12.7. Horizontal Flat Lock Systems

Description: This type of wall panel is basically identical to flat seam roofing applied on a vertical surface. However, neither solder nor sealant is required in the joints, since the vertical surface provides positive drainage.

The panels are typically 18 x 24 inches, with 3/4 inch folds on all four sides. Two sides are folded over and two folded under. All corners are trimmed at a 45 degree angle.

The single lock seams are typically hammered flat. The minimum recommended gauge is 16 ounce copper.

Cleats are fastened with two stainless steel screws per cleat.

Substrate: Continuous nailable substrate.

Fastening Method: Cleats screwed to substrate.

12.7A. Typical Section

This section shows the single lock seam and cleats used for both horizontal and vertical joints.

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12.7B. Typical Axonometric

This detail shows that one side and the lower edge of each panel lock into adjacent panels. The other side and upper edge are held by two cleats each. Vertical joints are always staggered for weather resistance.

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12.7C. Typical Copper Panel

These elevations show the typical panel, before and after the edges are folded.

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12.7D. Typical Window Head and Sill

Wood blocking can be used at the head as shown. It provides a solid surface for attaching the copper head flashing and continuity around the window opening. The lower edge of the copper wall panels is locked into the head flashing to provide a drip.

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At the sill, the wood blocking is covered with copper sill flashing which is locked into the upper edge of the copper wall panels. The ends of the sill flashing must be dammed to prevent water leaks into the wall cavity. If aluminum or other metal window frames are used, a bituminous coating or other isolating material must be applied to the sill flashing to prevent direct metal-to-metal contact.

For corner and base details, refer to Wall Cladding Systems - Diagonal Flat Lock Panels.