Valleys
In the same way water runs along the valleys between two mountains, water runs along the valleys on your roof peaks. Valleys generally receive the highest concentration of water flowing through them, therefore installing them correctly is extremely important!
As mentioned in the Leak Barrier section, valleys have leak barriers installed underneath them, this is a requirement by the Alberta Building Code.
A word of caution: Many roofing contractors in Calgary install valleys in a style referred to as 'closed'. A closed valley consists of Shingles woven inside the valley, as opposed to an 'open' valley which has sheet metal running from top to bottom. Both the 'open' and the 'closed' style of installation are acceptable by the Alberta Building Code and by most manufacturers, however, the 'open' style installation has consistently out performed the 'closed' style...and costs exactly the same price to install. Ask your Calgary Roofing Contractor to use the 'open' style of installation for your roofs valleys, this could save you from having to replace your roof system prematurely and also can avoid headaches in the long run.
Typically, an 'open' valley is installed with a 30 gauge sheet metal, 4' wide, coming in 10' sheets. This metal can be ordered in any color to match the shingles on your roof system.