Guides / Container Buildings
A portable site office container has no catalogue price, because it is quoted per unit against a scope rather than per square metre, and the same 20 ft shell can be quoted with the internal fit-out, the electrical package, the air conditioning and the delivery either inside the number or left out of it. The price is the sum of four lines — shell, fit-out, services, and transport with lifting — so a figure can only be judged once you know which of the four it covers.
Ask for a unit rate against a scope, not a price per square metre. Site offices are bought as whole rooms: a fixed steel frame, walls and roof, a floor, a door, windows, and whatever wiring and lining the order specifies. Two suppliers can quote the same nominal size and be working on different products, one a bare shell and the other a finished office with a partition, a split-unit air conditioner and a distribution board.
The practical answer to “how much does one cost?” is therefore: the number is only meaningful next to the four lines below, and the fastest way to a comparable figure is to send the unit count, the layout and the services in one message.
The table below is the structure most quotations follow once they are itemised. It is not a price list; it is the list of things to check that a quote has priced.
| Line | What sits in it | What moves the number |
|---|---|---|
| 1. Shell | Frame, corner castings, wall and roof panels, floor deck, door, windows, surface finish | Wall and roof build-up, steel section size, whether the unit is designed to be lifted again, paint or powder finish |
| 2. Fit-out | Insulation, internal lining, floor covering, ceiling, partition walls, worktops, sanitary pod | Number of rooms, whether the partition reaches the ceiling, whether a toilet and wash basin are built in |
| 3. Services | Distribution board, cabling, sockets, lighting, switches, air conditioning, water heater | Connected load, heating or cooling capacity, number of circuits, whether the supply is single or three phase |
| 4. Transport and lifting | Inland haulage, ocean freight, port charges, lifting or offloading at destination | Destination, number of units per shipment, whether a crane or a forklift is available on arrival |
Line 4 is the one that most often sits outside a unit price. A quotation that names a destination and an incoterm can be compared; one that gives a unit figure alone cannot, because the freight is still to come.
Most site office units follow the ISO series 1 container footprint so they can travel on standard equipment and be lifted by the corner castings. ISO 668 fixes the external dimensions and their tolerances; it does not fix the internal clear sizes, which vary with the wall and floor build-up a supplier uses.
| Unit | External L × W × H | External footprint | Note |
|---|---|---|---|
| 20 ft standard height | 6,058 × 2,438 × 2,591 mm | 14.8 m² | 6.058 × 2.438 = 14.77 m² |
| 40 ft standard height | 12,192 × 2,438 × 2,591 mm | 29.7 m² | 12.192 × 2.438 = 29.72 m² |
| 40 ft high cube | 12,192 × 2,438 × 2,896 mm | 29.7 m² | Same footprint, 305 mm more internal height |
Those are external figures measured over the corner fittings, and they are the ones that matter for transport, for stacking and for site layout. The floor you can actually use is smaller by the wall thickness on all four sides, so ask the supplier for the internal clear dimensions of the unit being quoted rather than assuming them from the external size. Doubling the length of a unit does not double its price either, because the ends, the door and the electrical entry are paid for once whether the unit is 20 ft or 40 ft.
For the size comparison in metric and imperial, including the flat-pack and expandable formats, see container house size.
Inside line 2 and line 3, a small number of decisions carry most of the difference between a cheap unit and an expensive one. These are the ones worth settling before the enquiry, because changing them after the drawing is approved is what turns a small order into a slow one.
| Decision | Cheaper option | Option that costs more, and why |
|---|---|---|
| Wall build-up | Single skin panel | Insulated sandwich panel: more material, and the unit holds temperature so the cooling load falls |
| Partition | One open room | Second room with a door: extra wall, extra door set, extra light and socket circuit |
| Sanitary pod | None, site toilet block used | Built-in toilet and basin: waterproof lining, waste pipework, water heater, ventilation |
| Cooling | Ventilation and fans | Split-unit air conditioning: equipment plus a larger supply and a dedicated circuit |
| Floor | Steel deck with a thin covering | Insulated floor with a wear layer: heavier, and it changes the lifting weight |
Each row changes both the price and the weight. Weight matters because it decides how the unit is lifted and how many travel on one shipment, so a fit-out decision made for comfort has a transport consequence as well.
When two quotations for a “20 ft site office” are far apart, the cause is almost always scope rather than efficiency. Normalise the five items below and the gap usually closes or explains itself.
| Item | What to ask for |
|---|---|
| Internal layout | A dimensioned plan with partitions, door swings and window positions |
| Wall and roof build-up | Panel type and thickness, and whether insulation is included |
| Electrical schedule | Number of sockets, lights and circuits, and the supply the unit expects |
| Climate equipment | Cooling and heating capacity, and whether the equipment is inside the price |
| Delivery terms | Named destination and incoterm, with lifting and offloading stated as included or excluded |
A lower unit rate with the electrical schedule added later is not the cheaper supply. The same applies to lifting: a price that stops at the port leaves the offloading to you, and a unit that needs a crane on arrival is a different site cost from one that a forklift can move.
One message with the following items is enough for a firm, itemised figure. Anything missing comes back as a question, and each round trip costs time on the production slot.
If the unit is part of a wider package, the drawing set can go with it in one go through send drawings. For how a fitted-out unit is checked before it leaves the workshop, see how we inspect.
The same shell is sold into three different jobs, and the fit-out is what separates them. A site office is desks, power and cooling. A shop or kiosk needs a shopfront, a counter and often a different door. A welfare unit needs washing, drying and toilet provision, which is pipework and ventilation rather than furniture.
If the requirement is a retail unit rather than an office, the cost structure shifts toward the frontage and the services connection; that is covered in what a container shop costs and what is included, with the product range on the shops and kiosks page. The office variants, including the dormitory format, are on the detachable container house page.
There is no list price, because a site office is quoted per unit against a scope rather than per square metre. Four lines sit inside the number: the shell, the internal fit-out, the electrical and climate services, and the transport and lifting. Two suppliers quoting the same nominal 20 ft unit can be far apart because one price includes the fit-out and services and the other stops at the shell. Send the unit count, the layout and the services you need, and ask for the quote split into those four lines.
The terms overlap in the market and describe similar products: a relocatable room used as an office on a site. What matters in a quote is the construction, not the name. Ask whether the unit is a bolted steel-frame module with a panel infill, what the wall and roof build-up is, and whether the floor is a steel deck or a timber deck. These three answers decide weight, insulation and how the unit can be moved again.
Not unless the quote says so. Transport is normally priced per unit against a named destination port or site, and lifting or offloading at the destination is normally the buyer's arrangement. A quote that names an incoterm and a destination is comparable; a quote that says only a unit price is not. Ask for the transport line separately so it can be checked against your own freight forwarder.
Yes, both are common, but each changes the structure rather than just the layout. Stacking adds corner and floor loads that need a frame designed for it plus a lifting plan; joining two units side by side means removing or opening a wall and closing the joint against water. Say at enquiry stage if stacking or linking is planned, because a unit ordered as a single-storey shell is not automatically suitable for a second level.
The unit arrives with a distribution board and internal circuits sized to the fittings ordered, and it needs a supply brought to it on site. The supply capacity, earthing arrangement and any local inspection requirement are site-side decisions, so tell the supplier the voltage and frequency at your site and which fittings you expect to run, including air conditioning and any water heater. The internal wiring can then be sized once instead of being reworked on site.
Yes. A shell-only unit is a legitimate order and it is often the cheaper route when local labour and local materials are inexpensive. The trade-off is that the insulation, lining, doors and electrical layout then have to be designed and inspected locally, and the unit may no longer match a repeat order from the same supplier. Decide the split before the enquiry, not after the quote.
The answer depends on whether the unit is a standard shell or a fitted-out layout, and on the transport route rather than the workshop alone. A repeat order against an approved drawing moves faster than a first order with a new layout, because the drawing and the fit-out details are already fixed. Ask for the production and transport periods separately on the quotation.
No unit price is published on this page. A site office figure is a sum against a scope, a unit count and a destination, and a number written without those three things would be wrong for almost every reader of it.