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Flat-Lock Copper Fails Prematurely

In this example of a copper sheet metal valley, we’re going to review a couple critical mistakes made during the installation and what steps should be taken to avoid premature failure of copper sheet metal.

To begin, the maximum size allowable for flat-lock soldered copper panels is 18″ x 24″. Attached below is a picture to show a properly sized copper flat-lock panel. The reason for the smaller panel is because copper expands and contracts significantly more than galvanized steel, for example. The copper flat-lock panels are secured to the roof individually so they must be kept relatively small (18″ x 24″ max.) to limit the movement and stress placed on the soldered seams.

The second design flaw is the lack of an expansion joint. Expansion joints must be incorporated to allow for movement during changes in temperature. In Cincinnati, Ohio, its possible to experience 60-70 degree temperature swings in just 24 hours. Without expansion joints the copper will destroy itself. Typically, the soldered seams will crack first and over time the copper will develop splits and cracks due to constant movement back and forth along the panel. Below is an example of a properly installed expansion joint in a copper built-in gutter, installed by HKC Roofing.

Copper is a beautiful and long lasting material when properly installed. It’s also a very expensive material, so it’s important to ensure your contractor understands all the nuances involved when working with it. Unfortunately, the copper work reviewed in this video will need to be removed and completely replaced.