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Unistrut Interlock Plank Grating

Unistrut Interlock Plank Grating fills a variety of needs in a wide range of industries.  From flooring and rooftop walkways to mezzanines and stairway systems, United Interlock Grating Systems provide the durability you need with the ease of installation you expect with Unistrut products.  This post describes the features of Unistrut Grating and design considerations for your next grating project.

With all of the available choices, you may be wondering why we use United Interlock Grating during our field installations.  Interlock grating is light, making shipping economical and the planks interlock with positive friction, eliminating costly welding and bolting procedures.  During the typical installation, you’ll also require fewer support structures.  Ask any contractor what makes for an outstanding building material, and you’ll likely hear the same thing:  a variety of options to meet specific project applications.  This is where United Interlock Grating really shines!  With Unistrut grating, contractors can choose from:

  • 6” and 9” standard-duty sections
  • 12” light-duty widths
  • 1-1/2”, 2-1/2”, and 4” leg heights
  • Anti-skid, slotted-smooth punch surfaces, and solid unpunched grating sections
  • Double male and male-female leg shapes
  • Steel (6”, 9”, or 12”) and Aluminum Grating (6” or 9”)

 Best of all, Unistrut grating comes with a complete line of hold down clips, clamps, and washers to make short work of your installation:

nistrut Grating Clips and Clamps

Design Considerations

When planning and designing your grating project, remember to consider both uniform and concentrated loads. Design considerations are most critical when loads are concentrated on small areas. With larger applications, the reactions approach those of uniform loads. Although a grating section may take a considerable allowable load, deflection is always a consideration.  As a best practice, we suggest dividing the number of inches in the span length by 240 to yield a reasonable deflection rate.

point load example 

Point (Concentrated) Loads

We recommend distributing point loads over a minimum of two transverse ribs, regardless of plank grating size and gauge.  Good design practice for point loading plank grating utilizes a “foot” plate at the load point with a minimum dimension of 3" x 3". A foot plate will ensure the point load is distributed over the two transverse-rib minimum. Maximum point load per rib on 12" x 18 gauge steel plank grating is 185 lbs. With a 3" x 3" “foot” plate, a maximum design load for the minimum-dimension foot plate is 370 lbs. Higher loads can be supported by the transverse ribs, but larger “foot” plates are required to distribute the higher loads over additional ribs.

Selecting the Proper Grating

Floor areas adjacent to racks, shelves, and conveyors, as well as maintenance platforms, access ways and rooftop walkway applications are typically light-traffic areas suitable for 12" grating. Mezzanines and aisles for stock storage with high foot traffic require materials with higher fatigue strengths. For higher-traffic areas, we recommend narrow, high-strength 6" or mid-range 9" width grating.

Typical Unistrut Grating Applications

Unistrut Rooftop Walkway Standing Seam Roof

The railings and base framing of this 500’ rooftop walkway shown above are constructed using P1000, P1000T, P2346, and P1068.  To ensure a safe walking surface that can stand up to snow and ice build-up, we specified Unistrut Anti-Skid Grating (G11282, G12282 G9128) attached with G714 recessed washers and P3007 Channel Nuts.

Constructing a Unistrut rooftop walkwayOSHA Compliant catwalk made from Unistrut Grating

The photo above illustrates an OSHA compliant catwalk system fabricated from P1000, P1001, P5001, and United Interlock Grating.

Get Starting Building Your Project With Unistrut Grating Today

When it comes to mezzanines, catwalks, access platforms, stair systems, and rooftop walkways, the versatility of Unistrut framing channel paired with United Interlock Grating is second to none.  Thanks to the modular nature of the Unistrut System, your design can easily accommodate changes in elevation, rooftop obstructions such as drainage pipes and HVAC equipment, and more.  To learn more about Unistrut Grating, download our Unistrut Grating Brochure, or contact Unistrut Service Company for further assistance.