Technical Resource

Shipping Container Homes: What to Know Before Buying the Containers

A container home starts with steel boxes but succeeds or fails on design, permits, insulation and the foundation. This guide covers what a buyer needs to settle before ordering the containers: which layouts work, how much floor area each box gives, which size and grade to choose, the rules that apply in the US, and how the boxes reach the site. MG-Atlantic supplies the containers; design and construction are the work of an architect, an engineer and a builder.

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Layouts

Container home plans and floor areas

Most container home plans combine a few standard modules. The inside of a 20ft box gives about 150 sq ft (13.9 m²) of floor, a 40ft or 40ft high cube about 300 sq ft (28 m²). Every module is about 7 ft 8 in (2.35 m) wide inside, which is why plans join boxes side by side or open them onto each other.

Studio or cabin: one 20ft or one 40ft high cube, about 150 to 300 sq ft.
One-bedroom: one or two 40ft high cubes in line or side by side, about 300 to 600 sq ft.
Two or three bedrooms: three or four 40ft high cubes, side by side, in an L or a U around a courtyard, or stacked on two levels.
Removing the walls between two boxes doubles the room width, but each removed wall must be replaced by a beam and posts designed by an engineer.

Which containers

Choosing the size and the grade

The 40ft high cube is the usual module for a home. Its inside height of about 8 ft 10 in (2.69 m) still leaves around 8 ft once the floor, the insulation and a ceiling are in; a standard 8 ft 6 in box leaves well under 7 ft 6 in.

For a home, new (one trip) containers are the usual choice: straight panels, intact paint inside and out, no cargo history and fewer dents to correct before framing. A sound cargo worthy unit can work for a cabin or an outbuilding if the buyer accepts more surface preparation. Buy every module of a project in the same size and, ideally, from the same production batch, so heights and door positions line up.

Shipping container floors are hardwood or bamboo plywood treated against insects for ocean transport. For living space, builders usually seal the original floor under a new subfloor or replace it.

Rules

Permits, zoning and building codes

In the US, a container home is a building like any other: it needs the zoning to allow a dwelling on the lot, a building permit and inspections. Some counties and HOAs restrict container or modular homes; check with the local planning department before buying anything.

Since the 2021 editions, the model codes of the International Code Council cover shipping containers used as buildings (International Building Code, Section 3115), and many jurisdictions apply them or their own rules. Expect to provide stamped structural drawings, especially where walls are cut or containers are stacked, and to meet the local energy code for insulation.

Comfort

Insulation, condensation and openings

Steel conducts heat and sweats when the inside is warmer and more humid than the shell. A living space needs continuous insulation with a vapour barrier on the warm side; closed-cell spray foam is common because it follows the corrugations and seals at the same time. Our insulation and condensation guide compares the options.

Every door and window opening is cut into a load-bearing wall and must be framed in steel and sealed. Plan the openings with the engineer, not on site.

Budget

What drives the cost of a container home

The containers are usually a modest share of the total. The budget is driven by the foundation, the steel work for openings and removed walls, insulation, windows and doors, plumbing, electrical and heating, interior finishes, transport and the crane for placement. A design that keeps walls in place and limits openings costs less than one that opens every box.

On site

Foundations, delivery and placement

Container homes sit on concrete piers, strip footings or a slab, with the corner castings anchored to embedded plates. The engineer sizes the foundation for the soil, the frost depth and the wind or seismic loads of the site.

Containers for a home are usually set by crane rather than slid off a tilt-bed truck, because they must land precisely on the foundation and, when stacked, on each other. Plan crane access and a staging area before the delivery is booked.

Frequently Asked Questions

Shipping container homes, answered

One 20ft or 40ft high cube for a studio, one or two 40ft high cubes for a one-bedroom, and often three or four for two or three bedrooms. The layout, and whether walls are removed between boxes, decides the number.

The 40ft high cube. It gives about 300 sq ft of floor per box and about 8 ft 10 in of inside height, which leaves around 8 ft once insulation and a ceiling are added.

Yes, where the zoning allows a dwelling and the home is permitted and inspected like any other building. Rules vary by county and HOA, so check with the local planning department before buying containers.

New (one trip) containers are the usual choice: straight panels, intact paint and no cargo history. A sound cargo worthy unit can suit a cabin or an outbuilding with more surface preparation.

Original container floors are treated against insects for ocean transport. For a home, builders usually seal them under a new subfloor or replace them.

Decades, when the roof sheds water, condensation is controlled and the paint is maintained. Corrosion, not age, is what limits a steel shell.

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