How To Install Tin Roof Valley

Install an underlayment centered in the roof valley.

How to install tin roof valley.

Apply an approximately 3 inch width of asphalt roofing cement along the sides of flashing and embed shingles in mastic. Steep slope roofs slope greater than 3 12 cut the panels at an angle for the valley then bend the hem end of the panel and hook it with a cleat. Place them directly onto purlins that are attached to the roof trusses beginning on the outside edge. These will stop the entry of rain wind and pests.

Use 1 inch galvanized roofing nails. Roof one side of the valley running the shingles across it. First clean the debris out of the valley including sawdust nails and whatever else is in there. Attach the flashing panel in place at the bottom.

Fold the top over the roof ridge and cut the bottom along the drip edge metal. Install synthetic roofing underlayment or felt paper according to manufacturer specifications and then install the first piece of valley flashing. Install the roofing screws vertically along each rib in the panel. With a clean valley you can lay down some peel and stick roofing membrane.

Close or seal off the ends with a wood or plastic strip under the panel at each end. Secure the screws but do not overtighten. Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. Use tape sealant between the valley trim and the panel.

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. Make sure that the end of the flashing panel is perfectly in line with the edge 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. Stop nailing 6 inches from the center.

Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles. Use fasteners to attach the panel to the structure making sure that there is complete compression of the sealant. Place the first screw about 7 inches from the bottom and each subsequent screw about 18 to 24 inches apart along the vertical run.