From last January in the roman neighbourhood of Quadraro the building site of the first urban straw bale house in Italy was declared open. The house, designed by the BAG Offinamobile team led by architect Paolo Robazza, has a timber frame structure and straw bale walls.
The designers have a distinctive approach to the building for two reasons: the first and more obvious is the materials choice, for example the chosen plaster is a mix of local dirt and crushed bricks and is a modern reinterpretation of the traditional roman vernacular architecture; secondly is the choice of establishing a shared building site, i.e. a site where young professionals are invited to take part of the actual building.
The result is a natural and extremely breathable building, boasting very high thermal efficiency thanks to the straw that gives freshness to the interiors in summer and cosiness in wintertime, avoiding humidity. All this considerably affects the costs for winter heating so the potential saving goes up to 75% compared to a conventional house.
In 2002 building laws reduced the residential K value for external walls to 0.35 W/mqk. A non-plastered straw bale, thanks to its thickness of 450mm, has a K value of 0.13 W/mqk, so that its thermal performance is much higher than the required one. Furthermore with the plaster its K value is even lower.
Paolo Robazza, who has worked at the EVA project in l’Aquila, reminds us of an additional important feature of his project concerning the materials supply is from local producers, cutting down on CO2 emissions and transportation costs.