Open Metal Valley Roofing

After the self adhering underlayment is installed across the valley a pre bent metal valley lining is installed.

Open metal valley roofing.

This valley flashing material can be manufactured from any metal that will resist the effects of weather acid rain and other contaminants. If the metal expands and contracts you could get some minor oil canning but nothing that effects the integrity of the valley. Roofing shingles are installed then cut and sealed where they overlap the metal channel. Metal valley does not extend more than 8 outward from the valley whereas shingles can go as far out as you want them to.

From a more opinionated viewpoint an open metal lined valley has a cleaner and more appealing look. 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. The following photos illustrate removal and replacement of a closed cut valley with new open metal valley shingles being removed in closed cut valley.

In comparison to a closed valley an open valley adds another layer of lining into the valley. After the underlayment is placed a pre bent metal valley lining is installed. In a closed valley shingles wrap from one side of the valley to another. Ice barrier underlayment installed in roof valley.

For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck. Installation instructions often call for avoiding fasteners except clips or through slots but roof penetrations and many flashings like drip gable and end wall flashings are fastened directly and seemingly do just fine. I ve seen heater cables installed over metal valleys. A closed valley may be just fine given the budget and type of roof.

Entire width of new metal flashing properly extends over fascia at bottom of roof. An open metal lined valley properly installed is functionally better long term. Open valley when compared to a closed valley and open valley adds an additional layer of lining. The metal is usually pre painted to best complement the shingles color blend.

With a clean valley you can lay down some peel and stick roofing membrane. This metal lining can be made of any type of metal that is resistant to the effects of weather acid rain or other contaminants. Roof mastic applied along sides of valley flashing.