How to Install a Nailless Metal Roof

Install a breathable roof underlayment using roofing nails, according to manufacturer's specifications. The underlayment protects the decking below your metal roof. Attach a radiant barrier above the underlayment if your local conditions demand one, this helps to slow heat penetration from the roof into the attic.

Install drip edge on the eaves by pushing the metal pieces flush with the roof decking, over the underlayment. Screw through the drip edge at 8- to 12-inch intervals, staggering the screws so the drip edge fits tightly to the decking. Overlap sections by at least 2 inches, opening the lip of the overlapping piece for a more snug fit. Make any cuts using metal snips. Drip edge should be applied to gable ends if a more complicated trim package is not desired.

Fold the bottom 7/8 inch of the first panel under, creating a hook lock. Bend 7/8 inch along the long edge of the first piece at a 90-degree angle for an installation into drip edge (follow manufacturer's guidelines for trim packages). Lift the panel into place on the roof, engaging the locks into the drip edges.

Install the first clip 10 to 12 inches off of the bottom drip edge by clipping it over the standing seam and screwing the clip into the roof decking with flat top screws. Repeat every 10 to 12 inches, until you approach the end of the panel. If the roof is longer than the panels, bend a hook lock into the long edge of the next panel and hook it over the side drip edge. Overlap the first panel with the new one by 2 inches and continue with the installation. Install each run of panels 2 to 3 inches short of the roof peak.

Create a hook lock on the bottom of the first panel of the second run (but not on the long side), and slide it carefully into place, making sure to overlap the standing seams. Push the panel carefully into place and use the hand seamers to crimp the roofing pieces together. Install panels and clips using the method described in Step 3. Repeat panel installation across the roof.

Cut the last row of panels on the ground and bend a 7/8-inch hook lock along the long edge that corresponds with the gable drip edge before installing these panels on the roof. Measure and cut carefully, since there is no guarantee that the roof is completely square.

Install the metal peak using Z-bars designed to work with your ridge cap. Cut the Z-bars 1/4 inch shorter than the width of the roof panels. Cut a short piece of ridge cap to use for spacing. Screw down the Z-bars with the locking lip facing away from the peak, using the ridge cap piece to space them properly. Caulk the connection between the roof panel and Z-bar on the peak side. Caulk the side gaps.

Cut a 2-inch line down the center of the first piece of ridge cap and remove 2 inches of the lock. Bend the flaps down to create an overlap for the end of the ridge. Hook the ridge cap into the Z-bars and crimp them in place with the hand crimper. Screw the overlap into place. Remove 3 inches of the lock from the next piece of ridge. Apply two lines of caulk where the ridge pieces overlap and place the new section on top of the old. Crimp the new piece in place. Repeat to the end, finishing with a piece cut down the center and folded like the first.