During London Design Week, the Building Centre in central London hosted the latest prototype of an alternative approach to low cost housing.
Sitting on the Centre’s forecourt was Arup’s latest offering in this field, following on from the WikiHouse that occupied the same site a year ago.
This time the 28m2 house was based on two recycled shipping containers and building costs were estimated to be as little as £25,000. In the future, however, new high strength steels could be used to save weight and make such houses significantly more sustainable.
Arup and design team partner Carl Turner Architects believe that these “narrowboats on land” could be craned into position and installed very rapidly on rented land or city centre brownfield sites. Arup has committed to making the research and experience of the prototype available as Open Space information for anyone interested.
Currently there are more than 20M general purpose ‘intermodal’ shipping containers in use globally, of which more than 1M are discarded annually. These come in a range of lengths and heights, but 6.1m long by 2.44m wide by 2.59m high containers as utilised by Arup can be purchased for between £1,500 and £2,500, making them a popular choice for self builders world wide.
The two linked containers that make up the Building Centre house demonstrated different approaches to insulation and cladding. One was insulated externally with 80mm high performance polyisocyanurate (PIR) rigid insulation boards and clad in timber. The second used similar insulation, but fixed internally, with the container shell simply painted externally. Both had underfloor insulation.
Arup associate director Adrian Campbell says the finished house complies with all current building regulations on insulation. ‘We’ve paid particular attention to thermal bridging, a potential problem area.
“There’s nothing new about converting shipping containers into housing, but there have been problems with earlier designs. This house is our response to these problems.”
Each container is topped with a steel deck supported on the end structures originally designed to allow the containers to be stacked up to 10 high when fully loaded. A kitchen garden has been established on one deck, a sun terrace with plants in tubs on the other.
There’s nothing new about converting shipping containers into housing, but there have been problems with earlier designs.
Adrian Campbell, Arup.
Adding these decks pushed total building costs up to around £30,000. Internally the house featured the latest version of the low voltage direct current (DC) lighting system first demonstrated on last year’s WikiHouse. “This approach can demonstrate significant savings in energy usage”, Campbell says.
“We’ve also added a lithium ion battery to take advantage of off-peak or renewable energy. It can store 3kWh of electricity, enough to satisfy the house’s needs for up to 10 hours in a typical day.”
Also featured internally were mood sensitive lighting and voice actuation systems for the services. A modular approach has been adopted for the internal fit out.
Arup project director Stuart Smith says the house “challenges our notion of the space we need to live. Floor area is less than standard London guidance, but it offers flexibility, adaptability and access to the city.
“The question is ‘could you live in this’?”
Judging from the booming popularity of steel narrow boats as permanent residences in London, where total floor area is usually well below normal recommended minimums, the answer is likely to be positive. Carl Turner Architects has been working on recycled container-based housing design for some time and sees this as one of the best options for self-builders.
Brazilian mining company CBMM technical consultant Dr Jitendra Patel, however, sounds a note of warning. “Second hand containers are usually well travelled and have taken a battering,” he says. “And the doors, which have obviously to be very secure, are heavy and superfluous in housing applications.”
CBMM is a major exporter of ferroniobium, a key component of high strength steels. Currently a major UK container manufacturer is developing a container design using significantly higher strength alloys than the norm. Patel says the aim is to cut the weight of containers by 20% or more, with obvious benefits for overall cargo capacity or fuel consumption during transport.
He adds: “Our first prototype should be ready in three to four months. But we’ve also been exploring with Arup other possible uses for high strength containers, the obvious one being the housing market.”
High strength containers would use less steel and be more sustainable. In the longer run both CBMM and Arup believe that large scale use of “container” housing would require the manufacture of specialised steel shells without heavy and expensive security doors. These could be stacked up to 15 storeys high, Arup has calculated.