ARTICLE Jason Burgess

Since the new millennium shipping containers have been upcycled for everything from multi-level community housing project, student accommodation and temporary shelter for refugees to inspired high-end, multi-pod private abodes for those who celebrate out-of-the-box architecture. The idea though is not new.

During the 1960s, late modernist architects were devising ways of repurposing containers into modular living spaces. In the 1970s, the UK container home architect Nicholas Lacey, outlined the concept in his university thesis. Then, during the first Gulf War, the US Army ran with the idea, repurposing containers for emergency housing. Sceptics still argue that the reported flexibility of container homes is limited and conversion costs are comparable to standard builds. The proponent counter claim is that long-term benefits outweigh the short-term economics.

No matter which side of the steel box you sit on, it is clear that shipping container homes are growing in popularity and the passion of container coverts is contagious! 

Yellow shipping container transformed into modern home

With an estimated 20 million plus containers on the high seas and at least double that number sitting dormant on dry land at any one time, there is no shortage of source materials for container homes. That said, not all containers are going to meet muster when it comes to sign off time. The rule of thumb is buy only single-use containers. ‘High cube’ containers provide a very workable 2.69m high interior ceilings and allow for regular height cupboards. 

Avoid containers with dents and rust spots, otherwise proving structural integrity and 50-year lifespan to council with a headache. Make certain to view container/s on falt ground to check the doors and locks are working. 

Look for evidence of a hazardous goods sticker (in case the container carried something toxic) and do a sniff test to ensure there is nothing malodorous lingering.

The main issue for container home conversions in New Zealand is educating councils.

“Container homes are still a relatively new idea,” says Brenda Kelly from IQ Container Homes Limited, “some local bodies may be resistant, especially if they have only every dealt with cowboys.”

Wherever you propose building, do not start the footings until you have properly researched local planning laws and acquired the relevant permits.

Architects and designers working on plans for residential project

The common misconception is that DIYer’s can buy any old container and knock a few holes in it. Brenda warns that converting a container home requires a good few years of R&D. An open communique with council is crucial, as is establishing relationships with like-minded engineers and builders. 

“If tradespeople have not done a conversion before then you will be paying money to get them up to speed, too.” That’s why it pays to have someone managing it all.

The strength of a container is achieved when all the components work together in unison. The two long walls act as bracing, but only the corners are weight bearing. The Corten steel walls are comprised of a double skin; they are ‘soft’ – making cuttings for windows and doors relatively easy with a reciprocating saw or grinder. Remember, anything cut out of the walls must be engineered and compensated with additional support. Talk to your renovation builder for help with this. 

Open-plan multi container builds will require extra beams to support the roof and meet code. Thermal efficiency needs to be proven too. Achieving the right balance of doors and windows to maximise light and cross-ventilation will require careful planning and design engineering.

Blue shipping container from the front, with a floor to ceiling glass entrance and windows

A wall of windows in a single container will not allow much latitude of energy efficiency calculations. Aluminium double-glazing is the recommended minimum for windows and ranch sliders. IQ opts for a lightweight UPVC joinery that offers superior energy efficiency and some soundproofing qualities too.

The great thing about containers is that while the pods are being converted and prepared off site, all the groundwork, engineering and placement of piles and running of services can be happening simultaneously on location.

As containers take weight at their corners, timber piles beneath each corner will provide suitable foundational support in most scenarios. This makes them ideal candidates for a sloping site. Elevating containers off the ground will help provide airflow and easy access to all your services.

A container will ‘sweat’ and develop condensation so insulation is critical. 

“It pays to avoid Batts,” advises Brenda. “We used a closed cell polyurethane foam and sprayed directly on the steel. This forms a vapour barrier, with a high R-value per square inch. This achieves 1.5 x the building code minimum and encroaches only 45mm into the interior space.” 

For ease of applications and to amplify the sense of space, IQ opt for 12mm ply ceilings and walls painted white throughout. Ply offers a sturdy lining, makes it easy for attaching artwork and furnishings, and won’t crack when containers are transported.

Underfoot, a timber-look PVC flooring suitable for wet and dry areas provide a clean one surface finish. 

Colored shipping containers stacked to create living block

Container roofs are a contentious issue with council. Code compliant roofs need a minimum 3-degree pitch, while container roofs are designed with a very small 5-degree camber either side. 

Container roofs should not be penetrated so IQ has devised a custom gutter system welded to the topsides of the container with spouting at each end to dispel the water. If you are planning to add on more than one container, your renovation builder will need to fit an external mono pitch roof to avoid the pooling of water at the joins. This will require additional engineering and strategically-placed cleats welded to the roof area. This will provide easy connection points for onsite installation of both roof and gutters. 

Some renovators prefer disguising their container facades, but as Brenda says, “Once you add cladding then you are into regular maintenance. We use a specialist water-based steel paint that meets 50-year durability code requirements, only needs repainting every ten years and also means we can collect water in our off-grid model. Fortunately, now the container look has come into its own and people are embracing them as modern and funky.”

For more renovation project ideas visit our Case Studies gallery.

 

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