Metal Roof On Treated Lumber

Until the copper content was raised in 2003 hardware with a g90 coating was acceptable for use with pt lumber.

Metal roof on treated lumber.

From rough dressed lumber to fence posts we guarantee to have the best quality and prices in the area. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. I do remember decades ago when us steel and kaiser aluminum were big metal panel roofing suppliers and aca cca which are salts treated wood was first commonly available they did recommend but not insist for warranty coverage that narrow strips of roofing felt be put across the top of the firring strips to avoid direct contact and possible corrosion. Experienced do it yourselfers can use a nail gun with 8d nail clips instead of a hammer and nails.

The pressure treated wood contains copper along with other metals that interacts with aluminum and causes the corrosion. Most pressure treated wood is treated with chromated copper arsenate. At max kendall lumber and tin we are the metal roofing manufacturer of master rib pbr and standing seam. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes.

To combat the corrosion caused by high copper content in the wood preservatives new galvanizing standards were established for the hardware manufacturers. The metal present in the treatment chemical copper is dissimilar to the metal roofing steel. For the roofing industry the potential for there to be corrosion related problems with the use of the current new generation of treated wood is a particular concern. Use a tool belt that has a hammer loop to hold nails a measuring tape chalk line and a hammer when installing the wood.

Most metal roof companies recommend installing felt paper on roof sheathing before you install the metal roofing. The asphalt in the felt paper is waterproof and does a great job of protecting the. By following a few simple steps the dissimilar materials can be separated and the corrosion process stopped. Step 1 determine the points of contact between the treated wood and the aluminum.

In roof assemblies treated wood is oftentimes used in as a component that interfaces with or is in direct contact with metal metal fasteners metal flashings and other metal accessories or metal roof decks. I would be concerned that galvanic corrosion could degrade the metal roofing or fasteners.