How To Correctly Build A Roof With A Valley

It is important to get the roof construction correct at the valleys.

How to correctly build a roof with a valley.

How to shingle a valley with architectural shingles. To secure the roof valley flashing nail it down carefully. For example install valley boards flush with the rafters not on top. Then starting at the base of the valley center your first piece of flashing in the valley.

The valley rafter is marked for a 12 in 17 pitch and then cut with a double bevel to fit into the ridge intersection. Re lay the shingles you removed from the existing roof. They form an upside down v with the point at the top of the addition roof. Cut two rafters with a circular saw to the pitch of the addition roof and nail them across the rafters on the old roof.

Up from the valley center. Keeping all of the crowns pointing up prevents waves from marring the finished roof. Make sure they are properly formed. It is the upstands that prevent water from entering the roof space not the mortar.

Because most framing lumber is not perfectly straight i check each piece and mark the crown before i start cutting the lumber into rafters.