The valleys must be carefully sealed along their entire length. To help prevent water from entering these vulnerable points, install a self-sealing bitumen membrane or equivalent along all valleys and properly integrate this membrane into adjoining roofing materials. Valley Seal is an innovative product that helps preserve roof valleys and ensures they work as they should. Valley Seal eliminates the need for expensive cement beds.
Closed-cut valleys begin with a row of ice shields installed in the center to serve as a waterproof coating. The “joint” effect of the ice shield that seals each and every hole in the nails that pierce the membrane is, in effect, the last line of defense in its valley. This coating is very important for maintaining a trouble-free valley. Then, the shingles are installed on the lower slope (or on the slope with the lowest water flow rate).
These shingles will overlap the valley. Next, shingles are installed on the highest slope through the center of the valley. Finally, the tiles of the highest slope are cut following a chalk line 2 outside the center. IKO's recommendation is to install laminate shingles, or architectural shingles, using the open valley method, to obtain the best roof performance.
Ultimately, placing any tile in a valley can restrict the proper flow of water and debris, unlike the metal gaskets used in an open valley. If the installer is not able to know things like that a closed cut valley must be cut two inches from the center to work properly, or that an open metal valley cannot have shingles that are cut at one end (they must be chamfered), problems will most likely arise. Let's take a look at Valley Seal and how it can help keep your roof in the best condition for the long term. To achieve an installation in a woven valley, a roofing professional places shingles in the valley and weaves them together.
The method of installing woven valley shingles does not require cement for roofs, but rather relies on the fabric pattern to protect them from water infiltration. In addition, the National Roofing Contractors Association explains that low-slope roofs are good candidates for open valleys because they are more likely to accumulate debris. Dry valleys look and work better, and for maximum performance, you can maintain them with Valley Seal. When installing the roof tiles in the background of the roof, let them lean over the valley above the first roof tiles.
For the same reasons that closed valleys use an ice shield, open metal valleys also begin with a row of ice and water shields that serves as a waterproof coating. For this method, the last shingles on the “cut” side of a cut valley are actually installed laterally, so that they go up and down the valley. Place more roofing cement on the top and bottom of the patch, where it extends over the original piece of the valley. Tessaro says: “As long as the rest of the shingles have been installed correctly and are working properly, my experience has been that an open valley system is better maintained over time.
Choose 26-gauge or thicker galvanized steel, or another non-corrosive metal that won't stain the roof, as the underlayment of the valley and will last at least as long as the roof itself.