Synopsis: This article illustrates four different methods of shingling a valley, comparing the advantages and disadvantages of woven, open metal, closed cut, and Long Island valleys and describing the author’s techniques for preparing and installing each one. A lot of today’s new home designs include multiple gables and roof configurations.
When a roof valley needs to be shingled, there are steps to take in order to make it waterproof. When it rains or snows, there is going to be more water in the valleys of the roof than in the other sections. This is because it gives a natural flow to the water as it runs off.
If you are looking to install shingles, you might want to consider the closed-cut valley method. It is popular because the two roof planes do not need to be shingled at the same time. In general, the closed cut valley method implies stretching one side of the shingles beyond the valley while those on the other side are trimmed.
The reason why the roof valley is such a vulnerable area of the roof has to do with all the rainwater and/or melting snow that accumulates and flows through the valley of the roof before draining into the gutters.
If you are looking to install shingles, you might want to consider the closed-cut valley method. It is popular because the two roof planes do not need to be shingled at the same time. In general, the closed cut valley method implies stretching one side of the shingles beyond the valley while those on the other side are trimmed.
Alternatives for the closed cut valley installation are the woven, metal, open cut and long island installation. All of these have their own pros and cons and you might want to look them up before you start installing shingles.
To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.
The price difference is overcome by the aesthetic appeal it gives to your roof. Also, they last longer and can weather any hailstorm. And yes, they are easier to maintain.
Before you begin laying down the shingles it must be protected with a metal flashing. This flashing must be about 18 inches wide for adequate coverage on both sides. Snap a chalk line down the length of the edges of the valley nine inches from the center.
This is because it gives a natural flow to the water as it runs off. Paying special attention to this will ensure that you will not have any problems with your roof after completing it. As a do-it-yourself project, it is not difficult to do, but you must follow certain procedures.
To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.
When a roof valley needs to be shingled, there are steps to take in order to make it waterproof. When it rains or snows, there is going to be more water in the valleys of the roof than in the other sections. This is because it gives a natural flow to the water as it runs off.
Because a valley collects water from two roof planes, its shingles must shed twice the water that the shingles on the roof plane above the valley must shed. Roofers secure flashing material to the roof's felt paper in the valleys prior to installing 3-tab shingles.
Many homes use 3-tab shingles as a roof covering. When a roof has two or more planes, each plane meets its neighboring plane at either a hip or valley; hips cover outside corners and valleys cover inside corners. Because a valley collects water from two roof planes, its shingles must shed twice the water that the shingles on the roof plane above the valley must shed. Roofers secure flashing material to the roof's felt paper in the valleys prior to installing 3-tab shingles. Roofers do not nail 3-tab shingles to the center of a valley's flashing.
Based out of Central Florida, Robert Sylvus has been writing how-to and outdoor sports articles for various online publications since 2008. Sylvus has been a home improvement contractor since 1992. He is a certified HVAC universal technician.
Lay all of the second roof plane's shingles covering the valley in place. Do not nail the shingles.
We're in a high wind zone so follow the manufacturer's 6-nail pattern (plus in RI the building code requires 6 nails). OC Duration shingles call for the double-nails one inch apart at 13 in. in from each end. Many companies call for 6 nails spaced at 7 1/2 in. apart. I prefer the double nails because it's easier to eyeball the 1/3 points along a shingle rather than dividing the space visually into 5 spaces.
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Tamko is the only shingle manufacturer that shows the no-cut shingle valley process in their installation instructions. I think I first learned of the system reading a bundle of Tamko shingles about 22 years ago and have used it frequently since. I checked with the technical reps from several major shingle manufacturers to see if there were any restrictions against using a no -cut valley process with their shingles, and there weren’t any — other than a caution that if the rake starter pattern of joint offsets wasn’t followed, that there may be some shading differences between shingles that would show
In my opinion, no-cut valleys are fast to install, water-resistant, and beautiful. It installs and looks almost the same as a regular-cut valley, where the shingles on the low-volume roof plane are installed first and pass through the center of the valley by at least 12 in. Then, rather than cutting the shingles on the high-volume roof plane, ...
Pro Tip: Sometimes an older roof is more prone to leaks in the valleys because of the old repairs that didn’t fully resolve the underlying issues with the roof. The sealants and roof patching materials used in previous repairs, can crack and chip away over time. If your roof’s valley leak is an old repair gone bad, then consider having a professional repair the leak properly. Note that some of the surrounding shingles and flashing may need to be completely removed and replaced, but an otherwise “healthy” roof can be saved with a thorough quality repair.
If the ice and water shield is missing, then you will have to remove the shingles on both sides along the valley, put ice and water shield in place and re-shingle the roof.
There are many factors that can contribute towards a failure of a roof valley flashing, structural issues, inadequate construction, improper roofing methods, and the roofing material deterioration.
Intact shingles create a water shedding barrier in a new and/or a well-maintained older roof. Exposure to the sun, wind, rain, and snow can gradually cause asphalt shingles to dry out, shrink and break apart. Eventually the loose pieces of roofing shingles may actually get blown off or washed off the roof.
A roof’s valley is very prone to leaks, especially if you have an older roof. The reason why the roof valley is such a vulnerable area of the roof has to do with all the rainwater and/or melting snow that accumulates and flows through the valley of the roof before draining into the gutters. Roof leaks are also very common in ...
All three valley flashing approaches use an Ice-and-water style membrane in the valley as a base level. Ice-and-Water shield is a waterproofing membrane that is applied directly to the roof deck, running from the peak of the valley (the point in which two roof slopes converge) to the gutter.
Here is a preferred method of checking: You can also put up a ladder towards the valley on the roof, lift a few shingles and check to see if the ice and water is in place. If it is missing, then you will have to make sure it gets put in place.
Self-sealing cement: A thermal-sealing tab cement built into the shingle to firmly cement the shingles together automatically after they have been applied properly and exposed to warm sun temperatures. In warm seasons, the seal will be complete in a matter of days. In colder seasons, sealing time depends on the temperature and amount of direct sunlight hitting the shingles. Hand sealing with plastic cement should be done to ensure sealing in winter.
Eaves flashing: Additional layer of roofing material applied at the eaves to help prevent damage from water back-up.
Course: A row of shingles or roll roofing running the length of the roof. Coverage: Amount of weather protection provided by the roofing material. Depends on number of layers of material between the exposed surface of the roofing and the deck; i.e., single coverage, double coverage, etc.
Also called three-dimensional shingles. Lap: To cover the surface of one shingle or roll with another. Lap cement: An asphalt-based cement used to adhere overlapping plies of roll roofing. Low slope application: Method of installing asphalt shingles on roof slopes between two and four inches per foot.
Caulk: To fill a joint with mastic or asphalt cement to prevent leaks.
Felt: Fibrous material saturated with asphalt and used as an underlayment or sheathing paper.
Mansard roof: A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables. Masonry primer: An asphalt-based primer used to prepare masonry surfaces for bonding with other asphalt products.
Sidewall flashing against a vertical sidewall (see illustration, page 5) must be continuous or step flashing and a minimum of 4 inches and 4 inches in width and direct water away from the vertical sidewall onto the roof or gutter.
Install a cricket or saddle (see illustration, page 5) on the ridge side of any chimney greater than 30 inches wide. Cricket or saddle coverings must be sheet metal or the same material as the roof covering.
Fasteners for asphalt shingles must be galvanized steel, stainless steel, aluminum or copper roofing nails, minimum 12 gage shank with a minimum 3/8 inch head, of a length to penetrate through the roofing materials and
The code in Minnesota requires this special waterproof shingle underlayment at the eaves or lower edges of the roof.
Repair or replacement of asphalt shingles damaged by wind or other events are not addressed in the 2020 Minnesota Residential Code. Repair or replacement of asphalt shingles is only permitted when complying with the shingle manufacturer’s specified installation instructions for such work.
Replace existing flashings that are part of the assembly where rusted, damaged or deteriorated. Flashing must be reconstructed to comply with approved manufacturer’s installation instructions.
Complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building’s structural system and that do not rely on existing roofs and roof coverings for support, do not require the removal of existing roof coverings.