Thread: Purlin, no brace?

Have not seen this before. 20 year old house, rafter framed 16"o.c. with a perlin and no braces? Vertical piece (perlin) was only toe nailed to the bottom of each rafter. Roof was very solid to walk on and there was no noticeable sag in the rafters. I did not measure the span but est. at 15-16', probably within the acceptable span for 8" rafters 16" o.c. So why is the perlin there and should I call for P.E. ?

Originally Posted by Vern Heiler

Have not seen this before. 20 year old house, rafter framed 16"o.c. with a perlin and no braces? Vertical piece (perlin) was only toe nailed to the bottom of each rafter. Roof was very solid to walk on and there was no noticeable sag in the rafters. I did not measure the span but est. at 15-16', probably within the acceptable span for 8" rafters 16" o.c. So why is the perlin there and should I call for P.E. ?

If I assume S.P. #2 grade with a ground snow load of 30 psf, the allowable span (horizontal) is 16 feet, 2 inches for 2x8s at 16-inch o.c. I would assume that someone thought this may keep the rafters a bit more even. I see no reason to be concerned.

Originally Posted by Mark Reinmiller

If I assume S.P. #2 grade with a ground snow load of 30 psf, the allowable span (horizontal) is 16 feet, 2 inches for 2x8s at 16-inch o.c. I would assume that someone thought this may keep the rafters a bit more even. I see no reason to be concerned.

Twenty years and no sag adds to your argument. Thanks Mark.

It is probably intended to keep the rafters from rolling.

Originally Posted by Darrel Hood

It is probably intended to keep the rafters from rolling.

It could be, but that is not a good way to do that. Also, if attached properly at the top and bottom the rafters should not roll.