Valley metal


#1

hello, which would be your preference for metal under a closed cut valley? .00925 aluminum, or .010 galvanized? can’t afford copper. thanks in advance


#2

That’s some pretty thin aluminum there. Seems like it would buckle, warp and wave


#3

what about alum vs galvanized in general?


#4

Galvanized will rust, aluminum will not. Try 026 ga. aluminum.


#5

Hi,

In a closed valley there is no need for valley metal. There is nothing wrong with putting it in, but not necesary.


#6

Ice and water shield is much better.


#7

[quote=“Lefty”]Hi,

In a closed valley there is no need for valley metal. There is nothing wrong with putting it in, but not necesary.[/quote]

It’s code here in Minnesota. Even on a two foot valley with a cali cut you have to have valley metal.

Nail guns blast through most aluminum flashing which is why I never use it. 26 gauge 20in wide rolled galvanized flashing works pretty good. Aluminum will cost more than steel.


#8

I went with galvanized steel under the closed valleys with my roof (I’m a DIYer). I don’t like aluminum because of its thermal expansion properties. I imagine it could be a problem with thermal cycling over the years.


#9

I went with the thin aluminum in my valleys. I used ice and water first. The only reason I used metal was because of the codes. I actually figured that a thinner metal would have less buckling. That stuff is so thin I didn’t think it could push up a 40 or 50 year shingle. Did I make a mistake? I added way too much underlayment in the valleys. I hope this doesn’t become a problem. I used ice and water and then used thin aluminum and just went over that with my normal felt runs.


#10

if water gets past the shingles and gets to the valley
metal its not going to matter what it is made out of.
it is going to rott and then leak.

worry about putting a roof on were the water will not
get to the metal, and you wont have to worry about what kind of metal to use.

gweedo.


#11

Proper way to lay a closed cut valley for asphalt shingles IMO is:

  1. Ice and Water Barrier directly to the deck. Running down and centered in the valley (full width).

  2. Metal (copper preferred) Make sure you install copper with clips so it can move. Other metals should be pinned in with nails at the edge that touch but do NOT pierce the valley metal.

  3. Felt underlayment running at least least 4" into the valley metal.

Metal on a closed cut valley serves several purposes. Not the least of which is protecting the valley from cornballs stepping into it and causing a leak.


#12

interesting tip about catching only the edge of metal with nail heads. so with 20’ metal leaving 10" per side are you also making sure you don’t nail shingles within 10" of the valley centerline in order to avoid piercing the metal?


#13

You dont need metal under a closed cut vally,just I&W shield. waste of material and a fools errand unless your going to show the metal.

RooferJim


#14

I agree .

Clean valley and no nail heads poking up will be nice for I&W shield


#15

i put the nails in the valley metal bout 2" from edge , bout every ft or so, nailed in tightly,
then when nailin shingles up the valley i try to get the nails to perce the valley metal again.

gweedo


#16

“interesting tip about catching only the edge of metal with nail heads. so with 20’ metal leaving 10” per side are you also making sure you don’t nail shingles within 10" of the valley centerline in order to avoid piercing the metal?"

I don’t pierce valley metal at all except for 1 or 2 nails at the very top which become overlapped with the next piece of valley laid in. IMO there is no reason to pierce exposed metal either, there are just too many ways of clipping or locking it. Only exception I can think of is maybe a masonasry fastener like a Zamac, which if you want to get crazy you can solder a cap over it, lol.


#17

aluminum should last the same amount of time as your shingles i cant see u having any problems


#18

[quote=“Lefty”]Hi,

In a closed valley there is no need for valley metal. There is nothing wrong with putting it in, but not necesary.[/quote]

Yeah but the valley metal looks better.
On all the upper scale homes we use galvinized valley metal that is painted to match the shingle color.
I prefer to use valley metal on all homes even if they dont want to pay for it. Id still use.
I use specially treated galvinized meatl colored to match the home so it looks all fine and dandy. Closed cut valley i can down them enough.


#19

we always use lead in our valleys , valleys are a weak point on any roofs and a good metal should be used in them


#20

Hi,

How can valley metal look better in a closed valley?

You can not see it.