Open or closed valleys

On a recent trip up north, (i’m in cincinnati) I noticed that almost every roof had a western cut valley installed. I was just wondering why?Does anyone north of Dayton use metal valleys? Down here we all use metal valleys. Are there less problems with Ice Dams in a closed valleys? I know I like the look of the western cut valley better. The only time I use a western cut valley is where 2 diff pitches of roof come together in a valley. As far as cost goes, I think it is around the same for either style. Just wanting some input, also what about down south, any metal valleys?

i have shops in both places you mentioned, properly installed a metal valley and cut lapped valley are both good the cut valley just looks better. I refuse to do laced valleys. There are a lot of metal valleys in the south more than any thing else. I believe in the colder parts of the country i have had better luck with lapped over metal , the snow seams to back up over the flange on the sides of the metal between the shingles

Closed cut valleys up to a certain thickness.

A modified bitumen valley should be laced.

A four ply BUR valley should be I dont know the name, but its pretty technical (roofboss?)

A single ply valley is none of the above.

A standing seam valley is kinda open, but not really…it is crimped

A cedar valley should be copper

A slate valley is copper-preferred.

An SPF valley is foamed and coated

A polyurea valley is 100% seamless

An acrylic valley is multi-applied and needs to be reinforced.

A thatch valley…well I dont know about that kind. :stuck_out_tongue:

from what im learnin about snow and frozen water leakin all back through the shingles , needin ice and water sheild to stop it from comin in,
1 it makes me gratefull i live and roof in tampa bay florida and 2 it makes me think
that any shingle is a stupid idea, in those climates.

use some kinda solid roof system.


Wild guess 5v crimp gweedo? Those roofs uphere are on industral and commercial building and maybe 1% of homes. It just looks like shit on a residental home.

Hey aronB you forgot the old tared valley some day i hope to grow up to be just like you. I know high quality roofing isnt for everyone.

I only do closed valleys with a single line cutback on strips (3T) & an underlaid shingle along the angle for Dimensionals.

If someone wants an open valley design (I don’t like that style, but some customers do ask for it… it ‘can’ look right IMO on a house with an English tudor style & steep rooflines)… if someone does want it, I’ll lay peel & stick under the valley.

I tell customers “Why go with a single layer of metal only when you can have metal AND shingles?”

Most all roofs I’ve done in the past 6-7 years have all been with closed valley, single cut and there has not been one leak.

Prior to that for about 3-4 years used w open valley and had a couple leaks per year always at the top of the valley were the ridge met the roof. With open valley unless you caulk or tar there will be an opening at the top of the valley.

If a house has a huge concentration of ever green or pine cone trees I’ll run painted w valley. Prior to shingling will install Winterguard on both sides of the valley, more and more builders are requiring.

Won’t weave valleys or cheat and run the shingle up and down and run short.

I forgot to mention; for those who don’t have this requirement in your state or know what “hurricane code” is for Florida, they require valley metal to have BlackJack type roofing cement slapped on both sides & top end of valley metal where it meets the felt.

IIRC, it’s @ least 4" inside the valley sides & 4" outside & over the felt as well. Gweedo can probably refresh us on that portion of Florida code.

They also require all old drip edge to be removed & new drip edge installed, as well as a complete felt removal & new felt installation.

my comin sence tells me ,
if i had to live in the snow, i would install a granulated peal n stick,
and screw some kind of decoration on top,
ie: tile, slate, somthin were the thawin water can escape underneath.

i would certainly not install a roof system (shingles), that is designed
to shed runnin water off of it,
not thawin ice.


99.9% of valleys installed in NY are closed cut & code requires (peel & stick) ice & water barrier under it. valleys differ by location…some parts of the country are all open valleys, some are all closed.

  1. Install Ice and Water barrier down length of valley

  2. Install metal valley (copper preferred)

  3. Strip sides of valley metal in with more Ice and water barrier
    and run felt paper over the valley (just like you would for an open cut)

  4. Lap shingles on low side and then the high side, cutting the high
    to finish the installation.

For the person that said, “Always use copper valley for Cedar.” you’re only partialy right. Cedar will react with copper when in an acid rain locale; read up on it.

You forgot to mention not to nail your metal valleys, but to use cleats. :frowning:

“You forgot to mention not to nail your metal valleys, but to use cleats.”

Some things are common knowledge and if they are not, well…Burger King is always hiring, lol. I’m not here to author a technical manual just toss out some guidelines.

Also while I prefer to use cleats it is acceptable practice to nail the copper valley on the edges; something like every 2-3 inches. At least according to ‘Copper and Common Sense 8th ed.’

well, then shouldnt you mention that the stuff will buckle and warp, as a warning, maybe, so that they dont think that by following your advice, their roofer jacked something up?

“Also while I prefer to use cleats it is acceptable practice to nail the copper valley on the edges; something like every 2-3 inches. At least according to ‘Copper and Common Sense 8th ed.’”

Reading comprehension is your friend.

How does the return work on that configuration?