[texasgeezer]

Recently was reading Owens Corning installation instructions. They don't seem to require woven valleys to have ice & water, metal, or other extra waterproofing membrane for woven valleys. They seem to be ok with just extending the underlayment across the valley from each direction. Is that correct?

Also couldn't find any comments on how the underlayment should be applied as far as being laid flat without wrinkles. One house, two houses away, had the asphalt shingles replaced the previous two days. The Owens Corning underlayment was horrendous in how it was laid down. Plus no valley flashing. Will try to post pictures if I figure out how to do that.

 

[texasgeezer]

I've kept reading about valley flashing. So far, I think I've found that some shingle manufacturers ask for a "better material" than standard underlayment. Others seem not to have that requirement.

On the pictures with the Owens Corning underlayment. I can't get any yes or no from Owens Corning. One guy says they warrant their material not how it's installed. Another says only metal is considered flashing. Same guy said the installer must use common sense. To me, that varies by individual. They won't comment if the pictures don't follow their installation instructions for PROARMOUR underlayment. From my reading the installation instructions mention nothing about it being required to be laid smooth without wrinkles. Frustrating not to get an opinion. from the manufacturer on ' if their instructions were followed'.

Please comment if you have an opinion or knowledge.

Thanks

 

[Deerfly]

I'd think the wrinkles in the underlayment are acceptable. There are manufacturers out there that have pictures of their underlayments installed on advertising that look similar.
I like to install it flat and smooth, only stapling the laps, never leaving it exposed longer than overnight, with minimal rain chance. All this in hopes that it sheds water as easily and fast as possible, with minimal penetrations, weather covered by shingles and acting as a secondary line of protection as designed or drying in a re-roof or new construction.

 

[texasgeezer]

I have to disagree, wrinkles can collect water that increases the chance for it to enter places where it should not be. Also wrinkles could reduce resistance to wind if shingles are blown off. Also wrinkles could telegraph through the shingle and create an appearance issue. Plus is the shingle does not lay flat it would be more susceptible to wind damage.

I found this wording on one of GAF's underlayment installation steps:

STEP 3: Lay Out FeltBuster® High-Traction Synthetic Roofing Felt.
a) Apply FeltBuster® High-Traction Synthetic Roofing Felt parallel to the eaves.
b) Install without wrinkles. Lay flat, cap nail flat. Do NOT STRETCH during installation.

Also to me, underlayment that is installed with excessive ' wrinkles ' indicate a desire to maximize profit over workmanship. This maximizing of profits would probably impact other areas of the roof job such as proper nailing and water proofing around penetrations

 

[texasgeezer]

Nice looking installation and the bundles aren't stacked on the peak. Didn't see any vents, is it a garage type with no attic? Want to travel to North Texas?