20" Galvanized valley or rolled roofing?

I have 2 bids right now for a roofing job and they are very close in price. One of the contractors states that he will use “20” Galvanized metal in all valleys" and the other says “90 lb rolled roofing in all valleys”. It sounds like the metal is a better way to go but is it? Also, the guy with the 90lb rolled roofing states that he does a “double ridge”. Again, does this really matter?

I’m going to get a third quote since that’s what I see recommended here. I’m also adding 5 turbines since I have only flats now and not nearly enough ventilation in my attic. I have about 2200 sqft under roof and 7 flat vents which I don’t think is nearly enough. So, I’m going with 5 turbines and 2 flats with this next roof.

Thanks for any and all comments.

Definitely not the 90# guy, there is no good reason for 90# rolled roofing to even exist anymore…
Is this guy selling you IKO shingles with no felt also?
I bet he has a big ol’ bucket of tar in his truck also… :roll:

The 20" galvanized metal is probably really aluminum, this alone isn’t much better…

What you want in your valleys is Ice & Water shield.
If you are in a cold climate you want this on your eaves also.
If the metal guy is going to put the metal over the Ice & Water shield, this is good. :smiley:
Though Ice & Water shield alone is sufficient.

My personal preference is 24" metal W Valley. It is metal with a ridge down the middle. This stops wind driven rain from blowing all the way across the valley into the tabs of the shingle. It also looks the best (in my opinion) Lots of guys like using 90 lb and may use an open valley or weave the valley over the 90lb. Once again, given a choice, I would weave the valley over the 90lb.

I would look at some of the old postings on this site about ventilation, but the bottom line is you should look at eave/ridge vents to get the most out of your ventilation. Nothing to wear out or break.

I should have noted that I live in North Texas if that makes a difference. Doesn’t get very cold here and the average life of a roof in this area is about 6 years due to hail.

I thought 90# roll roofing for valleys went out over 30 years ago, before Ice and Water Shield came into play?

Throw that guy a spec book with current standards.

Double ridge doesn’t matter. It may give a higher profiled appearance, but that is it.

Why don’t you forget about the whirlybirds and have the Shingle Vent II Ridge Vent used on the ridges. This way, you get the maximum out of the ridge line for exhaust ventilation and you also get a raised profile appearance on the ridge.

Remember, you need an equal or greater amount of Lower roof or soffit Intake ventilation to make any exhaust venting system work properly.


metal in valleys.
its one corner i cant even cut…


Okay this has really helped me out. I appreciate the feedback from everyone. I’ve got another estimate scheduled in the next couple days and this will help me ask the right questions.

what only i find that amussing.


I was slow on the pick up last night Gweedo.

Yeah, I liked it the second time around.


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I got a kick out of the name of the Island where you met your wife.