Gym floors are most usually concrete or screw-fixed plywood covered in a layer of ethylene propylene diene monomer rubber, which is better known by the acronym EPDM. This impact-absorbing material is considered a universal gym flooring because it is durable, hard-wearing, non-slip and easy to clean. It also looks good.
EPDM rubber is available as a series of large interlocking tiles, or on a roll. Most gyms use tiles. A popular brand is SPORTEC, with these (and similar) tiles distinguished by flecks which are a contrasting colour to the tile body.
Because EPDM offers good impact resistance, shock absorption and is useful in reducing sound and vibration, most gyms use it across the floor in varying thicknesses. However, you may come across a few other surfaces too.
Foam floors are installed for yoga, pilates and HIIT. They are made from polyurethane, which is softer than rubber with a perceptible bounce underfoot. Interlocking MotionFlex tiles from SPORTEC are one of the best examples of a high-quality foam flooring system. A lot of gyms use these for classes.
Running tracks are most often made from vulcanised rubber. The flooring is most often made from two layers of rubber; one soft, one rigid. The rigid rubber is the top layer to provide a stable base for the foot. The soft layer is the bottom layer, which exists to absorb energy and improve energy return.
Sled lanes and tracks
Sled lanes are most often made from needle-punched polypropylene. You can distinguish this material from others because it is akin to a felt. It is rough to touch, with the fibres acting as a smooth top layer for a sled to slide against. This material is often combined with a shock pad for plyometric exercises.
Impact protection slabs
You will find heavy-duty impact protection slabs next to power racks and deadlift zones. These are made from EPDM rubber. Some tiles in free weight areas are also impact protection slabs, even if they appear to be normal rubber tiles. 70mm tiles are used in most free weight areas to protect the substrate.
Where most gyms go wrong …
Plenty of gyms start out with a concrete or screw-fixed plywood floor covered in 20mm rubber tiles. 20mm is nowhere near enough for heavy weights. 30 to 40mm of rubber is the minimum a gym should be looking at, with impact protection slabs up to 80mm in thickness where necessary to protect the substrate.