Then starting at the base of the valley center your first piece of flashing in the valley.
Roof valley flashing details.
To understand what makes a valley either closed or open it is important to understand how a valley is constructed.
Install synthetic roofing underlayment or felt paper according to manufacturer specifications and then install the first piece of valley flashing.
The edge of the roof has thin metal flashing that helps water drip off the roof without damaging the home or causing a leak.
Water is a buildings worst enemy.
These problem areas include the edges of skylights and chimneys soil stacks vent fans and roof valleys as well as the intersection of the roof deck and dormer walls.
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.
Punctures in the center of the valley.
Open valleys have metal flashing to protect this critical area of the roof.
Most flashing is made of galvanized metal but diy ers may prefer aluminum flashing because it s easier to bend.
Roof mastic applied along sides of valley flashing.
To secure the roof valley flashing nail it down carefully.
While some skylight manufacturers include flashing in their products sometimes roofing professionals have to create it or purchase it separately.
Failure to extend the entire width of the metal valley flashing beyond the eave of the roof.
Drip edge metal valley flashing dormer chimney and kickout flashing are types of roof flashing that shed water away from the connections between roofs walls chimneys and other building assemblies.
Closed cut valley fully replaced with new metal valley flashing.
One of the details that varies between homes is the method of flashing the valley areas of the roof.
Only nail at the edges with only enough nails to hold it in place.
Getting the details right.
There are two common methods for completing the flashing of a valley in a shingle roof system.
Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley.
Lile points out that valleys lined with roll roofing are not as durable.
Closed valleys or open valleys.
Nrca lile recommends that roof valley flashing metal for open roof valleys should be 26 gauge 0 45mm galvanized steel or equivalent noncorrosive nonstaining metal.
Avoid the following common errors.
4 biggest roof flashing errors to avoid no matter what the age of a building there is one simple universal truth.
Extra nails may increase the risk of leaks.
