Interstate Grating Products

Steel Bar Grating

Steel Bar Grating is manufactured from ASTM A-1011 mild carbon steel and is available in three distinct products, type "W" Welded Bar Grating, type "DT" Dovetail Pressure Locked Grating, and type "SL" Swage Locked Grating. All three products are available with bearing bar spacing ranging from 19/16" (1-3/16") to 7/16" on center and with cross bars at either 4" or 2" on center. Each product is available with the standard plain or optional serrated surface, and each product is available with a bare steel, painted or galvanized finish. The following Steel Load Tables provide detailed product specification information related to all three products.

Type "W" Welded Steel Grating

Our most economical steel grating products, type "W" Welded Steel Gratings are manufactured by forge welding rectangular bearing bars and drawn cross bars. This welding process provides a positive fused connection providing years of service under the most demanding conditions. Type 19-W-4 steel grating is our most popular product and is recommended for nearly all industrial flooring applications. With nearly 80% open area, 19-W-4 allows for the easy passage of dirt, debris, snow and liquids and is essentially self-cleaning. Type "W" gratings are available in close mesh ADA conforming spacings 11-W-4 and 7-W-4 which are commonly used in public areas. When specifying type 11-W-4 for ADA applications, 3/16” thick bearing bars must be specified.

Type "DT" Dovetail Pressure Locked Steel Grating

Type "DT" steel gratings have deep rectangular cross bars and are manufactured by inserting pre-punched bearing bars and cross bars into an “eggcrate” configuration and deforming the cross bars under intense hydraulic pressure. The deep cross bars on type "DT" gratings make them popular for architectural applications such as sun shades and infill panels with the deeper cross bar serving as a distinct architectural accent.

Dovetail Intersection

Type W

Type "SL" Swage Locked Steel Grating

Type "SL" steel gratings are manufactured by inserting hollow tube cross bars into pre-punched holes in the bearing bars and swaging the cross bars forming a positive mechanical connection. The cross bars are recessed below the top surface of the bearing bars providing a uniform and attractive architectural appearance. Swage locking is a particularly efficient process for the production of close mesh gratings. Type 7-SL-4 with 3/16" thick bearing bars provides a net 1/4" clear opening between the bearing bars. This narrow opening is often preferred in public areas where concerns of drainage and the presence of high heeled shoes converge.

Swaged Intersection