George wrote:
On Fri, 12 Jan 2007 21:37:06 -0600, "mayojcm2003"
wrote:

I am going to roof my house soon and would like to know why some valleys
are cut valleys and some are woven. I live in Texas and most every house I
see has woven valleys. I lived in another state and most were cut valleys.
Is there a specific reason for this?

Personal experience (not a roofer, but my family does its own roofs):

We always did 'open' valleys, where about 1' of rolled roofing was
exposed in the valley. Underneath, we put sheet metal over the felt,
then 18" rolled roofing (face down), then 36" 90# roofing face up, then
shingles up to a cut line.

I did my roof that way about 15 years ago. The valleys all failed in
10-12 years, long before the shingles. It was a PITA to re-do them
(woven now, for sure). Asking around, the story I got was that this was
a general problem - that rolled roofing does not hold up to sun as well
as shingles, and that woven was the recommended way to go. Looking at
other roofs around here, I see the same thing - (open) valleys failed,
shingles OK.

These are all relatively steep (40+ deg) roofs, in Syracuse NY.

George

I never heard of doing it that way and can't see any benefit to it.
Also I wouldn't call it an 'open' valley. It also sounds like PITA to
lay it originally.

Harry K