Tile Roof Valley Flashing

A flat tile installed directly onto standard valley flashing in a closed method restricts water in the valley flashing during heavy rains and may cause it to overflow.

Tile roof valley flashing.

Unobstructed water flow in the valley flashing is critical. This can speed degradation of the underlayment and may cause rot in the battens and decking. Closed valley s or open valleys. W valley metals designed for wood shakes and asphalt shingles do not prevent clogs and direct water into the roof system which can damage the underlayment and cause the roof deck and underlying structure to rot.

Cut the bottom edge and fold it down over the drip edge. Cut bottom of flashing so the entire width of the valley flashing extends approximately 1 2 to 3 4 over the fascia trim board along eaves the following photos illustrate removal and replacement of a closed cut valley with new open metal valley. Double ribs elevate tile battens above water flow area. There are two common methods for completing the flashing of a valley in a shingle roof system.

Extend entire width of flashing completely to the bottom of the roof valley. Make sure to cover the gap at the bottom of the raised ridge to keep bugs and ice out. There is less of a chance for leaves to gather in a spot in the valley and form a small water dam. Use roof valley cleats at intervals of 24 o c.

Should a dam develop then water may back up under the tile or shingles and end up creating a leak. W type valley flashing is more rigid for handling so it stays straight and it stops waler rushing down one side of a roof from rushing back up the other side. According to the international residential code irc valley flashing in tile roofs should extend at least 11 inches each way from the valley centerline and the flashing should have a formed splash diverter at the center at least one inch high. Using clips permits movement in the valley as temperatures change.

The installer fabricates simple clips or valley flashing cleats whose bent edge interlocks with the folded over or hemmed edges of the metal roof valley flashing to secure the valley to the roof deck. One of the details that varies between homes is the method of flashing the valley areas of the roof.