Ridge beam or ridge board

[Jeff Remas]

Saw a 3/12 pitch roof today with a ridge board instead of a beam. I think it should be a beam, not a board for that little of a slope. Asphalt shingles over ice and water shield from top to bottom. Very cold today not above 10F.

[Gunnar Alquist]

I don't know if the slope really matters. The issue would be span. Any sagging in the roof system?

[Jerry Peck]

Saw a 3/12 pitch roof today with a ridge board instead of a beam.


Jeff,

A 3/12 slope is the lowest acceptable in the code for a ridge board.

If no sagging, and the rafters line up opposite each other, should work.

From the 2006 IRC. (underlining is mine)

- R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.

[Jeff Remas]

I found a new way to ask questions where we all learn something without being accused of being a dick.

The WFCM coincides with the IRC on this one. Not all codes do however.

[Jerry Peck]

I found a new way to ask questions where we all learn something without being accused of being a dick.

Doesn't change the fact, though. :p ;) :D

[Evan Grugett]

Jeff,
As usual JP is right on. Many older houses in this area have ridge boards, mostly T&G 1/2" x 6" (sheathing boards), regardless of the roof pitch (pre-date the modern codes). Some real old ones have no ridge boards at all, remember that wood shingles on nailers common then are a a pretty light roof covering.
If there are no sags in the roof it should work.

[Damon Sagehorn]

Hello,

The key to the performance of the system over time is if the ends of the rafters are properly tied together creating the necessary triangle. ie. tie the rafter ends to the ceiling joists and if the ceiling joists are multi-piece tie the pieces together at the overlaps.

Damon