Opinion on this 3-tab valley

Usually I’m used to seeing closed cut valleys but this one is unusual. Suggestions would be greatly appreciated.

Thanks in advance for your help

Woven valley. Common around here.



that’s one is typical of a poorly woven valley

it take foresight and layout to properly weave and have shingles line up

check this for further info

Hmmm…looking at the pic again, it seems to be architectural shigles rather than 3-tab. Could be an illusion too.

Greg’s pic are “laminated shingles”!

Yes, thanks.

BTW, good to see you back here.

Lapped roof valleys are always suseptible for leakage. Look and the picture, and imagine where the water drains. Water can flow down the right side, into the grooves/joints/slots of the other shingles. Suggest replace with metal drainage valleys.

eyes paid da gubment fer tha day off! :mrgreen:

always good to see the OWL

Woven is fine if the shingles are softened in the sun before positioning, and when woven so they cross near the center. Some of those cover 2-3 courses on the opposite side. I do them often, but that is poorly done.

Cut valleys should be a heads up…the roofer took the fastest, easiest, cheapest way to install the roof. Did he take any other shortcuts?

Woven valley’s such as this are typical…I do them myself however where he got off on is how he weaved them in…as you go up the valley the intersecting of the shingles are off…almost 12 inches away from the valley itself…this often happens when you have two different pitches and or the installer is not paying attention to detail.

Just curious, was there two different pitches going on?

I’ve done both Gary…woven valleys are just as good as metal valleys if not better. For an inspector to suggest an alternative method is exceeding SOP’s. This method is fine…its simply that the installer was not paying attention to the valley line.

The only way these types of valleys leak is from 1.) stepping in them 2.) perpendicular shingle did not extend far enough past the valley and 3.) the installer nailed to close to the valley.

Probably did not install the metal flashing underneath.
Just a guess.
T.Neyedli CHI§
BPCPA #47827


A well woven valley is hardly noticeable. You’re looking at it–then it dawns on you what you’re looking at. Both my son, and son-in-law, are roofers and use this technique a lot.


That is exactly why I say those who have actually worked in the construction business have an advantage in that they have seen various application methods and understand what works and what does not.

I have built homes in Ohio, Indiana, Va. and North Carolina…all using the same method… and have yet to ever had one leak… Go figure.

On the other hand when installing metal flashing one needs to remember that the metal does expand and contract hence the need for roofing cement on the edge (open valley)…guess what give away over time from the expanding and contraction…guess where the leaks come from.


PS. I am actually from Cincinnati… have built homes from Loveland to Mason, Delhi - Montgomery…nice place but I do not miss the cold.

Gregory- go to www.gaf.com there are videos to explain open, woven, and cut valley installations. Note woven valleys are recommended for 3 tab shingles not laminated.


Inspectors have to be careful not to define or limit what an acceptable application is without a proper basis and understanding that with many products applications can be limited to a specific manufacturers product and or series.

Owens Corning Installation Instructions state that woven valleysare acceptable for architectural shingles, however certain GAF’s architectural shingles are 1/3 thicker than many other shingles which is why they do not prefer the woven valley technique, yet depending on their other series their instructions show that woven is fine. In the previous link under section 10 it states woven or closed.

This thread is a prime example as to why inspectors have to be careful in what they state on their reports. Here we do not know the manufacturer (or series) yet we have some that are going to call it out and others such as myself that differ.

You call it out stating that this is not an acceptable method of installation, the roofer (or contractor) comes back and shows you the instructions show that woven is fine with that particular product then it make you look like you don’t know what your talking about…which now makes your client wonder what else you missed or overstated.

If you are concerned about an installation of a particular product then try to obtain as much information as possible about same before making a broad sweeping call. (this is also why I do not print reports at the site).
If you still are not sure then simply state that you are unsure about this method, recommend the client consult with a professional installer or better yet the manufacturer rep.

Let me also say about roofing application in general… the majority of roofs are installed incorrectly in some form or another…be it fasteners are not properly located or seated, caulking or roofing cement is not properly applied, or the shingles themselves were laid when moisture was present resulting in blistering etc.

Each inspector has to determine to what length they will go before they get into what is construed as an technically exhaustive inspection. Much of that determination will be based upon your personal experience and knowledge of various products and systems.


PS. James, excellent site for GAF products.

OPen valleys do NOT require cement along the edge. That cement develops crack between itself and the metal, and the shingles, which in turn creates channel for water to enter the system. The water never finds it’s way back out. Major leak damage occurs.
In the picture is what is REQUIRED on open valleys. The unexposed portion of the shingles must be cut paralell to the rafters to keep the water in the center.

I removed the cement on leakers and just cut the tops for repairs. I’ve also cut many tops off the shingles of leaking valleys. They quit leaking.
I’ve never had to repair an open valley done like the one I attached to this post.
I will fail a valley without the tops cut paralell to the rafters.

This picture is of my own roof. Weaved 50 year Elks. THe bottoms of each course pass at of near the valley center.
I closer look will show that I Dutched-lapped the entire roof. Elk OK’d the installation.