Just because a roofing manufacturer allows a roofer to do something, it doesn’t mean we should do it. Make sure the company installing your new roof follows the guidelines the manufacturer recommends.
When manufacturers design roofs, they do so with a broad picture of how they will be installed. Every state has a different environment. You’re going to install a roof differently in Texas than you would here in Oregon.
Our roofs grow moss, slime and have a ton of debris. So we have to install our roofs with those things in mind. So just because a manufacturer allows something, it doesn’t mean it’s right for our area.
There’s a presidential style roof that’s designed to look like wood shakes, but it’s actually composition. With a regular composition roof, you can install a “closed cut valley.” It’s about a fifteen-year valley.
With presidential style, that’s not a great thing to do because they’re so thick. You’re just asking for problems out here. And if you actually asked this manufacturer if you could do the closed cut valley, they would allow it. But they’d recommend against it.
Before you have a roof installed, talk to the company. Ask them if they are following the rules the manufacturer allows, or the ones they recommend for your area.