12-Unit Two-Storey Detachable Flat Pack Container House: 17 Sets per 40HQ

A twelve-unit detachable flat pack container house project, arranged as six modules on the ground floor and six above, has become the clearest demonstration of why packing efficiency now decides the landed cost of a modular building. Each module measures 6000 mm long, 3000 mm wide and 2840 mm high. Seventeen sets travel in a single 40HQ container; a 20GP takes seven.

For buyers comparing container house price per square metre across suppliers, the number that matters is rarely the quote per unit. It is how many units fit behind one set of freight charges. A detachable container house is a bolted steel frame with removable wall panels, and because the frame, panels, roof and joinery all travel as a knocked-down kit rather than as a finished box, the same container volume carries several times the floor area of an assembled unit.

Seventeen sets in a 40HQ, seven in a 20GP

The loading figures for this model are straightforward, and they are the reason the project could be priced as a single shipment rather than a sequence of them:

The 17-set and 7-set figures are quoted without the electrical wiring package and the PVC floor covering, which travel separately. Final loading is confirmed on the packing list for each order, because panel thickness, window count and door specification all change the stack height.

Twelve modules is therefore well inside one 40HQ. A buyer planning a small resort block, a staff camp or a two-storey site office can ship the entire building — structure, panels, roof, doors, windows and stair — in a single container, and pay one set of ocean freight instead of six or twelve. For projects that need a container dormitory or a container office at short notice, that is usually the difference between a viable landed cost and a quote that never closes.

Installation: bolted, not built

The second half of the saving is on site. A detachable container house is assembled from the frame outwards with hand tools: the galvanised floor beams interlock at the corner castings, the columns are bolted up, the pre-sealed roof goes on as one piece, and the insulation panels slide into the frame tracks. No welding, no wet trades, no blockwork, no render.

The sequence for a two-storey arrangement is the same sequence run twice, with the upper modules landed on the lower ones and tied through the corner castings. Because the module is a rigid bolted box rather than a folded panel system, the upper floor can be lifted and positioned straight onto the level below it, which is what makes a six-over-six layout practical on a site with no crane pad and no scaffolding budget.

• Foundation: pre-cast concrete piers or a levelled hardstanding at the corner points. No slab is poured, which matters on a leased site or an olive grove where excavation is not permitted.
• Ground floor: six modules set side by side, bolted to each other along the shared frame line to form one continuous floor plate.
• Upper floor: six modules landed on top, aligned to the same frame grid so the vertical loads run straight down through the corner castings.
• Envelope and trim: panels, glazing, doors, louvres and the external steel staircase are fitted after the structure is closed, so the building is weather-tight before the joinery starts.
• Services: the electrical package is pre-wired to the frame with a distribution point, connected on site to the incoming supply.

What the module itself is

The structure is a 2.3 mm to 3.0 mm spray painted galvanised steel tube frame, with 50 mm, 75 mm or 100 mm rock wool, EPS or PU sandwich panels finished in 0.3 mm to 0.5 mm colour steel plate. The roof is 0.42 mm colour steel over insulation with multi-layer waterproof sealing, delivered pre-assembled. Floors are 15 mm or 18 mm MGO or cement fibre board, with PVC floor leather as the standard finish and a heavier build-up available for wet areas.

None of that is unusual for a prefabricated container house. What changes between suppliers is how the panels are detailed at the joints, how the roof is sealed before it leaves the factory, and whether the frame is genuinely bolted or welded shut — because a welded shell cannot be taken apart, and a detachable container house that cannot be detached has lost the point of the system.

Two storeys, one frame grid

Stacking is where a detachable system earns its place over a flat pack one. Both are knock-down, but a detachable module is assembled into a rigid box before it is lifted, so it can carry a second storey without a separate structural frame. In this project the result is a twelve-module building with a continuous balcony along the upper floor, an external steel staircase at the rear, and a ground floor opened up with glazed bays onto a timber deck.

The finish matters as much as the structure at this scale. A two-storey block of twelve modules reads as a building rather than a stack of cabins only when the frame lines are aligned and the colour scheme carries across both floors — here a warm sand panel with an anthracite frame, so the module joints become part of the elevation instead of something to hide.

Where this configuration fits

• Boutique resort and glamping: six guest units above, six below, with the balcony as circulation and the deck as shared outdoor space.
• Staff accommodation: a container dormitory block for a remote site, shipped complete in one 40HQ and assembled without heavy plant.
• Site office and welfare: a container office on the ground floor with meeting rooms and a canteen above, relocatable when the project ends.
• Sales and hospitality suites: a two-storey pavilion that can be dismounted after a season and rebuilt on the next site.

What to ask a container house manufacturer

When comparing quotes for a detachable flat pack container house, four questions separate a real number from an optimistic one. How many sets actually load into a 40HQ once the electrical package and floor covering are counted? Is the frame bolted or welded? Is the roof sealed and tested before it leaves the factory, or on site? And what is the assembly sequence for the second storey — which is where most site delays appear.

Asked in that order, the answers usually explain the price difference between two quotes for what looks like the same container house.

The photograph above is the standard module as it leaves the factory. Glazing, louvres, colour finish, staircase and decking shown elsewhere in this article are configuration options on top of that module, confirmed on the drawing for each order.