Methods for Attaching Metal Roofs

Before Installing

• Before the metal roofing is installed, a solid plywood base must be in place and a breathable roofing underlayment material must be installed securely on top of the plywood. This allows moisture evaporation and prevents the wood from rotting. Flashing is installed over the roof underlayment materials at corners, gables and edges before the metal roofing is applied. Some metal roofing systems can be installed over asphalt shingles, but the condition of the roof must be evaluated before doing so.

Vertical Panels

• Vertical panels come in flat and interlocking styles that are secured with galvanized screws and washers. They can be purely practical or very decorative, with patterns and textures pressed into the metal. Vertical panels are laid flat from roof top to bottom edge, instead of horizontally across the length of the roof like common asphalt shingles.

Snap-Joint Assembly

• Metal roofing systems made in sections smaller than panels, such as shingles and tiles, snap onto fittings on tracks made for the roofing system. Lay tracks out on the roof area in horizontal rows starting near the bottom edge of the roof, screw them securely into the roof underlayment and snap the shingles or tiles into the track sections. Each row slightly overlays the row beneath it and the roof peak is covered with flashing.

Standing Seam Assembly

• Standing seam metal roof installation involves vertical panels connected with raised connectors at the seams, creating a ridged appearance. The raised connector pieces are clipped into raised edges of the vertical panels as well as screwed into the underlayment.

Important Installation Tips

• Avoid and eliminate any condensation issues with metal roofs by laying the metal roofing materials flat, on either existing shingles or the vapor barrier, so there is no air space underneath for condensation to form. Ensure there is adequate attic ventilation in all seasons. Be sure to follow the manufacturer’s instructions for spacing the screws for an attractive finished look and adequate security. Wear very thick leather gloves during metal roof installation to avoid painful cuts.