A closed valley is where the tiles or shingles are butted up against each other in the center of the valley.
Open closed valley roof.
An open valley has a gap usually about 6 inches between the tile or shingles at the valley area.
The roofers apply the shingles cutting and sealing the ones that overlap the metal.
In comparison to a closed valley an open valley adds another layer of lining into the valley.
Roofing shingles are installed then cut and sealed where they overlap the metal channel.
Open roof valley this is almost the same as the closed roof valley method except a pre bent metal valley lining is installed instead of a secondary roof underlayment.
This valley flashing material can be manufactured from any metal that will resist the effects of weather acid rain and other contaminants.
The only type of valley that is unacceptable is the woven valley.
Essentially there are three main ways to shingle a roof valley.
It is always a good idea to check with the manufacturer or a certified installer of the product such as ourselves.
The metal is usually pre painted to best complement the shingles color blend.
The closed variation is a flashing that has been completely covered with shingles while in the open variation will have the flashing completely exposed to the elements.
Closed valley before you install a shingle roof the contractor will install an underlayment over the entire roof deck.
This leaves a metal strip or line on the surface of the roof that serves as the valley line.
The self adhering section acts as the lining for the valley.
Once the shingles are installed they don t run through the valley area.
Part of the underlayment includes a self adhering ice and water shield that a heavier gauge than the rest of the underlayment.
After the self adhering underlayment is installed across the valley a pre bent metal valley lining is installed.
An open roof valley meanwhile is a flashing method in which a sheet of pre bent metal is installed after the valley lining is placed.
Although the open valley is recommended by the manufacturer closed valley is acceptable.
About open roof valleys.
If you have a shingled roof as most torontonians with a sloped roof tend to have then you will have one of two kinds of valleys on your home.
Water collects in a valley to flow off the roof.
Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks.
Since the area is covered by shingles the closed valley makes the roofing system more appealing when seen from the ground.