How To Install Tin Roof Valley

Roof one side of the valley running the shingles across it.

How to install tin roof valley.

Place the first screw about 7 inches from the bottom and each subsequent screw about 18 to 24 inches apart along the vertical run. Stop nailing 6 inches from the center. The washer under the screw head should seal to the surface of the panel without bulging or shifting. Lay the flashing down in the roof valley and start at the lower end of the roof.

Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. Use fasteners to attach the panel to the structure making sure that there is complete compression of the sealant. Apply an approximately 3 inch width of asphalt roofing cement along the sides of flashing and embed shingles in mastic. Use tape sealant between the valley trim and the panel.

Shingle the other side of the valley the same way. Close or seal off the ends with a wood or plastic strip under the panel at each end. These will stop the entry of rain wind and pests. 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.

Install the roofing screws vertically along each rib in the panel. First clean the debris out of the valley including sawdust nails and whatever else is in there. Use 1 inch galvanized roofing nails. Install synthetic roofing underlayment or felt paper according to manufacturer specifications and then install the first piece of valley flashing.

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. Place them directly onto purlins that are attached to the roof trusses beginning on the outside edge. Secure the screws but do not overtighten.

Attach the flashing panel in place at the bottom. Install an underlayment centered in the roof valley. Fold the top over the roof ridge and cut the bottom along the drip edge metal.