Valley shingle installation practices

Comments/concerns? Thanks.

“Woven valley installed incorrectly. May leak. Recommend correction by a licensed roofer.”

Did you find any evidence of water intrusion inside?

No. House built in '99.

Dimensional shingles are prone to cracking when bent, at the joint where they join the 2 pieces together. It is common to close cut the valley ,weaved valleys are not very common but have been accepted . A good underlayment is needed and could be viewed at the bottom of the valley.It does look like they ran too high and that will hold moisture.

Improper Woven valley.
Although it might not leak, the installation is not correct and visible nail penatrations tearing the tab is visible.
A Woven valley with differing pitches is somewhat more difficult than dormer and main roof with the same pitch.
It is obvious, that this installer did not know the correct procedure.
It is more of an aesthetic issue than a leakage issue. :slight_smile:

May be not in Florida but they are very common else where… over 90% of the homes I inspect (and build) use this technique… like anything when not done correctly there can be problems.

In a nut shell, woven valleys are accepted by the manufacturer.



Full lace vallies were the norm for many years. Problems I had encountered was trapping of debri and moisture penetration at low nails and Ice damming. Carpenters roofed this way and roofers cut the valley. Some used 90 pd., metal, or nothing at all. as underlayment.

Hi Marcel,

I see the exposed nails did a number on those shingles, but if nailed and sealed properly aren’t nails allowed in the last shingle of a row of caps?

Installed wrong! call it out…in time these valleys will fail and leak.

The weaving is just wrong in multiple courses.
Because of the steep pitch of the dormer, it should of been a cut or open valley.
Years ago, they were all weaved, but they did not look like that.
Weaving is allowed by the manufacturer.
The ridge caps were not run far enough to the main roof, so when they tried to nail the tabs, it tore through.
Hopefully they have the valley well flashed with SA Flashing underlayment.:slight_smile:

Not true…while the roof in question was a crappy job…woven valleys do indeed perform fine… .again when done properly. I have lived here in the Carolina’s for over 20 years… have replaced hundreds of roofs that did meet their service life…as with anything it comes down to installation.

The times they have failed was either because of wrong installation (as is this case), mechanical intrusion (man made) or simply external force such as hail or tree branch striking same.

I have my crews install ice and shield dam in all valley as well as the valley of a transitional slopes. That product works great.

I’ve always considered a nice woven valley a sign of a highly competent roofer. When I see a cut valley, I think he may be a rookie and I look a little harder for defects.

(This one is not nice, however.)

Video here that might help some on woven shingle valleys.