Traditional Roof Valley Construction

In order to understand roof valley construction completely you need to know about the difference between an open roof valley and a closed roof.

Traditional roof valley construction.

It is an area where water is directed towards rather than away from therefore correct detailing and construction is essential. If the roof valley which is going to be put in place is a closed valley then the person who is repairing your roof will place the roofing shingles on top of the roof deck. Typically where a valley is located on a roof roof valley replacements are fairly common especially on tiled roofs. 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.

A closed cut roof valley will have at least four layers of roof materials. Closed cut shingle valleys work fine with strip shingles and laminated asphalt shingles. One of the areas of a pitched roof most prone to leakage if not constructed properly is the valley. Essentially there are three main ways to shingle a roof valley.

Woven closed cut and open. Water collects in a valley to flow off the roof. 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. This is because the old valleys used to be galvanised and they start corroding with time especially if they trap leaves.

One layer each of felt underlayment mineral surfaced roll roofing and two layers of shingles.