How an ice rink works: freezing, resurfacing and the Zamboni

An indoor ice rink is a giant, carefully managed freezer. Here is what is under your skates, how the ice is built and painted, and why that machine comes out between every session.

What is under the ice

A permanent rink sits on a concrete slab with a grid of pipes running through it. A refrigeration plant pumps a chilled liquid (usually brine or glycol, cooled by ammonia or another refrigerant in the plant room) through the pipes, which keeps the slab well below freezing. Under the slab there is insulation and, on most rinks, a heated layer to stop the ground beneath from freezing and heaving.

Building the ice

The ice itself is surprisingly thin, typically only a few centimetres. It is built up by spraying fine layers of water onto the frozen slab, one at a time, so each freezes quickly and evenly. After the first thin layers, the ice is painted white, and then the hockey markings and logos go on: the red centre line, the two blue lines, the circles and the goal creases. More layers seal the paint in.

Keeping it right

Different users want different ice. Figure skaters like it slightly softer and warmer so the blade edges grip for jumps and landings; hockey players like it harder and faster. Rinks adjust the slab temperature between sessions, and the air in the building is kept cool and dry so the surface does not get soft or foggy.

The resurfacer (the "Zamboni")

Every session leaves the ice scratched, snowy and rutted. The ice resurfacer, often called a Zamboni after the American inventor Frank Zamboni, whose company made the first one in 1949, fixes that in a single pass:

1. A sharp blade underneath shaves a thin layer off the top of the ice.
2. An auger collects the shavings ("snow") into a tank.
3. Water washes the surface, and the dirty water is vacuumed back up.
4. A cloth towel at the back lays a thin film of warm water, which freezes smooth within minutes.

That is why public sessions end with everyone off the ice, and why hockey games pause between periods.

Outdoor and home rinks

Temporary outdoor rinks use the same principle with mats of pipes laid on the ground, and they struggle on mild, sunny or rainy days. Backyard rinks in cold countries simply flood a frame with water when the air is below freezing, something British winters rarely allow for long.

For the story of Romford's own rinks, see Romford Ice Arena and Sapphire Ice & Leisure.