Open Valley On A Roof

An open valley relies on metal flashing for protection.

Open valley on a roof.

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. Once the shingles are installed they don t run through the valley area. 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. For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.

Stop nailing 6 inches from the center. This leaves a metal strip or line on the surface of the roof that serves as the valley line. That flashing is left exposed so the roof has visible lines of metal running down the valley. First clean the debris out of the valley including sawdust nails and whatever else is in there.

Fold the top over the roof ridge and cut the bottom along the drip edge metal. Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. When compared to a closed valley and open valley adds an additional layer of lining. Install synthetic roofing underlayment or felt paper according to manufacturer specifications and then install the first piece of valley flashing.

Roof one side of the valley running the shingles across it. Shingle the other side of the valley the same way. 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.

Shingles are cut on the higher slope in a straight line through the valley. 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. 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.

With a clean valley you can lay down some peel and stick roofing membrane.