Tyres, sheep wool, beer cans. We have seen it all in sustainable buildings, but what are the sensible alternatives to bricks and cement? How can we prepare for the future with buildings that function effectively for the modern inhabitant, that are efficient, and most of all are sustainable?
With the number of households in England projected to grow to 27.8m in 2031 according to a Government report in 2009, every viable alternative needs to be considered. It doesn’t stop here. The housing problems in England are dwarfed by that of the 600m urban dwellers in Africa, Asia and Latin America who live in life, and health threatening homes.
Sustainable alternatives range from the less conventional houses being built in old whiskey barrels by the Findhorn Foundation in Scotland, to the more conventional BedZED development built by the Peabody Trust in south London. These are small scale, so what is the answer to the global housing problem?
This set us thinking, sustainable housing is a global issue and what could we do at Tongji University in China to help? We’re a long way from London, Scotland and the sustainable housing projects being developed elsewhere in Europe and the US, but we do have access to an enormous supply of one particular sustainable raw material, namely bamboo.
So how can the 1.2bn stalks of bamboo grown in China each year help sustainable housing project outside China? Isn’t bamboo’s only use in construction for the rickety scaffold often seen in far-east building projects? True, this is one use, but it is also one of the oldest materials used for construction of houses, and in Latin America bamboo bahareque and quincha houses of over 100 years old are still being lived in. One billion people already live in bamboo houses. In Bangladesh as much as 73% of the population do. But this is the twenty first century and I am the first to admit that some of these houses do not match the standards we should expect.
However, China produces 31m tonnes of product every year. It has an annual growth cycle and China is investing heavily in the sustainable farming of it. It is adaptable, flexible, durable and available in mass quantity – the question is how we utilise it in twenty first century construction.
There was something we could do to overcome this challenge. We created the global bamboo housing programme along with ENN Group a provider of integrated clean energy solutions in China. Our mission is to promote the substitution of unsustainable building materials with environmentally friendly bamboo for construction – where appropriate – to provide solutions to the shortage of proper housing for the poor, and to develop housing related livelihood options.
Bamboo house of the future
We wanted to deliver the next generation of bamboo houses. The design we developed reflects the energy-saving concept and aesthetic elements of Chinese traditional architecture, combined with modern solar PV technology. The house uses “fanyu” roof structural elements like those of Chinese traditional architecture so that the curved roof is able to maximize the electricity-generating efficiency of the solar panels and provide good ventilation, cooling and drainage capabilities.
The Tongji House, as it is affectionately known, is a one-bedroom-one-foyer configuration, made from 94m3 of bamboo. It resembles the characteristics of Chinese traditional waterfront houses and can, at the same time, improve the microclimate of the outdoor residential environment. In addition, the bamboo house utilises a smart control system where data regarding the house’s capacity, energy consumption and environment can be viewed directly by the home’s occupants. It is estimated that the energy capacity (kWp) of the bamboo house we created is three times its actual energy demand, which means that each house is able to become an energy plus house. Based on the measurement data, it gives back 30-40 kWh to the power grid.
Our bamboo house was built for the recent European solar decathlon. At €250,000 build cost it sounds expensive, but for a concept house it is not. Mass production would greatly decrease the costs involved. With the support from ENN, a Chinese clean energy company, we’re furthering our research, taking it beyond this prototype and looking at how to optimise the structure, enhance power generation and consider multi-energy resources into the house such as biomass and wind energy.
There are many benefits of bamboo housing. Affordability, employment generation, availability of raw materials, adaptability, flexibility, speed of construction, durability, comfort, control of deforestation, and the list goes on. Perhaps it is not such a pipe dream, and in five years time people driving through the English countryside might catch a glimpse of the latest bamboo village.
Bamboo is a versatile and sustainable construction material. If you find yourself in China, our house is currently demonstrated in the Jiading Campus at Tongji University, so come and take a look.
Professor Hongwei Tan of Tongji University