a15 fabricates residence using straw and wood in northern italy

straw house by a15 follows alternative building methods

Architectural community a15 and designer Michael Reichegger demolish the lightweight construction of a prefabricated house to build a two-story structure using straw bales. Erected in 1976 in South Tyrol, Italy, the existing dwelling’s condition makes a comprehensive renovation unattainable leading to the complete dismantlement of the framework, retaining only the basement. The new two-leveled residence sits directly on top of the understructure’s trace reconstructing most of its form.

Aiming for an ecological, resource-conserving design, the project combines straw bales with wood to compose the framework. Straw as a building material provides an alternative approach to accomplishing high-quality planning in the areas of fire protection, moisture, pest infestation, acoustics, thermal insulation, and environmental compatibility. No pollutants, toxins, and hazardous waste are produced from the material production, through the shell construction to a possible conversion or demolition.

all images by Samuel Holzner

ecological & sustainable structure forms straw house in tyrol

The bales are stacked on top of each other and plastered inside and out to shape the house’s main volume. The 1.20m thick outer walls made of large bales of straw, wood, and plaster made of trass lime and clay ensure excellent thermal insulation, heat storage, room acoustics, and an all-around pleasant room climate. The false ceiling is made of solid wood, while the floor covering is executed as a fair-faced screed on the ground level and a solid wooden floor made of silver fir is laid on the upper level. The materials used for the new building should in future be able to be returned to the natural cycle without any problems. The new construction consumes very little energy and heating expenditure.

The southern facade of the residential building is completely glazed and guarantees a high level of solar heat input. The straw walls and ceilings provide excellent insulation and sufficient heating in winter. A small stove is installed on the ground floor for persistent bad weather conditions. To further increase the degree of self-sufficiency, a photovoltaic system is, also, installed on the roof, which covers the average annual electricity consumption. The natural precipitation is temporarily stored in the rainwater tank and used to irrigate the garden and outdoor facilities. To allow as much rainwater as possible to seep directly into the property, no other sealed area is used except for the roofs of the buildings, the entrance, as well as the car parking spaces, which are provided with a gravel surface. ‘The straw house is now one of the approximately 15 existing straw houses in South Tyrol’, comments the design group, ‘with already thousands of straw houses in Europe, and the trend is rising’.