04Sustainability hub

Every green claim on this page has a number behind it

Reusing a container avoids the largest single lump of embodied carbon in a house: the frame is already made. The rest comes from building indoors, sizing systems against real loads, and keeping the floor area small.

At a glance

lb of structural steel reused per 40 ft unit: 8,000
kW typical array on a 40 ft roof frame: 6.4
per cent less construction waste than a site build: 65
gallons caught per inch of rain on a 40 ft roof: 900

Materials with a first life

Every unit starts as a retired one-trip or Grade B container that would otherwise sit in a depot or go to the shredder. We buy the frame, not the trip.

A 40 ft high-cube contains roughly 8,000 lb of Cor-Ten steel. Recycling that steel into new sections burns energy; reusing it as a structural frame does not. We source from depots within 300 miles of the yard, shot-blast rather than chemically strip, and specify low-VOC coatings throughout. Interior linings are FSC birch ply and the insulation is a water-blown closed-cell foam with a low global warming potential blowing agent.

8,000lb of structural steel reused per 40 ft unit

01Cor-Ten corrugated panel1.6 mm
02Zinc-rich primer and low-VOC topcoat—
03Closed-cell foam, sprayed to the profile50 mm min
04Service batten, held clear of the steel38 mm
05FSC birch ply lining18 mm

Solar as a system, not an add-on

The array is sized against your actual load and your actual latitude, and the roof frame is engineered for it before the container leaves the yard.

We model your consumption hour by hour rather than guessing at a panel count. The mounting frame is welded to the container corner castings, which are the strongest points on the structure, so there is no roof penetration and no ballast. Battery banks sit in a conditioned service bay because lithium loses capacity fast in an uninsulated steel box. Grid-tied units are specified for export where the utility permits it, and every off-grid unit is sized for four consecutive days without sun.

6.4kW typical array on a 40 ft roof frame

A smaller number at the end of it

Factory assembly, a reused frame and a small floor area compound into a build with substantially less embodied and operational carbon than a comparable stick-built house.

Three things do the work. The frame is already made, so the largest single lump of embodied carbon is avoided. The build happens in a yard, where offcuts are sorted and reused rather than skipped, and waste runs at a fraction of a typical site. And the finished floor area is small, which is the least glamorous and most effective efficiency measure there is. We issue an embodied carbon estimate with every fixed-price contract so the number is in front of you before you sign.

65per cent less construction waste than a site build

Water counted, not assumed

Rainwater harvesting, greywater reuse and low-flow fixtures are standard on off-grid units and available on every other model.

A 40 ft roof catches around 900 gallons from an inch of rain. On off-grid units that goes to a buried cistern, through a four-stage filter and into the house at potable standard. Greywater from the shower and basin is separated at the trap and fed to a reed bed or a subsurface irrigation loop where local code allows it. Fixtures are specified at 1.5 gpm or lower as standard, and every unit ships with a flow meter so you can see what you actually use.

900gallons caught per inch of rain on a 40 ft roof

05What you get handed

Three documents that make the claims checkable

An embodied carbon estimate

Issued with the fixed-price contract, before you sign, so the number is in front of you at the point it can still change the specification.

A blower-door test result

Every unit is tested in the yard at 50 pascals before it ships. If it leaks air it leaks vapour, and the yard is the last place fixing that is cheap.

A water flow meter

Fitted as standard so you can see what you actually use rather than what the fixture schedule said you would.

→Run your own numbers

See what the specification does to the price before you commit to it

Solar, rainwater harvesting and a plant room all have real costs, and they all appear as separate line items in the calculator. Add them, remove them, and see the range move.

Open the cost calculator Read the journal