Traditional Roof Valley Construction

This is because the old valleys used to be galvanised and they start corroding with time especially if they trap leaves.

Traditional roof valley construction.

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. Essentially there are three main ways to shingle a roof valley. 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. In order to understand roof valley construction completely you need to know about the difference between an open roof valley and a closed roof.

Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks. Typically where a valley is located on a roof roof valley replacements are fairly common especially on tiled roofs. One layer each of felt underlayment mineral surfaced roll roofing and two layers of shingles. Woven closed cut and open.

Closed cut shingle valleys work fine with strip shingles and laminated asphalt shingles. A closed cut roof valley will have at least four layers of roof materials. A roof valley is formed where two roof slopes meet. A common misconception is that the mortar bedding is there to prevent water access.

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.