Replacement floor gratings seems to be a must for alot of Atlas sites, especially
in the silo tunnel for some sites. Most sites have had the gratings salvaged to some
extent. Steel grating is in general easy to aquire either from Iron yards or purchasing
it from a distributer. Although the weight of steel grating being about 10lbs per
12" x 12" section makes it a back breaker to haul down to the silo entrance.

Recent technology has allowed the manufacturing of some grating ideas that
seem a bit more practical for replacing that old rusty grating with non rusting and
light weight options.

There are a ton of links on google for "Plastic Grating"
finding the closest manufacture or distributer in your area
might take a little of your time to find, but its well worth it.
Here are a few of the links that you might check out when
looking for Plastic Gratings.