I am designing a masonry veneer wall with a steel-stud backup. I want to use stainless steel wall ties. How should I connect them to the galvanized steel studs? Should I use galvanized steel screws and washers to separate them from the steel studs?
The Brick Institute of America (BIA) recommends against using stainless steel screws with steel studs (see "Brick Veneer Steel Stud Panel Walls," Technical Notes 28B). John Slater of Invetech Inc., a Houston consulting firm that specializes in the behavior of metals in structures, feels differently. Most corrosion he has observed in wall ties attached to steel studs has occurred on the shank of the screw where it extends through the gypsum sheathing. Stainless steel screws would perform far better in this way than would galvanized steel screws. Because the stainless steel screws have far less surface area than the galvanized steel studs, they should induce little galvanic corrosion in the galvanized steel studs. If galvanic problems are still a concern, consider separating the stainless steel screws from the galvanized steel studs. For example, use a plastic insert in the studs to receive the screws. Or coat the screws with a plastic before installation. Although some of the plastic will strip away when the screw is installed, enough may remain to provide adequate separation. If creating a separation between screws and studs isn't satisfactory, consider attaching the wall ties to the steel studs mechanically without screws.