Bioclimatic design for homes

Holiday houses are a mixed blessing, as their owners can confirm. The joy of having a home away from home in one’s dream environment, whether by the sea or in the countryside, is usually tempered by problems of damp and mold, poor insulation and – in newer homes where traditional methods have gone by the board – the wrong choice of material or poor orientation of the house. In the pre-mass production age, local conditions and materials dictated the means of construction of traditional Greek homes to take advantage of wind direction, sunlight and other natural phenomena that have largely been ignored in more recent decades. Bioclimatic architecture is using these principles coupled with modern technology to create more energy-efficient and sustainable houses. In an ongoing series of seminars run by the Hellenic Society for the Protection of the Environment and Cultural Heritage, architects Elli Georgiadou and Agnes Couvelas spoke about the application of bioclimatic techniques to holiday homes on the Aegean Islands and in Xanthi, in the far north. Xanthi Elli Georgiadou, who has used bioclimatic techniques since 1985, applied them in 1994 to the design of a small family home in the countryside of Xanthi, in Greece’s northeast. It was unusual in that the construction materials were designed so that it was possible for the family members to build the house themselves with very little outside help (chiefly in the bricklaying and installation of doors and windows). The brief was for a low-cost and ecologically sound home of easy maintenance. A sloping roof descends almost to the ground level on the northern side to deflect strong winds, while the southern side was fronted with a greenhouse and swimming pool that is solar-heated in the winter. The timber frame’s beams were restricted to a size and weight that could be lifted by two people. The timber used was pine, which is long-lasting, treated with borax to kill parasites, and then one or two layers of oil and a varnish that does not create a membrane on the wood. Lime and casein, using natural pigments, were used on the walls. A tank at the rear of the house collects rainwater runoff from the roof. As there are no specifications in Greece for the use of clay walls, which offer optimum qualities for an ecologically sound construction (an estimated 50 percent of homes around the world are built using this material), brick was chosen for the outside walls of the house. Window frames were insulated with jute, a plant fiber, instead of rubber, which releases toxins into the atmosphere. The north-facing rear of the house is where the auxiliary areas (bathrooms, kitchen and storeroom) were sited, providing further protection for the living areas. The total cost of the 100-square-meter house in 1994 was 7.5 million drachmas (in today’s terms just over 20,000 euros). Santorini Agnes Couvelas’s design for a summer home on the island of Santorini (designed in 1993 and completed in the summer of 1994), made use of the force of the strong meltemi winds that blow at that time of year to help cool the house without creating drafts. Located in a conspicuous high position overlooking the settlement of Akrotiri, the building is exposed to strong northerly winds. Funnels formed within the mass of the casing deflect the wind entering them, thus creating a protective «wind curtain» in front of the corresponding windows. So the shell is resistant without being hermetically sealed, providing a view of the caldera to the north without the continuous interpolation of glass panes. Shutters are on the inside for easier use and to be protected by the windows when closed. The building’s structure was modeled as if dug out of soft material, in a reference to the local technique of dug-out subterranean spaces (hyposkapha). The main rooms on both floors open out onto a main veranda area between the two wings of the upper story serving as the «meeting area» for the household to eat and relax, and also face the view. The incline of the outside walls recalls the goulades, the fortress structures of the past on the island, in particular the one at Emborion. «The openings in the building attempt to enter into a dialogue with the windows in the ruined prehistoric city. Their irregular shape, as if created by long years of decay, will later bear traces of real wear and tear,» said Couvelas. Cinder blocks – a light and easily worked material with good thermal properties, coarse local sand, pinkish colored for the coat on the external surfaces, and pumice for insulation were used in the construction. The floors are paved with cement tiles of local sand in a similar shade. The house was plastered with a local material that changes hue according to the weather.