GALVALUME® wall panels provide a durable exterior to any building or residence. Calling them coated steel panels doesn’t do them justice. The material is much more than galvanized steel.
What is GALVALUME?
GALVALUME is a specific galvanized product made of 55% aluminum, 43.4% zinc alloy, and 1.6% silicon, a coating developed by Bethlehem Steel and licensed to all major steel manufacturers. The silicon encourages the adhesion of the aluminum and zinc to the steel substrate during the fabrication process.
GALVALUME is a brand name trademarked by Bethlehem Steel, but you can also find it under the names ZINCALUME, Galval, Cinclum, or Zintro-Alum. The companies licensed to produce and sell the product under Bethlehem Steel’s patents and technology include:
- ArcelorMittal Dofasco in Canada
- U.S. Steel
- Steel Dynamics
- AM/NS Calvert
How is GALVALUME made?
GALVALUME is produced through a hot-dip process in which coils of cold-rolled steel are welded end-to-end into a long strip. The uncoiled steel is cleaned of any rolling oils and mill dirt that could reduce surface oxides. Clean steel is more accepting of the coating.
The steel is continuously fed as a sheet into a molten coating batch sitting in an open-top, brick-lined heated pot. The production line whizzes along at speeds up to 600 feet per minute and continuously feeds the sheet into the molten coating bath. The sheet then passes around a roller in the bath and exits the bath vertically. As it exits, the steel pulls with it an envelope of coating material.
The steel and envelope pass through a pair of air knives that scrape excess coating material away to ensure the proper thickness. Typically, a feedback control adjusts the knife pressure and position in for uniform coating.
There are a few finishing steps, and the coated steel is re-coiled around a reel, ready for use.
Benefits of GALVALUME
The biggest benefit to GALVALUME outside of its durability is its reflectivity. GALVALUME panels can be pre-painted in the factory for a more durable color finish. A white finish, in particular, has significant reflective properties that can help keep the building cool in the summer and warm in the winter.
GALVALUME is particularly desirable when the panels must be cut or punched. The coating provides corrosion resistance even in these circumstances. Scratches are also less likely to corrode in a GALVALUME panel.
Just like its steel core, GALVALUME is easily formed and stamped or roll-formed into tiles, panels, and other architectural shapes. These panels as well as GALVALUME roof panels are light, strong, and won’t crack or peel during weathering.
GALVALUME insulation and flashing
Fiberglass insulation is the most common type used with this material. It can be any thickness needed to provide the required insulation value. A GALVALUME building envelope with appropriate insulation saves a significant amount of money on heating and cooling. The panels will last for decades as long as the insulation does not become wet.
Bare GALVALUME can be furnished with GALVALUME sheet flashing or aluminum flashing. We recommend against using galvanized flashing because it may not have as much corrosion resistance as the GALVALUME panels.
Do NOT place copper or lead flashing in direct contact with GALVALUME because this will galvanically corrode the aluminum-zinc alloy coating.
If you are using pre-painted GALVALUME, use pre-painted GALVALUME for the flashing as well. By using the same materials installed at the same time, you increase the chance that the colors are matched initially, and will weather uniformly.
What to avoid
There are a few materials that you shouldn’t bring into contact with GALVALUME. Two were mentioned earlier: copper and lead. Both metals can increase the speed and amount of corrosion in your metal wall panels.
You also do not want to install GALVALUME in direct contact with the roof decking. Wood soaks up water and holds it next to the GALVALUME panel, increasing corrosion activity. You can either place 30-pound felt or its equivalent between the decking and the panels or you can use roofing felt.
It is especially important to avoid situations where water can gather such as in warmer regions where condensation may occur between or under the panels. Cold regions threaten with snow, ice, and water that can collect under the eaves and other areas rather than drain away.
If insulation becomes wet, it can also encourage corrosion and mold. The walls can literally corrode from the inside out. Some flame retardant chemicals found in spray insulation can create corrosion as well.
Bare and pre-painted GALVALUME should not be in contact with concrete or mortar. Water can accumulate at crevices and encourage corrosion on the outer edge. Concrete is a highly alkaline material, which causes aluminum-zinc coatings to corrode rapidly. Damage can be caused by mortar splashes, tool, during masonry installation.
You can repair some of the damage by covering the affected area with a protective coating. Bare GALVALUME can be coated with asphalt based fiber aluminum finish coats such as Uniflex 500. Pre-painted GALVALUME can be repaired using the same coating as that used on the coil coating line. All surfaces must be clean and dry before you attempt to repair them.
Sill plates are required on concrete foundations to avoid contact and enhance drainage. The panel should not contact the sill plate. Instead, slightly tilt the sill plate away from the building to improve water drainage and aim it away from the wall.
If you insulate around the sill, take several inches of insulation off the vapor barrier near where the sill plate sits. Fold the vapor barrier up and around the insulation and then place it between the panel and sill plate.
GALVALUME is an incredibly durable coated steel product that can be used in its natural color or be pre-painted in any color you desire at the factory. It is a readily available material found at all major steel production and fabrication companies and is highly recommended for both roof and wall panels.
You can save on costs both initially and in the long-term by using GALVALUME, which requires little in the way of maintenance and when installed correctly, can last for 60 years or more. Further savings come from the energy efficiency you get from using light-colored or brightly finished GALVALUME.