Valley flashing vs weaving

I just got a quote from a roofer for a duration premium shingle. The quote says that they will weave the valleys instead of using flashings. Is there a reason for doing this with this particular shingle instead of using flashings? Thanks.

1 reason: it is cheaper, 2 it’s less work.

Metal valleys are better than a woven valley in my opinion (and probably most others). They look better and last longer.
See what his price difference is for metal valleys.

thanks. I just looked at a picture of a woven valley and it looks cheap. The other picture I saw was of a closed cut valley and it looked nice. My worry is leaks. Am I right to assume that an open valley has the least chance of leaking?

I put on the weave with some 3-tabs but could imagine the big narly bulky mess that weaving a 30 would look like, I have seen some open valleys that look pretty hideous too.I feel it depends on the type of metal and who is installing it but like the demon said cheap and less effort. If your pitch is above an 8/12 I like the appearance of copper but its a little pricey but looks awesome. :idea:

If done properly, yes I would say it has the least chance of leaking.

no, the pitch is only 7/12. THink I’ll find someone who will give me the option of metal valleys. Thanks!

I hope I didn’t throw you off about the 8/12 being the best for open valleys, any pitch above a 4/12 could have open valleys but I inquired about the pitch because an 8/12 and above would make it worthwhile for the viewing of the investment for the copper valleys.

weaving is really only intended for tab shingles. It dosent look very good with laminates.

I know GAF is pretty clear that they do not approve weaved valleys on laminate shingles. I know certainteed will except them and who knows about OC?

Whats going to last longer if done right?..26gauge metal or shingle?..hmmm

i think weaving looks awful.

Roll of valley metal… then do a closed cut valley so the metal isn’t exposed.

Why is this good?

  1. The water runs down the shingles.
  2. If water does happen to get under the shingles… it runs down the valley metal.

Some Manufactures Recommend using ice and water shield instead of valley metal.


Why is this good?

  1. If water does happen to get under the shingles… it runs down the valley metal.

That defeats the purpose of a quality roof installation.,might as well provide your customers with 5-gallon buckets to catch the water running off the rafters.

When and if the water gets behind and under and around and thru the shingles it is then trapped and causes premature blistering causing roof failure in that area.I agree with you about the moisture guard makes more sense than a roll of aluminum.[/quote]

I think Sheathing nails can poke up through most of your moisture guard/Ice and water shield underlayments. Just my opinion. But it is an acceptable way to do it in some/many regions.

I like to have two plys of a quality paper in the valley. I dont always two ply it. That would depend on the condition of the valley and the pitch also. Then 20 inch 26g galvanized steel.
Then a couple different styles of closed cut valley covering the metal. Not woven.

I’m not a huge fan of valley metal. However, I can’t see a weave with a Duration shingle. I would think you would install ice & water followed by a closed cut valley. Guys can diss ice & water if they wish and call it a bandaid or insurance policy but the fact is, it works.

A leak in the valley may not necessarily be the result of bad workmanship. What about the guy who ends up with a major pine needle dam in a valley with several gallons of rain water trapped above it for an extended period of time?

I’m not a huge fan of bandaids or “insurance policies” but when I can invest a $100 to $200 in something that works that can save $500 to several thousand down the road, count me in.

Roofmaster, Your absolutely right. But… I still think its always better to be safe than sorry.

Look at it this way.

Lets say one of my crews make a mistake one day in a valley(which i dont see how). Its better to replace a couple of ruined shingles than to replace plywood, insulation, sheet rock, painting, flooring, and an art painting that is priceless hanging on the wall…

lol… Anyways, I havent had any issues with our closed valleys. Its probably due to our quality roof installation.

Also if a storm rips some shingles out the valley… it will still be protected.

Great Example.

Water runs through pine needles.
For me, a valley is the last place the roof would ever leak.

But i live in florida. Our goverment codes dont allow it any other way.
In the new construction business. No shingles are allowed to be installed untill a city inspector comes and sees that you have put rolled valley metal in.
Ice and water shield alone would fail.
So we dont even get to make that choice.
Go Go Government… :roll:
How do you like freedom just slipping away???

I do see the great value in installing it in areas that get snow and ice dams.

[quote=“roof-lover”]Water runs through pine needles.
For me, a valley is the last place the roof would ever leak.

ESPECIALLY in florida,actually believe it or not I enjoyed roofing there.,after the hurricanes in 05’ I can say that your great state made me a better roofer.I could have done something different with the gals in the building department in lake and seminole county but had no problems with miami/dade orange,marion or osceola counties a very pleasant experience.,but hot HOT,HOT,HOT and you could set your watch with the afternoon rain.Would not have missed it for anything.VERY STRICT CODES and enforcment too.,seperates the men from the boys.And the roofers from the installers.[/quote]

Rolls of valley metal :shock:

Hopefully they are talking about that thin junk from lowes or home depot and they install it in the valley either under or over a course of felt along the valley line, then shingle creating the closed cut valley, and hopfully they don’t use that for an open valley.,anyway you look at it W is the way to go.