Interstate Grating Products

Product Specification

Service Loads

The load tables on the pages within this website provide load/deflection criteria for most common applications. These tables provide a concise reference allowing the specifying authority to select the appropriate bearing bar size and spacing for the intended application. Pedestrian loads are commonly analyzed with uniform and concentrated loads. For pedestrian comfort, deflection is typically limited to 1/4". Heavy duty and vehicular load tables are presented for specific load conditions. Heavy duty load tables are presented with deflection limited to the lesser of 1/8" or L/400. If your application is not addressed by the load tables found in this website, please contact Interstate Gratings. We will gladly discuss the merits of our diverse products and assist in selecting the product most appropriate for your application.


Load / Deflection Criteria

When specifying metal bar grating it is important to consider the following factors:

  • Service load required and acceptable deflection
  • Unsupported clear span
  • Flooring surface
  • Banding and trim
  • Finish



The open ends of the grating panels can be banded to provide additional transverse stiffness and a finished architectural appearance. This is achieved by welding a flat bar, similar in size to the bearing bars, to the cut ends of the grating. Trim banding should always be specified when gratings are designed to be removable. Banding can reduce impact stresses by transferring loads to adjacent bearing bars and should always be specified when the grating is subject to vehicular loads. Further banding descriptions and details can be found under Banding/Layout/Fasteners.

Serrated Surface

The excellent self-cleaning characteristics of plain surface grating make it suitable for the majority of applications. In the presence of fluids or materials that could cause the top surface of the grating to become wet or slippery, specification of the optional serrated surface should be considered. When serrated grating is specified, the bearing bar depth must be 1/4" greater than the sizes shown on the load tables to provide the equivalent strength of non-serrated gratings..



Steel grating is usually provided with one of three finishes, bare steel (no finish), painted with one coat of manufacturers red, black or silver paint, or hot dip galvanized in accordance with ASTM A-123. Aluminum products are commonly supplied mill finish but they are also available with optional chemically cleaned or anodized finishes. Due to discoloration that occurs during welding and fabrication, Stainless Steel grating products typically require secondary finishing



Commercial cleaning, passivation or abrasive blasting can provide a uniform matte surface and a bright stainless finish can be provided by electro-polishing. All grating products can be provided with specialty finishes including enamel or epoxy paints or powder coating. When considering specialty finishes, consultation with the coating manufacturer is essential.

Painted Steel Mill Finished & Anodized Aluminium Galvanized Steel Commercial Clean Stainless Steel Powder Coated Steel