A flatted factory unit is where a great many Singapore businesses actually keep their stock. Not a purpose-built warehouse with a roller shutter onto a yard — a unit on the fourth floor of a multi-storey industrial building, reached through a lift lobby and a common corridor.

Racking one of those is a genuinely different exercise. The design is not decided by how much stock you have. It is decided by three constraints the building imposes on you before anyone draws anything: what fits in the lift, what the floor is rated for, and what the ceiling actually leaves you.

Get those three established first and the layout follows quickly. Skip them and you get a delivery that cannot come up, or a system that has to be derated after it is built.

1. The goods lift decides your component lengths

This is the constraint people find out about last and it is usually the one that governs everything.

Racking arrives as long components. Uprights are the long ones — a frame tall enough to be worth building is longer than most goods lifts are deep or tall. Beams are long too. If the lift will not take them, they do not reach your unit, and no amount of good design on paper changes that.

So before a layout is drawn, measure the lift properly:

• Internal car dimensions — width, depth and, critically, height to the underside of the car ceiling. A long component can sometimes go in diagonally, which is why the diagonal matters as much as any single dimension.
• Door opening, which is often smaller than the car itself.
• Rated capacity, because a bundle of steel uprights is heavy.
• Whether there is a hatch in the car roof, which some goods lifts have and which occasionally rescues a long item.

Then measure the route on both ends: the lift lobby, the corridor, any turn, and the door into your unit. A component that fits the lift but cannot turn the corner outside it has not arrived.

What this changes in the design: it pushes you towards shorter uprights, sometimes spliced on site to reach the height you want, and towards systems built from shorter members. It is a normal thing to design around. It is only a problem when it is discovered on delivery day.

2. Floor loading is a different number upstairs

On a ground-floor warehouse slab, floor loading is rarely what limits you. On an upper floor of a flatted factory, it very often is.

Upper floors are suspended structure with a stated loading limit, and that limit is usually far below what a ground slab will take. It should be in your lease or available from the landlord or building management. Get it in writing, and get it for your floor and your area, because it is not necessarily uniform across a building.

Two things matter beyond the headline figure:

Point loads under baseplates. A rack does not spread its weight evenly over the floor. It concentrates it at each upright, into a baseplate the size of your hand. A layout can be well within the average allowance per square metre and still be too concentrated at the feet. This is why the loading conversation belongs at design stage, not after installation.

Where you put the heavy stock. On an upper floor, the answer is often not "wherever it fits". Concentrating your densest pallets in one bay of one aisle is exactly the pattern the floor likes least.

The lease side of this is covered in more depth in racking in a leased warehouse, and it is worth reading before you sign anything, because the floor loading figure and the reinstatement clause are both negotiated at that moment and never afterwards.

3. The ceiling is lower than you think, and not flat

Flatted factory units generally have less clear height than a purpose-built warehouse, and what height there is gets eaten from the top down.

What eats it: structural beams, sprinkler pipes and heads, lighting, ductwork, cable trays, and the fire services generally. Your usable height is not the slab soffit — it is the underside of the lowest thing over each part of the floor, and that varies across the unit.

Measure it per area rather than taking one number for the whole space, and record where the low points are. It is common for one half of a unit to take an extra beam level and the other half not to, and that is a perfectly good design once you know it.

Sprinkler clearance is a rule rather than a preference, and it applies to the top of your stored goods, not the top of your steel — sprinkler clearance and racking approval covers what that means in practice. There is more on measuring usable height in clear height and how many beam levels you actually get.

The column grid and the door

Flatted factory units tend to be column-heavy, and the columns are where they are. Racking runs want to be long and straight; columns interrupt them. The usual answer is to set the run direction by the column line rather than by the shape of the room, absorbing columns into the ends of runs or into cross-aisles instead of leaving them stranded mid-aisle. That is its own subject — see working around columns and obstructions.

The door matters too, and it constrains handling rather than delivery. Most upper-floor units are worked with a hand pallet truck or a walkie stacker rather than a counterbalance forklift, because a counterbalance machine is heavy, and getting it up there is its own problem. That changes aisle widths, and it changes how high you can practically place a pallet.

What tends to work in these units

None of the above rules out proper racking. It shapes what kind:

• Boltless or long-span shelving for hand-picked cartons and lighter stock. It comes in shorter components, goes up the lift without argument, assembles without tools, and suits a unit where most goods move by hand. If your stock is boxes rather than pallets, this is usually the right answer regardless of the building — see boltless shelving versus pallet racking.
• Selective racking at a modest height, built from uprights short enough to reach the unit, where you genuinely handle pallets.
• A mix, which is what most units end up with: pallet positions along one wall for bulk, hand-pick shelving through the middle.

What tends not to work is a system chosen from a catalogue on the basis of capacity alone, without anyone having measured the lift.

Before you sign the lease

If you are still choosing the unit, these are the questions that decide whether it will suit you, and they cost nothing to ask:

• What is the floor loading limit for this floor, in writing?
• What are the goods lift's internal dimensions, door opening and rated capacity?
• What is the clear height to the lowest obstruction — not to the slab?
• Where are the columns, and is there a dimensioned plan rather than a marketing one?
• Is the unit sprinklered, and what does that require of the storage height?
• What does the reinstatement clause require, and does it cover anchor holes in the floor?
• Are there restrictions on working hours or lift booking for a fit-out?

That last one is not trivial. Installing racking in a flatted factory usually means booking the goods lift, which usually means evenings or a weekend, which changes the programme and the cost.

The short version

Racking an upper-floor unit is a design constrained by the building rather than by the stock. Measure the lift and the route to the door, get the floor loading in writing for your floor, and measure the clear height to the lowest obstruction across the unit rather than taking one number.

Do that first and everything else — run direction, beam levels, which system — falls out of it sensibly. And anchoring into an upper-floor slab has its own considerations, covered in anchoring racking to the floor.

Fitting out a flatted factory unit? WhatsApp us on 9107 2601 — tell us the floor, the goods lift dimensions, the floor loading figure if you have it, and what you are storing, and we will tell you what will physically fit before anything is quoted. More on the systems themselves on our racking page.