Roof one side of the valley running the shingles across it.
Open valley on a roof.
Open valley shingle installation makes use of the metal flashing sheets that need to be installed so that they overlap each other by few inches with the upper piece of sheet is resting over the bottom piece.
Roofing shingles are installed then cut and sealed where they overlap the metal channel.
First clean the debris out of the valley including sawdust nails and whatever else is in there.
When compared to a closed valley and open valley adds an additional layer of lining.
That flashing is left exposed so the roof has visible lines of metal running down the valley.
The metal is usually pre painted to best complement the shingles color blend.
The valley area of a roof the straight lines formed when two different planes of the roof meet is a critical area that handles a tremendous amount of water run off.
Valleys are typically found where gable dormer roofs meet the main roof or when a house has angled wings or additions where two roof sections in different planes meet.
This allows water to fall from the higher slope to the lower slope and prevents it from going under the shingles to the roof deck.
With a clean valley you can lay down some peel and stick roofing membrane.
Stop nailing 6 inches from the center.
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.
During its installation process the open valley shingle utilizes the w metal flashing which helps in preventing the water from rushing down.
Pros of open valley shingle installation.
Shingles are cut on the higher slope in a straight line through the valley.
This leaves a metal strip or line on the surface of the roof that serves as the valley line.
Fold the top over the roof ridge and cut the bottom along the drip edge metal.
Some homeowners do not like the look of open valleys while others feel the metal accentuates the roof s shape particularly if copper or painted flashing is used.
Shingle the other side of the valley the same way.
Once the shingles are installed they don t run through the valley area.
For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.