Two People, Ninety Minutes: Crewing a Snow Build Properly

One mixer, two people, and a hundred and twenty square metres at 40 mm. That combination takes about ninety minutes from first bag to groomed floor, provided the water is where it should be and the barrow route is clear. Put four people on the same job and it takes two hours, because two of them are standing waiting for a tub that is not ready and the fourth is carrying bags across a floor that the second is trying to lay.

Snow builds have a throughput problem that looks like a staffing problem. Adding people to a line that is already waiting does not shorten it; it adds coordination and boots on the fresh surface. The arithmetic below is worth doing before the crew call goes out, because it is the difference between a calm build and a rushed one.

The Throughput Numbers

A single paddle mixer in a 200 litre tub will turn out roughly 40 kg of dry powder per batch, which becomes about 240 kg of wet snow, in 25 to 30 minutes including the rest. That is 480 kg of wet material an hour at best, and 350 in practice once you allow for filling, tipping and the occasional lump.

At 0.45 kg per litre, a 40 mm layer weighs 18 kg per square metre. So one mixer sustains about 20 to 25 square metres per hour of laid floor, and the whole hundred and twenty takes five to six hours of mixing. That number is the one that decides the schedule, and it is usually double what the production assumes.

The Three Roles That Actually Matter

Mixing is a full-time job and should not be combined with laying. The mixer’s attention is on water addition rate and rest time, and a person who leaves the tub to help carry a barrow comes back to a batch that has set unevenly.

Laying is the second role: tipping, spreading to depth, and rough-levelling with a screed board or a length of timber. This is the job that sets the density, because a layer that is dumped in one place and spread outward compacts at the centre.

Grooming is the third, and it is the one most often skipped. A soft brush or a leaf rake, used lightly over the finished surface, opens the top few millimetres and removes the sheen that spreading leaves behind. Without it, the floor looks pressed rather than fallen.

Where the Bottleneck Really Sits

Almost never at the mixer. On most indoor jobs the constraint is the distance between the mixing station and the set, and the width of the route. A 60 metre carry with a barrow, through two doors and around a corner, costs four minutes each way. Ten trips is forty minutes of one person’s day, and that person is usually the one who should be grooming.

Fix the route before you fix the crew. Put the mixing station as close to the set as water and drainage allow, protect the floor along the carry, and use two barrows so one is always loaded. If the venue will not let you mix near the set, budget for a third person purely on transport and accept that the build will take longer than the arithmetic suggests.

One failure worth remembering: a crew of six was booked for a lobby build, and the floor came out patchy because four of them were laying at once from different tubs, each at a slightly different density. The joins were visible under the downlights. Two experienced people and a clean route would have produced a better floor in the same time.

Write the throughput figure on the call sheet next to the crew names, and calculate the mixing hours before you agree the build window. The snow powder supply absorbs consistently enough that the 40 kg batch figure holds across grades, which makes the planning arithmetic reliable.