Home > Products > Insulated Sandwich Panel Roofing & Wall Insulated Sandwich Panel Roofing & Wall Bi-metallic self-drilling screws over 100 mm for fixing insulated sandwich panels on roof and wall, with sealing washers that protect the panel core. RUSPERT coated to Class 4 (AS 3566.2-2005). Hex Small Flange Bi-Metallic Structural Screw 20 x 8″Add To InquiryView details → Hex Small Flange Bi-Metallic Structural Screw 14 x 6″Add To InquiryView details →