what are the pros and cons of weaving valleys as opposed to cutting them?
The looks The time and The preferance.
Weaving is the antiquated style of doing things. A closed cut valley is the new and improved version. From time to time you do come across a problem area that requires a weave but it’s very rare.
Pros: Ummm… Water can flow from either direction and there is little chance of it getting up and under the shingles. This is it’s only saving grace over any other style of valley but as I already stated, you very rarely encounter an area where you actually need this attribute.
Cons: Takes longer to install as you need to run both sides of the valley at the same time.
Very difficult to repair.
Many of your thicker shingles cannot be woven.
Pros: Fast install.
Much easier to repair than a weave.
Cons: Have to do a lot of cutting.
If you don’t “crop cut” your cut side it may leak.
Some of the thicker shingle cannot be closed cut.
FYI * Do not confuse “closed cut” with “California cut”, they are two different things.
weaved valleys also usually fail prematurely. i believe it now voids warranties from certain manufactures.
In addition I don’t like the weaved valleys because it tends to trap debris (leaves, dirt, granules) in the valley. When we cut our valley we don’t cut it in the joint of the valley. We cut up an inch or two so it doesn’t catch all the debris from the trees and such.
I was getting ready to admonish you, but you saved yourself by differentiating between cut and California cut, which is not a recommended valley and if frowned upon by NRCA, ARMA and others. For example, GAF/Elk will let you install the California-cut on their Timberlines but I believe not the Prestique, but the slope must be greater than 4:12 AND MUST MEET LOCAL CODES. In other words, they would rather roofers not install California-cuts, but they know people are going to do it anyway so the manufacturer tries to set some parameters. Hardly a ringing endorsement for the California-cut valley.
To keep the woven valley straight, it is best to have equal pitches, and of course equal course exposure on either side.
Since so many modern houses have unequal pitches, it would be a nightmare. Not only would you be constantly adjusting exposure, to say the least these adjustments would be exagerrated.
So not only would you lose the shadow lines, which pappy and grandppay never had to worry about, some courses might even be extremely short
when they meet even for closed-cut valleys sometimes they can even be a problem (point of the shingle doesn’t meet the edge of the ice guard) i like open valleys on older steep roofs because here in pa seems that the closed cut tend to darken quickly. however for low slope i still use closed-valleys. Open valleys you can run upside-down courses up the valleys color-side out and run the shingle in square to its really fast and it looks really good … i can post some pictures if you’d like
Open valleys you can run upside-down courses up the valleys color-side out and run the shingle in square to its really fast and it looks really good … i can post some pictures if you’d like
That my friend is called a “California cut”. meh
[quote=“Tar Monkey”]Open valleys you can run upside-down courses up the valleys color-side out and run the shingle in square to its really fast and it looks really good … i can post some pictures if you’d like
That my friend is called a “California cut”. meh[/quote]
yeah…and it typically voids a warranty (its called cutting a corner)
Roll valley first choice with one cut which is either on the roof that’s larger than the other or on the roof thats 2+ pitches greater than the other. I try to cut down the middle as much as possible but on long valleys with a big pitch change I like to kick out the bottom by an inch or two. Also all corners are cut back on the cut side.
Next choice would be painted open valley.
Never have and never will weave a valley.
notched metal valleys far easier, and quicker 2 install. look far more professional AND u ever seen the water hit the metal valley? it runs straight into gutter faster than u can fall off the roof hahahaha.GO METAL