Roof Valley Against Wall

Ideally i like to start by installing a 3 ft.

Roof valley against wall.

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. A closed cut roof valley will have at least four layers of roof materials. Metal roof flashing is a galvanized sheet metal bent at right angles with about eight to 12 inches on each side of the angle. The flat roofing material must go up the wall a minimum of 12 or up the wall and over the top of the wall if the wall is less than 12 high.

Proper roof wall abutment flashing examples. If you don t direct water from the roof into a gutter it can pour into the wall. Shingle the other side of the valley the same way. Here is an attempt though maybe not a very good one to make the roof flashing serve also as a through the wall flashing with a tile roof.

Avoiding problems begins at the beginning with a gap. A roof valley is formed where two roof slopes meet. Housewrap creates the foundation. Essentially there are three main ways to shingle a roof valley.

Sheet of housewrap or even better a piece of self adhering roof underlayment to the wall before the first truss or roof rafter is placed against it. Closed cut shingle valleys work fine with strip shingles and laminated asphalt shingles. Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks. One layer each of felt underlayment mineral surfaced roll roofing and two layers of shingles.

Stop nailing 6 inches from the center. Roof one side of the valley running the shingles across it. Ground zero for roof rot is often where roofs meet walls. Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.

Then install a non corrosive metal valley flashing of 24 minimum width lap successive sheets of metal flashing a minimum of 12 inches and seal laps. 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. Metal roof flashing can be use to seal gaps between roof walls. The sheet acts as a backup at a vulnerable junction.

Install an underlayment centered in the roof valley. Recommended procedures of basic valley flashing installation. Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. Below are two photographs of roof wall step flashing completed and effective of a slate roof against a brick wall below left and in process with step flashing against a dormer sidewall before the dormer siding has been put in place below right.

Woven closed cut and open.