Preparing the Site Before a Walk-In Is Installed

By Renato J. Alonso, Founder and President, Qube Cold Storage Solutions · Updated October 28, 2026

Have six things ready before the truck comes: a level, finished concrete floor; power roughed in at the right voltage and phase; a drain route for each evaporator; a spot for the condensing unit; enough clear height; and a path for long panels to reach the room. A freezer without its own insulated floor needs concrete designed for it, and that is the one item you can't fix after the fact.

The checklist

Item	What ready means	Who usually does it
Floor	Level, flat, finished concrete under the whole footprint; any recess for a flush floor already poured	General contractor
Power	Circuits for each condensing unit, each evaporator, and the door heaters and light, at the voltage and phase on the submittal	Electrician
Drain	A route from each evaporator to an approved drain; heat on freezer drain lines	Plumber or refrigeration contractor
Condensing unit location	Roof curb, wall bracket or ground pad, with airflow around it and a reasonable line-set run (the refrigerant piping) to the box	Refrigeration contractor
Clear height	The box height plus working room above it to set the ceiling panels, and more for top-mount units	You, with your installer
Path in	Doors, halls and turns wide enough for panels as long as the room is wide	You
Permits	Building, electrical and mechanical, as your jurisdiction requires	Owner or contractor

For the voltage and phase details, see walk-in electrical requirements. For height and the path in, see how to measure for a walk-in.

Floors: the item that can't wait

• Floorless coolers sit directly on your concrete and are sealed at the base. If the floor is out of level, it shows up at the door: it drags, or it won't seal.
• Recessed (flush) floors need the depression in the concrete poured before delivery, so carts roll in level. A common recess is about 5".
• Freezers ship with a 4" insulated floor as standard. A floorless freezer is only right on concrete built for it: insulation under it, a vapor barrier, and protection against the ground freezing and heaving. That is engineering by others, done before the concrete is poured. See does a walk-in need a floor.

Condensing unit location

• Outdoors on a pad or on the roof is most common. The unit needs open air around it to get rid of heat.
• Tell us the distance from the unit to the box. Long line-set runs can change the selection, and some project specs set a maximum, such as 100 feet.
• In hot climates, avoid a spot that traps heat, like a wall corner in full afternoon sun. See indoor vs outdoor walk-ins.

Drains

Each evaporator drains condensate. On a freezer, the drain line needs a heater along its full length, or it freezes shut. The standard 6' drain-line heater is often too short for the actual run, so measure the run and tell us.

Clearances

Your installer, the refrigeration equipment instructions and local code set the clearances around the box and the condensing unit. Tell us what your installer needs and we draw the box to fit.

From the field

We were asked to match another quote on an 8' x 12' freezer at −10°F, floorless, set on concrete with no insulation designed under it. The other quote's evaporator coil looked about 20% short of the box load we calculated. We would not match it, for two reasons. A freezer on uninsulated concrete freezes the ground under it, and frozen ground heaves the floor and the walls with it. And a coil that small would run nonstop and still not hold −10°F on a busy day. We quoted the freezer with its own insulated floor and refrigeration sized to the load. If you want a floorless freezer, design the concrete for it first, and size the refrigeration to the floor you actually have.

Questions people ask

Can a cooler go on a wood floor?

Order it with an insulated floor. Floorless boxes need concrete.

Does the room need air conditioning?

No, but the condensing unit's location and the temperature around the box both affect the refrigeration selection. Tell us if the box sits in a hot, unconditioned space.

Who installs the box?

Installation is by others unless included in writing. Our drawings and submittals give your installer what they need.