Valleys - open vs closed cut vs woven


#1

hello, what are the advantages of one type over the other? which is superior for long term reliability? seems to me that since I’ll be working alone that the woven valley would be very inconvenient, but I want to make the best choice. I’ll be using gaf lifetime. thanks in advance.


#2

Depending on what shingle from GAF’s lifetime collection will depend on what valley you need to use. Please let us know what shingle you are planing on using. That way i can best advise you on what to use.


#3

not sure yet - trying to learn more in the next thread so i can make the best choice but it’s most likely down to these three.


#4

grand timberline, timberline ultra, or slateline


#5

GTP is right, the thicker shingles don’t lend well to close cuts and are next to impossible to weave.

1. Weave- Cave man, antique way. Very rarely any reason to do this anymore. Pain in the ass to repair and IMO they look like hell.

2. Open cut- I prefer closed cut but know many people that swear by open cut. Make sure to
"crop-cut" your valley shingles and to use a raised baffle in the center of the valley if you have a pitch change in the valley greater than…hmmm 4/12? (we use baffle valley on all open cut valleys)

3. Closed cut- Best looking cut IMO and if done right the most trusted (also just my opinion). Regardless of it being closed cut I still run copper in the valley. I pop my cut line dead center and crop cut my shingles. People will argue all day about cutting off center and cementing the shingles but if done right and crop cut I’ve never had one leak.


#6

I have seen some people cut it 2 inches off center. Is there a reason for this. When you say crop cut, do you mean lifting the shingle and cutting the base of it at a 45 degree angle. This is so water doesn’t get pushed under the shingle.


#7

“I have seen some people cut it 2 inches off center. Is there a reason for this.”

Yes. It would seem to give the water more of an unabated downward movement but let’s face it, in a moderate to heavy rain that 2" is going to be worth sqwat. In my experience most people don’t "crop cut their valleys which is why they will leak.

“When you say crop cut, do you mean lifting the shingle and cutting the base of it at a 45 degree angle. This is so water doesn’t get pushed under the shingle.”

You lift a shingle and cut the top of the one under it aprox 35 degrees. This prevents the water that is running down the valley from hitting the top of the shingle and running along it and spilling out somewhere causing a leak.

Crummy pic but you get the idea.


#8

I thought that was what you were talking about.


#9

Tar Monkey is right about that. we install a lot of Tamko style vallies as well. very fast and looks good. open copper vallies are another great way to give your roof a good look. There used to be some tricks of the trade back when we did three tabs and weaved vallies but a lot of shinglers now a days only now how to do laminates LOL .
RooferJim


#10

you can use closed cut on tinberline ultra and grand timberline…not sure bout slateline or grand slate. we make our cut 1 1/2" on the steeper side of the valley to keep the cut out of the direct line of water. weave valley will void any GAF laminated shingle warranty.


#11

weaving valleys on GAF shingles voids the warranty!!!


#12

put a metal valley


#13

thanks for all replies, at this point I’m liking closed cut over metal in the valley. I would like to avoid dealing with this again in my lifetime. can you buy metal already creased down the middle or do you need a metal brake? also I have a large dormer on each side of the house. so basically I have two ridges that cross, with 4 valleys starting at the intersection. how should I layer the metal for 4 valleys at the very top?


#14

in scotland we use lead and valleys and the top is finished with a saddle am sure in america its copper but u could use a lead saddle to join the two valleys up


#15

“thanks for all replies, at this point I’m liking closed cut over metal in the valley. I would like to avoid dealing with this again in my lifetime. can you buy metal already creased down the middle or do you need a metal brake?”

You should be able to find a metal shop in your area that will do it. Ask at the local building warehouse.

** “also I have a large dormer on each side of the house. so basically I have two ridges that cross, with 4 valleys starting at the intersection. how should I layer the metal for 4 valleys at the very top?”**

Not a do it your self job if using copper because you’ll need to do some soldering. Aluminum is just ick. I don’t have any diagrams and a 4 way intersection isn’t something I can easily explain in text.


#16

lead can be bossed into any postion u want without soldering


#17

Scott, the squirrels here eat the snot out of lead on the roof (sharpens their teeth) so it’s not used much. The only time I’ve used lead was to do a “swept” slate valley or to help keep in copper counter flashing. I’d want soldering on a 4-way intersection anyways though. Just wondering if they have roof top rodents where you are.


#18

can you solder that copper sheet with a typical propane torch?


#19

An open torch makes a sloppy joint that will crack. you can solder lead or copper best with a well heated iron.


#20

really,you can get an iron thats hot enough to solder 16 or 20 oz sheet copper? maybe this is overkill. why can’t I just run aluminium down the valleys and do closed cut over it?