Metal flashing in valleys? 4 pitch roof

“Don’t let my reasoning befuddle you, if your going to add material you don’t need, then you should be aware of the dymanic affects it could have toward your roof.”

Mr. Gee, please go back and read my original post at the start of this thread. All the info is there.

" I was planing on using a 3’ strip of ice and water shield in the valleys and a 3’strip of roll roofing on top of that and then overlapping/weaving the shingles. Then I started reading books and most of them recommend metal flashing in the valleys. Do you pros always use metal flashing in the valleys?"

The whole point of my post was whether or not metal flashing in valleys is necessary on this roof. Most of the early responses where that flashing is a good idea. Now you say I’m installing material I don’t need. WTF, now I’m getting confused.

Go witht the valley. I disagree with my wife sometimes. Of course two roofers will find something to disagree on.

[quote=“skidstreet”]
The whole point of my post was whether or not metal flashing in valleys is necessary on this roof. Most of the early responses where that flashing is a good idea. Now you say I’m installing material I don’t need. WTF, now I’m getting confused.[/quote]

To clarify for you.
If you use Ice & Water Shield centered in the valley it is not necessary to use metal also.
You can put metal in the valley also if you would like, it is extra protection and just doing it a little better than needed, it’s a good thing.

We put 26g metal in all are valleys…never had a problem…

Yes we use valley metal all the time, but what we do is leave a gap about 2-3 inches (from the center valley line) wide on each side. You will now have an open area about 4-6 inches for water to drain off and flow into the gutter.

This is the function of valley metal as well as the pleasing asthetic looks it provides (which customer like)

You, on the other hand, are going to completely cover the valley metal. I am just saying…as a precaution…install an extra strip of felt over the metal to negate any potential condesation issue that might arise.

uderlayment, then valley metal(so knucklehead can step in valley and not pop hole in roof), then shingle.

love the tar caulking Ax.

a brilliant mind at roofing .com indeed.

gweedo.

“Yes we use valley metal all the time, but what we do is leave a gap about 2-3 inches (from the center valley line) wide on each side. You will now have an open area about 4-6 inches for water to drain off and flow into the gutter.”

Hello Mr. Gee. Yes I’ve been seeing more of these open valleys lately. Actually they look pretty good if the installer takes the time to make sure to keep the shingle cuts straight and parallel to the center of the valley. I think why so many around here use the weaved valleys is the constant hail storms we get. It makes sense to put as much material between the roof and the inside as possible. It might make the difference between a damaged roof with a slow leak and a baseball size hail stone landing on your living room floor, which actually does happen from time to time.

One question on the felt . I was already planing on running the felt through the valleys and and extend 12" up on the other side. Is that OK or do you mean I need to run a seperate piece of felt staight down the valley?

IF condestaion does form, it would run down the valley…

[quote="do you mean I need to run a seperate piece of felt staight down the valley?[/quote]
this is what we do…[/quote]

Nice cut Ax. No brainer on the cut, and the caulk is a nice touch, and it’s in the correct place.

For the record here!
Valley wood isn’t always cut on a 2x. Often as not, the roof is sheeted, then some bozo adds in an el and there is no nailer, per se. The 8cc are then nailed through the plywood, or sheathing and into plywood or sheathing.
There is a moral here. When done as I described it, the nails can and will often back out! This even happens it there is a true nailer in the valley. The metal is a better barrier to the nail coming through the roof. So metal is considered a MUST by some of us. After that decision, which is ano-brainer, is made, it’s open to style, custom, installer whether or not the valley gets weaved, Cali-cut, open, or whatever you want to call it.

If I am going to roof the valley …it would be

Ice and water…down the valley
valley metal
felt…run through and over the valley metal
Weave your shingle through

in this order.

read my next post

RooferR…

Condensation should never form under or between layers of roofing material. And I cannot accept the water runs down hill concept. (or straight down the valley_…why???

Once condensation starts and builds, it will move horizontally until it can move down. Once it moves down it will most likely stop and move horizontally again and so on until it reaches an entry point into the structure.

It is not uncommon to find a leak (in the structure) in one area, then follow the trail 5 ft up and 5 ft to your right (where the condensation begins or is the actual entry point for water infiltration.

Roofer Gee - Where would the condensation go when it hits the bottom of the felt in the valley? Is its escape route down the valley? Wouldn’t this be trapping the condensation even more so in the roof system?

I don’t want to beat this subject too much so here is my final thought…RooferR

If condensation happens to build enough between the shingles and valley metal where gravity takes over…then the moisture will most definately begin to flow down the valley metal. At some point, it is possible that there is a pressure point that stops the moisture.

The moisture will build there and begin to move horizontally toward the felt (away from the valley). We all know that once that happens…moisture will find a way throught the felt and decking. Since the decking is 1 x 8 …I can expect numerous gaps for moisture entry.

Hey!!! My motto is to “just roof it man!” But sometimes you have to put a little thought in what you are doing.

Roofer Gee - I’m picking your brain; not a fight. What you are saying makes sense. I just don’t understand how the felt helps. I’m always looking for the better way… If you ever get a chance to take a pic of a half completed valley the way you do it can you post a pic? I could just be missing something here.

Nah…that is not how I roof the valley. But if the homeowner is going to to do it that way, then I want to provide the best solution I possibly can.

I don’t see a point in covering up the valley metal with a weave. I typically felt the valleys, slap the valley metal in, shingle a “cali” of cut valley. All while applying the different manufacturers reccomendations…I.E. cut ears, bead of mastic on each side, and sometimes overlap the valley metal 6 inches with another stip of felt (leaving enough room to install the bead of mastic)…and so on.

reread your post again…the extra strip of felt will act as an extra vapor barrier between the valley metal and th shingles. This being placed ther… condensation will have difficulty forming.