridge board?
- Hand up the first gable-end rafter.
- Hand up the opposing gable-end rafter and toenail into place.
- Repeat with a second set of rafters, squaring this set with the ceiling joists.
- Move about halfway down the roof and repeat with a third set of rafters, to provide support for the middle of the ridge board.
What size board is used for roof rafters?
Most Common Thickness. For rafters spaced 20 or more inches apart, 1/2- or 5/8-inch plywood is recommended. The most common rafter spacing is 24 inches, and 5/8-inch plywood is recommended for that. It will support roof loads for most situations and is the standard for most roof applications.
Do I need a ridge beam or a ridge board?
Conclusion. A ridge beam is a necessary structural member that carries half the roof load and must be used when building roofs with slopes less than 3/12. A ridge board isn’t structural and is an aid in the placement and spacing of rafters.
Is a ridge board necessary?
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. The ridge board is installed to provide a bearing point where the rafters meet, and it also helps with alignment along the ridge.
Do ridge boards need support?
The only purpose of a ridge board is to provide a stable bearing surface for the tops of paired rafters to meet. This can be provided by horizontal ceiling rafters that connect between the walls or a concrete block wall with a tie beam. So a ridge board does not have to be supported.
How far can a 2×6 Rafter span without support?
2-grade 2×6 joists can span up to 10 feet 9 inches from beam to beam when spaced the standard 16 inches apart with a maximum live load of 30 inches per square foot.
How thick should a ridge board be?
1 inch
Ridge boards shall be at least 1 inch nominal thickness and not less in depth than the cut end of the rafter (IRC section R802. 3).
