Where a tough, hard wearing deck is required, especially where heavy machinery, pallets of material, engine blocks, scrap metal or similar is dragged, pushed, slid or driven onto the trailer, a steel deck is a good choice.
Steel decking can be either flat plate or with the raised tread plate design similar to the aluminum decking or open mesh (see below).
Steel has a natural tendency to bounce back to its original state if abused and is easy to repair if anything major is required.
1/8" steel plate is really the ideal thickness you want and this will cope with just about anything you can throw at it. A flat sheet of 1/8" steel, 4' x 8', weighs approximately 154 lbs with a 1/8" tread plate sheet the same size, coming in at 165 lbs. For comparison, a 1/4" aluminum sheet comes in at around 116 lbs.
One advantage with steel is the relative ease in getting sheets cut to the correct size for your trailer.
Steel decking can be welded, coach bolted or screwed to the chassis. If the trailer is to be welded, particularly if the trailer is to be galvanized, care needs to be taken to ensure that welding stresses are not put into the chassis as these may cause the chassis to twist and distort when heated in the galvanizing bath. Welded steel deck trailers that have been galvanized tend to expand between cross members and have a skeletal look to them.
Pre-drilling steel decks and galvanizing the trailer and deck separately normally have a better result in both looks and a straightness of the chassis. 1/8" steel can be purchased already hot dip galvanized and may be the best option if bolting/screwing the deck to the trailer.
Fitting a galvanized deck on a painted trailer looks smart and gives the deck and trailer a considerably longer life.
Flat steel decks can be very slippery when wet and even tread plate decks can be a hazard.
Open mesh decking is also available and can be supplied either, drilled, perforated, woven or expanded metal and each has their own characteristics regarding strength and versatility. Woven, perforated and expanded mesh decks are great for preventing slipping and are suitable for transporting small animals or light machinery like ride on lawn mowers/tractors or similar sized machinery where ease of cleaning is required.