Layered dry envelope insulated with sheep wool-lime mix

Energy efficiency in buildings is one of the main strategies to reduce environmental impact of the building sector. This goal can be obtained not only reducing energy demand for heating and cooling, but also, for example, improving envelope performances. On the other hand, the new approaches to energy efficient design are not only moving in the direction of lower and lower U-values to achieve lower energy consumption, but also the development and use of natural and local building materials. This paper describes the results of a research aimed to design and assess a new layered envelope component that might be implemented on buildings of the Mediterranean area in order to improve the energy efficiency and the environmental sustainability. The designed layered envelope system is composed by a layered core panel and two dry claddings. Two Oriented Strand Board panels, a waterproof sheet of Kraft Paper and a thermal insulating panel, in turn, compose the layered core panel, which could be also used as a partition wall or as a component of envelope walls, floors and roofs. An objective was to use natural and local materials to develop a new thermal insulating material from renewable resources with comparable building physics and mechanical properties to commonly used insulations materials. Among the available natural materials, sheep wool was chosen since it represents a waste and for its good behaviour with heat, moisture and indoor air pollution. Several sample have been realized mixing sheep wool, at different granulometry, with lime in different weight percentages; for each sample, thermal tests have been performed by means of a heat flow meter. The U value, Yie, the mass and the time lag have been evaluated for the whole designed system according to the Italian standards. The Life Cycle Assessment has been carried out to compare the environmental impact of the designed system with a similar traditional product. Finally, by means of the Ecotect software, the efficiency of the envelope was evaluated simulating the replacement of an old structure of a factory with the system designed for wall retrofit and for roofing. The results was good in terms of energy balances of the building, while one of the main issue of the LCA study was the lack of data for local materials.
Energy efficiency in buildings is one of the main strategies to reduce environmental impact of the building sector. This goal can be obtained not only reducing energy demand for heating and cooling, but also, for example, improving envelope performances. On the other hand, the new approaches to energy efficient design are not only moving in the direction of lower and lower U-values to achieve lower energy consumption, but also the development and use of natural and local building materials. This paper describes the results of a research aimed to design and assess a new layered envelope component that might be implemented on buildings of the Mediterranean area in order to improve the energy efficiency and the environmental sustainability. The designed layered envelope system is composed by a layered core panel and two dry claddings. Two Oriented Strand Board panels, a waterproof sheet of Kraft Paper and a thermal insulating panel, in turn, compose the layered core panel, which could be also used as a partition wall or as a component of envelope walls, floors and roofs. An objective was to use natural and local materials to develop a new thermal insulating material from renewable resources with comparable building physics and mechanical properties to commonly used insulations materials. Among the available natural materials, sheep wool was chosen since it represents a waste and for its good behaviour with heat, moisture and indoor air pollution. Several sample have been realized mixing sheep wool, at different granulometry, with lime in different weight percentages; for each sample, thermal tests have been performed by means of a heat flow meter. The U value, Yie, the mass and the time lag have been evaluated for the whole designed system according to the Italian standards. The Life Cycle Assessment has been carried out to compare the environmental impact of the designed system with a similar traditional product. Finally, by means of the Ecotect software, the efficiency of the envelope was evaluated simulating the replacement of an old structure of a factory with the system designed for wall retrofit and for roofing. The results was good in terms of energy balances of the building, while one of the main issue of the LCA study was the lack of data for local materials.