I have an old house with low roof. I think the pitch is like 4/12. The house is only 25 feet wide, 60 feet long, and it has gable ends. The shingles are in condition but the roof is sagging in some places. It also just feels real weak and bouncy when you walk around on it. The existing framing consists of 2 by 6 rafters going up to the spine and that’s it. The fact that there are not any supports coming down from the spine to the ceiling joists concerns me. It’s like trusses without any webbing. I talked to one carpenter about this and he said that he has seen these low pitch roofs actually push the exterior walls out before. He said he went back through and added ties from the rafters to the ceiling joists.
Should I do something like this? What if I ever add architectural shingles (heavier) or a metal roof?
Replies
I doubt adding boards in the attic would do much of anything.
First, you'd have to jack the roof back into a straight position. Then you'd have to try to nail braces in there. The forces involved would probably take so many nails that it would be impossible to get enough in the braces to do any good. And it would sure be a lot of work.
I've had guys in similar spots ask me to design some roof trusses to correct such a problem. We designed some scissor trusses with sloped bottom chords to clear the existing roofs. (So the existing roof could remain) But once they found out how expensive it was, every one of them quickly dropped the idea.
Either this man is dead or my watch has stopped.
I have done this lots and it is a quick and easy fix. Get a real carpenter to add some purlins and roof bracing from rafters down to interior walls, not to the joists.
KK
kkearney-
Thanks for the reply. I'm not familier with purlins. Can you describe them to me?
ARRookie,
Purlins are like the short web on a truss. They run from an interior wall up to 2X strongback on the bottom of the rafters at more than a 45º angle. Usually braced to every other rafter. Just typical framing that acts to decrease span.
KK