Hi-tech Low-tech: an experimental sustainable house

Why should we think it is sustainable to buy a prefabricated wood house in northern Italy and to assemble it 1000 km far away in southern Italy? Which features should a small house have in order to be suitable for southern Italy climate and landscape? The design team I belong to, tried to give an answer to this question by taking part to the Italian Ministry for Environment, Territory and Sea competition Ecoluoghi 2011 to design a 45m2 sustainable house. The project “Low-Tech High-Tech” was awarded, with other projects, in 2011 and the prototype of the house was built and eventually exhibited at the MAXXI Museum (National Museum of the 21st Century Arts) of Rome in summer 2012. The name we chose for the project, “Low-Tech, Hi-Tech”, well embodies the concept that lies underneath it: to take advantage from this apparent opposition of terms. Method The prototype made it mainly possible to test the constructability of the project on the base of the following “sustainability” criteria • to reduce long distance transportation of heavy materials • to concentrate the hi-tech performance in few elements of the building • to support local economy • to favour the integration with the local landscape • to maximize the reuse of building material • to minimize the consumption of soil and non-renewable energy • to keep costs affordable Results From the “Low-tech” approach we took some “vernacular” elements belonging to southern Italian architecture: thick stone walls with small windows, tall roofs to facilitate the hot air stratification and circulation, open shaded spaces where to expand the activity of the house; from the “High-tech” approach we employed high thermal performance materials to minimize heat losses, a convertible winter garden made of EFTE air cushions, solar panels to gain thermal and electric energy and high performance heating plant. The Low-tech domain capitalized on simplified building techniques, recycled or easily available materials and implied making use of local unskilled manpower. The “Hi-tech” area applied, instead, to technologically more complex building elements, often produced in far areas of the country and requiring skilled work. In Mediterranean countries, where mild winters alternate to hot summers, the internal comfort is essentially stemming from a good control on irradiation thermal gain and from a good ventilation of the rooms. Here below we provide a description of the features of the house according to the principles of sustainability, constructability, adaptability, comfort. • Sustainability The Low-Tech elements of the house are: the load-bearing 55 cm thick wall, combining a high thermal inertia (16h), and good insulation (0.27 W/m2 K), and the external coating in local stones without mortar (as if for the construction of a dry wall). This is contained in wire mesh gabions and has the function to protects the wall from solar irradiation. High-tech elements included in the project are the winter garden structure and the windows. The winter garden, with low temperatures, has the task of working as a buffer zone between the outside and the glass wall to the south. • Adaptability In order to reach the goal of adaptability to the landscape and use, we applied the camouflage approach by recycling part of the material extracted from the excavation to cover the external walls. The need of “adaptability” to different weather conditions was met by transforming the traditional “porch” in a year-long liveable place, where residents can spend their time out-door also with different climatic conditions. • Comfort Interior comfort is based on the use of natural resources (sun, wind, water and soil), by focusing on the integration of active and passive behaviour of the house. The house, according to the calculations of the testing model, is ranked class A with an average consumption of 25 kWh/m2 year. Constructability Building up the “Low-tech” part of the house is easy to do. The “Low-tech” consists of heavy masonry envelope. This does not require skilled workers and materials can be found on the local markets. The external coating is an evolution of the traditional dry stonewall, with stones taken from excavation made in the local soil. We use box shaped elements made with steel mesh. The High-tech elements are mainly represented by the winter garden, the windows, and the mechanical plants. They all need skilled workers and transportation from distant markets. Conclusion The “Low-tech high-tech” house embodies a combination of a semi-prefabricated and a semi-handmade building at reasonable costs. Without the need to repeat vernacular house type, simplified technologies (low-tech) have been used wherever these proved to be compliant with the required performance, whereas advanced (hi-tech) technological solutions were applied to obtain the highest levels of performance. The results show a possible perspective to look at the issue of southern Europe sustainable house building.