Ridge Board....What's That?

[Joe Funderburk, CMI]

Originally Posted by dvalley

I always recommend collar ties on those older roof systems that have no ridge board.

With a roof this old, if the exterior roof field is not showing any signs of sagging, adding collar ties is simply ...a precaution. Collar ties won't do much today. Especially if the roof field appears to be level throughout.

David, don't ceiling joists running parrallel to, and fastened to, the rafters effectively serve as collar ties? Collar ties are designed to prevent the spread of the rafters, and the joists serve that purpose if properly tied in. The collar tie is supposed to be in the bottom 1/3 of the rafter, and that's exactly where the joist is. That's my understanding of it.

If I did't see any signs of sagging, separation, etc., I think I'd just recommend monitoring due to the lack of a ridge board, which is designed only to provide restraint. I'd hesitate to recommend modifications to a roof system where I didn't see any problem.

[Robert J. OConnor]

Rafter Ties are different from Collar Ties (see my previous post).

If there are no collar ties or ridge board to toe nail rafters into, it is considered good practice to install gusset plates or top straps at the rafter butt connection (required in high wind areas).

JMO & 2-nickels ...

[David P. Valley]

Originally Posted by jfunderburk

David, don't ceiling joists running parrallel to, and fastened to, the rafters effectively serve as collar ties? Collar ties are designed to prevent the spread of the rafters, and the joists serve that purpose if properly tied in. The collar tie is supposed to be in the bottom 1/3 of the rafter, and that's exactly where the joist is. That's my understanding of it.

Collar ties are usually placed in the upper third of the roof. Collar ties are not meant to prevent the horizontal spreading of the rafters or act like rafter ties.


They are intended to prevent uplift from wind and really nothing more.
Rafter ties, which can be ceiling joists are placed near the bottom of the rafter and help to prevent the horizontal spreading of the rafters .

[Peter C. Russell]

I have always gone by the rule of thumb that the collar tie needs to be 1/3 the legnth of the rafter and that is short point to short point.

IE. if you have a 24 foot rafter on a 12 pitch the collar tie should be 8ft from the short point of the 45 degree angle.

[dhelm]

Originally Posted by roconnor

Rafter Ties are different from Collar Ties (see my previous post).

If there are no collar ties or ridge board to toe nail rafters into, it is considered good practice to install gusset plates or top straps at the rafter butt connection (required in high wind areas).

JMO & 2-nickels ...

I agree completely with both posts. And...the primary purpose of a ridge board (not to be confused with a structural ridge) is to provide something to nail the top of the rafter to. It has no structural significance.

[Kenton H. Shepard, CMI]

Well... the ridge does support the top edges of the roof sheathing at the peak, between rafters. More important now that we use plywood instead of boards for sheathing. It also provides something solid to nail the top of the barge rafter or fascia to at the rake (gable).