How to Install a Metal Roof With an Air Gap

Cover your plywood roof deck with tar paper or building felt and staple it in place.

Lay 1-by-4 beams across the width of the roof deck, with one row every 24 inches up the length of the roof. Mount them in place with one screw spaced every 4 feet. These beams will serve to elevate the roofing panels and create the air gap.

Screw the eave trim to both the lowest 1-by-4 and the edge of the roof deck every 24 inches. Overlap pieces of trim by 4 inches. Glue a foam inside closure strip along the length of the lowest beam to seal the gaps created by the panel crimps.

Lay the first roofing panel, with crimps running from ridge to eaves, in the lower downwind corner of the roof. Screw the roofing panel to each 1-by-4 beam in the flat of the panel next to each crimp with washered wood screws. Lay the next panel just above the first one, overlap it by 6 inches and secure it the same way. Continue upward until you reach the ridge.

Apply a strip of butyl tape along the inside edgemost crimp of the first column of panels, attach the lowest panel of the next column to it and overlap the edge crimps. Install subsequent panels in the column the same way as the first panel and continue, one column at a time, until the panels reach the upwind edge of the roof.

Finish the installation by screwing the gable and ridge trim into place. Place a strip of butyl tape under the gable trim and foam outside closure strips under the ridge trim to seal any gaps.