Looks like a “western cut” valley as a “room addition/roofer” explained to me once. The shingles lap underneath on one side of the valley. My old house leaked there when it rained real hard after they added on a sunroom. The underlap was not enough. Needs to be at least 8 inches.
Drip edges are not done around here but might be required up north.
By second layer, I assume (I know I should never use that word) that this is what we call a roof over. If so , the you would not see the valley metal unless you can see it under the first layer at the edge of the roof. That is a woven valley, which is quite common.
Are you sure that is a second layer of shingles. Usually dont see that with a ridge vent. At least here in Fl, ridge vents are a fairly new phenonemon.
Also, usually with a roof over there should be a drip egde present. Maybe you guys in Ohio do it differently than us Southern folk.
This is a single cut mitered valley, one side should extend 12 to 16 inches past the valley transition. the opposing side is then cut along the transition line, hence, the single cut mitered valley. Valley flashing on this type of roof can be seen at the leading edge where it falls into the gutter. Valley flashing is to reinforce the transition ( or bridge the gap ) where roofing does not generally conform to the substsate. It keeps you from tearing through the roofing if you step on it or a tree branch falls there, by forming a flexable yet reasonably solid substrate.
I agree with Jae. Lack of drip edge shows Regardless of the climate, it helps preserve wood fascia and trim, cuts down on maintenance costs, and saves the homeowner money in the long run. They don’t install it that often around here, either, but that doesn’t mean they shouldn’t. I always call it out and explain my reasons for doing so. What do roofers and builders think, they make that stuff just to sit on the shelves at Home Depot?
This is a closed cut valley (picture is from the wrong angle and not close enough to be 100% sure) or maybe a california.
The concern here is none, this is an acceptable means of installation and it is not recommended that metal be installed prior to the shingles, however it is recommended that ice & water shield or a roll product is installed on the deck prior to the installation of the valley detail.
The details for this installation can be see at www.certainteed.com if you care to see it. The type of shingle you will look under will be called Landmark.
I will point out that one post noted that the shingles must underlap at least 8 inches, the spec is that they carry over not less than 12 inches and nailing in the valley must be kept out about the same.
Problems to look for with any valley is leaking of course, look also for poor workmanship which should have you look closer as you may find that the parts that are not readily visivle will be installed improperly too.
The shingle in the picture is a Certainteed Landmark in the color Colonial Slate, the product could be a 25 or 40 year product and is likely to be 5 years old or older. The black shadow highlights on the cap shingles and the field shingles are distinctive to this product
Note, with the type of shingle pictured, architectural/dimensional, call out when the valley is installed with a full weave! problems can occur when installed using the full weave and the factory spec’s recommend against this method
Concerning the drip edge it is the 2nd question on the NACHI Roof Exam. What is the flashing between roof covering and sheathing around the roofs perimeter? Drip Edge. In the lesson, under flashing systems it states " All eave and rake edges need a flashing to prevent rain water from wicking into the roof". It is the reason the edge flashings is referred to as drip edge. In the classes I’ve taken it always says there should be flashing around the full perimeter of the roof. Also here in southern Illinois we’ve been doing it for many years, I’ve installed many asphalt roofs and have always used it. Beside protecting the roof it gives you a straight edge and is the cheapest component,
And the next best Valley to David is the St. John Valley of Northern Aroostook County, Maine. Where you throw a rock in New Brunsick, Canada.
A mile from Town is a Parish by the name of Saint David, in the Valley.
After 40 years of roofing and chasing leaks and damage, I can assure you drip edge is not a cure-all. Runing the shingle 1-1/4" to 1-1/2" over the eave will suffice nicely and never cause damage.
Now, a drip edge only sticks out 1/2" and shingles run flush to it will allow water onto the fascia and water will wick under it too.
When I use DE, I run 1-1/4" past it. Here’s a picture of mine with DE and the 1-1/4" over.
In the second picture, you can see where the water quit following the shingle bottom.
That’s not flashing below those shingles. That’s the gutter back. And it’s the new improved way to build houses;
Use osb. Stop the sheathing at or behind the rafter end;
It’s hard to close those gaps;
Notice that the starter course is a reversed shingle? No sealant on the bottom edge at all. It’s supposed to be a 3-tab with the tabs removed to supply a sealer strip on the bottom edge. AND, the nails need to be in the starter just 1" up into the osb. As it is, a good wind will blow the bottom shingles off.
Which leads to another issue. The decking is unsupported because it stopped at the rafter ends, instead of the old, wasteful method of extending it over the fascia, which would support the decking. Now when you try to drive nails into the bottom edge of the osb, the osb breaks up and the nails don’t have anything solid to hold them there.
How much shingle overhang do you have? 1 1/2" will work for water. Ice will get into the soffit there…
Correct, the “flashing” is the back of gutter bent over, leaving approx. 3/4" gap between the facia and decking.
At the most there is a 1" shingle overhang. Even if rain water would drain properly, here we get our share of snow and ice, that I think the osb would soak right up. Also wind driven rain would be an issue.