Pictured above: V3000 racking from our project archive, an ambient unit. The frame family is the same one that ends up in a chiller or freezer once it is converted — what almost never survives the move unchanged is the finish, and often not the racking either. That is what this article is about.

Many cold room projects are not a blank warehouse being fitted out from scratch. They are an existing unit — often with racking already standing in it — that a tenant wants to turn into a chiller or freezer because the business has changed: a new client wants cold-chain storage, a lease renewal is a chance to add capacity, or an ambient bay next to an existing cold room is being annexed to it.

The design questions for cold storage racking itself are covered in cold room and chiller racking: what actually changes. This article is about the conversion project specifically — what happens to the racking, the goods, and the operation while an ambient space becomes a cold one.

The racking that is already there usually cannot just stay

The instinct is to keep the existing racking and simply change the room around it. It is understandable — the steel looks fine, it is carrying the same pallets it always has — but the frame was very likely specified for a dry, ambient environment: standard powder coat, base plates and fixings chosen for a normal warehouse slab, no allowance for constant condensation or sub-zero cycling.

Put that frame in a wet chiller and the finish is doing a job nobody chose it for. Corrosion starts at cut edges, welds and any point where a pallet has already chipped the coating, and it does not announce itself until the frame has been in there for a while. Put it in a freezer and the concern shifts to what the slab underneath is doing, because a freezer floor is a different build-up to the one that frame was anchored into.

So the honest starting point on a conversion is an inspection of what is already standing: the finish, the fixing detail, and the general condition of the steel. Sometimes it genuinely is reusable — a frame that is only lightly loaded, going into a mild chiller, with a finish upgrade applied before it goes back in. More often, at least the components nearest the floor and the worst-corroded bays need replacing, and it is cheaper to know that before the room is sealed up than after.

Reuse, relocate, or replace — three different answers, not one

"Keep the racking" is not actually one option. Once the frame has been inspected, it usually sorts into three separate answers, and a single unit can have all three at once.

Some bays are genuinely fine to reuse as they stand, most often the upper levels that see less pallet contact and less exposure at the floor. Some bays are structurally sound but wearing the wrong finish for what the room is about to become, and those go back in after re-coating or a component swap rather than a full rebuild. And some bays — typically the bottom metre, where forklift impact and floor-level moisture concentrate — have taken enough damage over their working life that it makes no sense to carry them into an environment that will be far less forgiving of a weak point.

What we will not do is call a level "probably fine" from a walk-through and sign off on reusing it. That decision made from a distance is exactly how a warehouse ends up two years into cold storage with a bay that has to be pulled and replaced with product already sitting on it — which costs far more than the inspection would have.

Sequencing: the part a design drawing does not show

A conversion project has a constraint a new-build does not: there is usually stock in the space, and the operation often cannot stop for the whole job.

The practical sequence we work to is to clear and stage goods out of the section being worked on first, strip and inspect the existing racking bay by bay rather than all at once, and only commit to what gets reused once each bay has actually been assessed rather than judged from a walk-through. Where the room has to keep functioning, the racking work is staged section by section, the same way we stage installation inside a working cold store once it is at temperature — described in the article linked above.

The refrigeration side adds its own sequence on top: bringing a converted room down to temperature involves a pull-down period, and if the room has ever been warmed for building work there is a dry-out to go through before it is trusted again. Those steps belong on the programme from day one, not discovered once the racking crew turns up and the room is not ready for them.

For a standard ambient racking job, survey to handover typically runs four to six weeks: about a week for layout and structural sign-off, two to three for fabrication in our Singapore workshop, and one to two for installation. A conversion adds the refrigeration sequencing and the staged, section-by-section install on top of that ambient baseline — how much it adds depends on the room and the mechanical works, which is exactly why we scope it at survey rather than quote a number before seeing it.

The floor drawing you need before anything is designed

Freezer floors in particular are built up with insulation and, in many installations, a sub-slab heating arrangement to stop the ground beneath from freezing and heaving over years of use. If the unit already has that build-up from a previous cold room use, anchoring new or existing racking into it without the drawing in front of you is a real risk to the floor, the frost-protection system and any warranty attached to either.

If the unit has never been a cold room before, the reverse question applies: what is in the existing slab now, and what does the conversion do to it. Either way, the drawing comes before the layout, not after.

Airflow and decking, carried over from the design article

One design point is worth repeating here because it interacts directly with reused racking: a cold room cools by moving air, and a layout that packs reused bays in tightly without leaving the evaporator's throw path clear can create dead zones several degrees off the rest of the room. If the existing layout was designed for an ambient aisle pattern, it is worth re-checking against the airflow path rather than assumed to carry over unchanged. Mesh decking is generally preferable to solid boards in a cold room for the same airflow reason, and existing solid-decked bays are one of the more common things that get swapped out during a conversion even when the frame itself is kept. The full reasoning is in the design article linked above.

What we check before we quote a conversion

• What racking is already there — system, finish, fixing detail, and condition, assessed rather than assumed.
• Whether the unit has ever been a cold room before, and if so, what the floor build-up actually is.
• Chiller or freezer, and the target temperature and humidity regime, since the two are opposite problems for both the steel and the floor.
• Whether the operation needs to keep running during the works, and which sections can be taken out of service first.
• What is stored on the racking now, and where it goes while its bay is being converted.

Converting an existing bay into a chiller or freezer and want to know what it means for the racking that is already there? WhatsApp us on 9107 2601 and we will start with an inspection of what is already standing before anything is drawn. Our systems are on the pallet racking systems page and the full scope is on services.

Related reading: cold room and chiller racking: what actually changes · drive-in pallet racks Singapore · racking project timeline: survey to handover