How to Shingle a Valley

Essentially, there are three main ways to shingle a roof valley: woven, closed-cut and open.

Is valley flashing necessary?

The valleys see the most water flow, as water from both surfaces gathers in the valley as it runs down. The extra layer of flashing in the valley helps protect it from water intrusion. Metal flashing, which is most often used, also helps the water move more quickly off the roof, and even the occasional snow.

Which side of the valley do you shingle first?

A valley shingle is then installed parallel to the centerline and offset a couple of inches. Shingle courses are installed starting at the bottom. Each course is started at the valley, aligning the bottom corner of the first shingle on each course with the edge of the valley shingle nearest the valley centerline.

Which is better open valley or closed Valley?

closed valley roofs, IKO’s roofing experts believe that open metal valleys are the better performer. This roof upgrade to an open metal valley gives your roof better resistance to water penetration. Plus, open metal valleys shed debris, snow and ice faster than any roof valley type that uses shingles in the valley.

How wide should a roof valley be?

Lead-lined valleys

The most common open width for a traditional valley is 125mm and this is generally satisfactory for normal domestic roofs. There are exceptions, such as low roof pitches and/or long rafter lengths and further guidance for these is available in the Lead Sheet Training Academy (LSTA) manual.

Can you weave a valley with architectural shingles?

Here we have a laminated shingle roof that has been installed with a woven valley detail. Woven valleys should only be used with strip shingles. This is an incorrect installation of this type of roofing material and will be more prone to water intrusion and will void the manufacturer’s warranty for this material.

How do you seal a valley on a shingle roof?

Apply a bead of roofing cement around the outer edge of the patch slide the patch under the shingles on one side and then the other. Put more roofing cement on the top and bottom of the patch where it lays over the original valley piece. Smooth the cement so water can flow uninterrupted down the valley.