shinglke valley weave

[Jerome W. Young]

The valley shingles came together about 6-8 inches from the center of the valley flashing. The shingles wer enot sealed down at all. Never seen this before. Looks like poor workmanship to me. Any particular problems with the seam being out of center and not sealed?

[Rick Cantrell]

" Any particular problems with the seam being out of center and not sealed?"
By sealed, if you mean a contunious bead of roofing cement along the edge, then no, it should not be sealed. Sometimes people can cause a roof to leak by sealing the shingles down. Water needs a way to drain out, sealing along the edges has the effect of sealing the water in.
But there are problems with the installation;
The slots on the tabs should not line up.
The bottom layer of shingles should go past the valley 18" and the upper layer of shingles should be cut back from the valley 4"
or
Have an open valley using the "W" style valley flashing, and the shingles cut back from the center of the valley.

[Markus Keller]

As shown in the picture, if there is already leaves and dirt getting under the shingles, then water is also getting underneath.
It's hard for me to really tell from that close up picture what the valley really looks like.
What is the 'white' stuff underneath? Is it an alu full length valley flashing or just some tyvek?

[Jerome W. Young]

it is valley metal.

what do you mean cut back 4" rick?

[Jerry Peck]

Jerome,

Here is an Owens Corning installation instruction, go to section 3 on page 6 of 7.

http://www.owenscorning.com/around/roofing/pdfs/WeatherGuardHPInstall.pdf

[Michael Thomas]

A version of Jerry's reference, formatted for reports:

[Jerry Peck]

No comments on the drawing I referred to and Michael formatted for reports?

I expected an almost immediate response to it.

[Steve Lowery]

Do you s'pose they meant 30# felt in the valleys instead of 50#? Ive never seen it. Also it specified 2" up the valley not 4".

[Steve Lowery]

Hey, Jerry, how sore are you today???

[Jerry Peck]

Hey, Jerry, how sore are you today???

Steve,

Not too bad, my right wrist was bothering me the most (otherwise this older body bounced pretty dang well :) ), but today I have full range of movement in my wrist without it hurting much at all - a good indication that all I did was sprain it.

[Jerry Peck]

Do you s'pose they meant 30# felt in the valleys instead of 50#? Ive never seen it. Also it specified 2" up the valley not 4".

I've always seen 2", not 4", but that shows the lesser roof is cut back 2" versus what I've always read and seen previously, the greater roof is cut back 2" on everything else.

I'm curious to know if this is a mistake, or are the others a mistake, or, have the roofing industry changed the way they are doing it?

I can understand why the greater roof is cut back 2", it has more water, possibly even flowing at a faster rate, and it will meet the water from the lesser roof more than halfway past the center of the valley. The water from the greater roof will flow down over the cut back edge and the water from the lesser roof will not flow over to and under the cut back edge.

That way that drawing shows it is the water from the greater roof will overflow the center of the valley (I understand that) and then possibly up and over cut back edge, with that water, along with the water from the lesser roof, going in under the cut back edge.

Makes no sense to me.

Or am I just looking at the drawing wrong?

[Rick Cantrell]

My error, I remembered it being 4". If Owens-Corning says 2", then 2" it is.
Thanks for the correction.

Jerry
Not trying to scare you or cause you undue concern.
My father in law had a relatively minor accident. A few weeks later he had a swollen leg. Turned out to be a clot in the leg.

[Mike Schulz]

Jerry,
The greater pitched roof always gets cut unless It is smaller area then the lower section where more volume of water will hit the valley. Typically what ever section creates the most amount of water should be cut back.

Always should seal a cut valley for the reasons in that picture. I'm surprised it doesn't leak.

[Jerry Peck]

Jerry,
The greater pitched roof always gets cut unless It is smaller area then the lower section where more volume of water will hit the valley. Typically what ever section creates the most amount of water should be cut back.


That's what I've always learned too, but that drawing is from the manufacturer, and it shows just the opposite.