Metal Roof Valley Overlap

One layer of shingles actually crosses the valley beneath the other.

Metal roof valley overlap.

How to seal metal roof valley. Install an underlayment centered in the roof valley. Where two roof valleys meet for example above a gable dormer a soldered joint is likely to break from the movement. Metal valley will last forever.

Provided the rest of the roofing shingles were properly installed and are performing properly my experience has been that an open valley system holds up better over time tessaro says. To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap. Lap successive sheets of metal flashing a minimum of 12 inches and seal laps. Install metal panels or shingles align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof line.

Apply an approximately 3 inch width of asphalt roofing cement along the sides of flashing and embed shingles in mastic. It is essential to only use whole not cut shingles during this step. Then install a non corrosive metal valley flashing of 24 minimum width. Best practices for sealing the metal roof valley vary based on the slope of the roof.

Fold the top of the flashing over the ridge and nail it off every ten inches or so along the outer edge of the flashing now this valley will carry water off the roof and away from the house. The installation of metal roofing involves placing large metal panels on the roof. The panels overlap allowing water to flow from one panel to the next without being able to penetrate the area under the roofing panel. In summary during the installation of a closed cut valley you install the first roof plane s shingles into the valley.

Roofing shingles are installed then cut and sealed where they overlap the metal channel. Unlikely but it can. Before lifting sheets on to the roof check that they are the correct way up and the overlapping side is towards the edge of the roof from which installation will start. Shingles in the valley will not last forever and will have to be replaces during a re roof project but the nails will not leak.

As a first line of defense against water damage it is important that the metal roof overlap be implemented correctly. He notes that due to the metal construction of an open valley it may shed ice and water more quickly which could help minimize granule loss. Overlap metal roof valley sections by 12 inches and seal the lap with a flexible sealant such as polyurethane or butyl on roofs shallower than 5 12. Install the roofing screws vertically along each rib in the panel.

Metal and timber compatibility. Low slope roofs slope less than 3 12 use tape sealant between the valley trim and the panel. Be sure the larger edge is laid so that the small edge of the next panel will overlap it.