B.G. Hellers

Emeritus Professor of Building Engineering, School of Architecture and the Built Environment, The Royal Institute of Technology (KTH), Stockholm, Sweden; bogoran@arch.kth.se

ABSTRACT

Masonry was the most common material used in construction in ubran areas in Sweden for a long time. It was not until the 1920s that reinforced concrete became widely used. A combination of materials became common in multi-family housing and, in some cases, also in single-family housing; floor slabs were made of concrete, walls were made of brick masonry and roof structures were constructed of wood. A late example of such houses has been the topic of the author’s recent technical contribution in rebuilding economical structures for modern living. The project serves as an example of modernizing with a sense of proportion. The house is a twostorey structure constructed between 1959 and 1961, by the Swedish architect Folke Hedérus, “the most talented architect of his generation”. The house, situated on Lidingö, an insular community close to Stockholm, has a living area of some 300 m². The roof, originally being flat, its edges are now lifted from 140 to 340 mm to allow for an increase of mineral wool insulation, and have an inward inclination towards a runway with only two outlets (originally three). The vertical storm water piping was increased from 120 to 150 mm for compensation. The large thin glasses windows of the façade are replaced by modern glass panes, lowering the heat transmission factor from 2.6 to 1.1 W/m² K. The insulation of wooden parts of the second floor is doubled from 100 to 200 mm of mineral wool. The concrete floor of the lower storey, originally un-insulated, was covered with 100 mm cellular plastic, glued upwards. Brick walls were however not modified. In total, the heat losses from the vertical parts were halved. In addition, and most important, the ventilation and heating systems were separated by replacing circulating hot air with water circuits on each floor.

KEYWORDS: brick masonry, floor heating, heat insulation, rehabilitation, slopes

B5-5