Portable Construction Site Cabin: Six Site-Duty Sizes

Site office cabin or site office container? Start here

Two different products answer the phrase site office, and buyers land on both with the same question. One is a steel-framed cabin built from scratch on a welded chassis, delivered in the size the drawing says and in a colour chosen for the job. The other is a used ISO shipping container cut and lined into an office, fixed at container dimensions because that is what the box already is. This page is the first of those.

The difference matters on a construction site more than anywhere else. A cabin is built to a wall-opening schedule, so the door lands where the site access is and the windows land over the desks rather than wherever the container corrugation allowed. Widths are not tied to 8 ft: this range runs 8, 10 and 12 ft wide, and the 12 ft width exists specifically so a drawing table has an aisle. A cabin is also lighter for its floor area, which matters when the only crane free to place it is the one already erecting the structure.

If the container form is what you actually want, whether for the stack strength, the lock-up security or the look, that is a separate approved product and it has its own page: the SAMAN site office container. Nothing on this page is a container conversion, and no size here is derived from a shipping container.

Who works in a site cabin, and where it actually stands

The people this cabin is specified for are the ones whose day is spent between the room and the works: the site engineer, the project or contracts manager, the planner, the safety officer, the store or document controller, and the labour supervisor who comes in with muddy boots and leaves again in four minutes. None of them treat the room as an office in the ordinary sense. The door opens perhaps two hundred times a day, drawings are laid flat rather than filed, and half the furniture is only there because something has to hold the site register.

Where it stands is just as particular. A site cabin sits inside the hoarding line on ground that was a field or a demolition slab a month ago, usually on a temporary plinth or on packed rubble rather than a foundation. It is close enough to the works to see them and far enough back to be outside the crane drop zone, which means it will be moved at least once as the structure comes out of the ground and the site layout changes. Access is a haul road, not a service yard: the delivery trailer needs turning room and the crane needs a marked pick-up point on the shell.

Because the unit moves, everything about it is specified for repeat lifting rather than for one placement. That is the single largest difference between this build and a cabin that will spend its whole life on a paved compound, and it is why the lifting lug positions are painted onto the shell rather than left for the rigger to work out.

What site duty changes about the shell and the openings

The shell is the same welded steel platform SAMAN uses across the cabin families: a 100 × 50 × 3 mm MS C-channel base chassis, 50 × 50 mm hollow-section top and wall framing with reinforced openings, 1.2 mm corrugated MS external walls and a 1.4 mm corrugated MS roof with sealed laps and flashings. Walls are 100 mm thick. Inside, 8 mm prelaminated MDF lining with aluminium joint sections runs to an 18 mm cement-fibre floor board finished in 1.3 mm vinyl. Roof insulation is 50 mm glass wool at 42 kg per cubic metre; walls take 25 mm glass wool or the documented 12 mm Heatlon option.

What site duty changes is where things sit and how they are protected. Every window in the range is a 4 ft two-track aluminium sliding unit with 4 mm glass, and every one of them carries a fixed protective grill on the outside. That grill is not a security afterthought; it is what stops a length of pipe or a bundle of shuttering ply leaning against the glass. The door is a single outward-opening MS-framed leaf, roughly 7 × 3 ft, set in the front wall and raised clear of the mud line so the threshold sheds boot dirt outward instead of collecting it.

Electrical work is concealed copper wiring on typical 1.5, 2.5 and 4 sq mm circuits with a distribution board carrying isolation, MCB and RCCB protection plus earthing, segregated between lighting, sockets and the air-conditioning provision. The provision is a point and a circuit; the unit itself is quoted separately. Corrosion protection is prepared MS with red-oxide primer and two enamel coats, and each of the six sizes ships in its own approved exterior colour so a fleet on one site can be told apart at a distance.

Choosing between 100, 160, 200, 240, 300 and 400 sq ft

Size on a construction site is decided by two numbers that have nothing to do with floor area: how many people need a desk of their own, and how wide the aisle has to be for the biggest drawing that gets opened in the room. Work those two out and the size chooses itself, because the desk count is staged on the GA drawing rather than left to the buyer.

Read the table by the desk column first. The 20 × 8 ft stages fewer desks than the smaller 10 × 10 ft, which looks wrong until you see why: at 8 ft wide only one desk run fits, so its three desks sit in a single line on the rear wall, while the square 10 × 10 ft puts four desks around three walls. The 20 × 8 ft is not bought for capacity, it is bought because a 10 ft module will not physically go where it has to go.

The step from 20 × 10 ft to 20 × 12 ft buys no extra desks at all. Both stage five. The two feet buy aisle, and the buyers who pay for them are the ones who hold the weekly progress meeting standing around a drawing in the site office rather than in a separate meeting room. If your drawings live rolled up in a tube, the 20 × 10 ft is the better value; if they live open on a table, the 20 × 12 ft is the size to order.

Below 100 sq ft this page stops. A gate room, a single-supervisor cabin or a security post at 48 to 80 sq ft is a different product and is priced on the small office cabin page. Above 400 sq ft the price rule continues in published bands to 900 sq ft, and beyond that the size is quoted manually rather than listed.

The two-door 30 × 10 and the partitioned 40 × 10 plan

The two largest sizes are the only ones that change the plan rather than just the dimensions, and both changes exist for the same reason: at eight desks and above, a single door stops working.

On the 30 × 10 ft, eight desks are staged three along the front wall and five along the rear. With one central door, anyone reaching the far end walks the full length of the aisle past six colleagues, and the room has one way out. The approved plan puts a 3 ft door near each end of the 30 ft front wall instead, which splits the traffic, lets the far desks be reached directly, and means the drawing table can be placed mid-wall without becoming a corridor. Four of its eight windows run along the rear wall, one over each pair of desks.

The 40 × 10 ft is the only size in the range delivered with a partition already built. A full-height partition 10 ft in from one end wall creates a 10 × 10 ft manager room with its own 4 ft window and its own 3 ft internal door, opening off the common office. What is left is a 30 × 10 ft open office staging twelve desks, five on the front wall and seven on the rear, served by two external doors on the 40 ft front wall. Ten windows are scheduled in total, one of which belongs to the manager room.

That partition is worth ordering rather than adding later for one practical reason: a site manager takes calls and holds conversations that the room should not hear, and a partition built into the module on the shop floor is straight, lined on both faces and finished to the same standard as the shell. A partition put in on site after delivery is a carpentry job on a floor that is already in use.

What the published price covers and what is quoted apart

Every price on this page is the finished cabin shell as described: chassis, framing, external envelope, roof, insulation, internal lining, floor, the scheduled doors and windows with their grills, the internal electrical installation with its distribution board, the paint system, and the lifting provision. It is quoted ex-GST, with 18 per cent GST shown separately against every size, and it is the same price whether the unit goes to a metro site or a district town.

What is not in it is everything that is site-specific, because pricing it blind would either overcharge the buyer or under-specify the job:

• Furniture, including the desks the layout is staged for
• Air conditioning units; the page price includes the point and circuit only
• Telecom, data cabling and any networking equipment
• Generators, incoming supply, and connection to the site distribution board
• Foundation, plinth, levelling and rough-ground packing
• Access stairs, landings and handrails
• Water, drainage and any sanitary fit-out

Freight is published separately by trailer size and distance band on the shipping tab, with delivery free within Bangalore city and across Delhi NCR including Ghaziabad, Gurugram, Faridabad, Noida and Greater Noida. Crane hire at the receiving end is arranged by the site, since the crane that lands the cabin is almost always one already on hire to the project.

Two things commonly bought alongside a site cabin sit on their own pages rather than being folded into this one. Workforce accommodation is priced as a labour colony, and standalone sanitation is priced as a portable toilet. Ordering them together is normal; pricing them together is not, because the quantities never scale the same way.

Common questions about construction site office cabins

What size site office cabin do I need on a construction site?

Count the people who need a desk of their own. Four fits the 100 sq ft 10 × 10 ft, five the 200 sq ft 20 × 10 ft, eight the 300 sq ft 30 × 10 ft, and twelve plus a manager room the 400 sq ft 40 × 10 ft.

Is a portable site cabin a temporary structure?

It is a relocatable one. The cabin is a welded steel module built to be lifted and moved repeatedly, with marked lifting points, rather than a permanent building fixed to a foundation.

Are the prices on this page inclusive of GST?

No. Every price is published ex-GST, and the figure including 18 per cent GST is shown alongside it for each of the six approved sizes.

Does the price include delivery to the site?

No. Freight is charged by trailer size and distance band and is published on the shipping tab. Delivery is free within Bangalore city and across Delhi NCR.

Can the door and window positions be changed?

The positions on this page are the approved schedule and are fixed on the GA drawing for each size. Any change is a drawing revision and is priced through a quotation, not selected on the page.

Why do the windows have grills on the outside?

The grill protects the glass from what leans against a site cabin: scaffold tube, shuttering ply and reinforcement. Every window in all six sizes carries one as standard.

Is air conditioning included in the cabin price?

No. The price covers the electrical point and circuit provision for an air conditioner. The unit itself, and its installation, are quoted separately.

How is the cabin lifted and placed on site?

By crane, using the lifting lugs designed into the chassis and marked on the shell. The site provides the crane and a level, compacted bearing or temporary plinth for it to sit on.