The house’s climate shell, part 2 – insulation, foundation and roof

In my previous text about the house’s climate shell I described the building’s structure. However, it’s not enough to simply have a good wall that features several layers of insulation – the insulation also has to be of high quality. The façade cladding and thermal insulation come from Isover, which supplied its most energy-saving insulating materials. The roof too features better than normal insulation. These materials are packed somewhat harder to increase their density, thus improving their thermal capability. The roof consists of a glued laminated timber beam that is eight metres long, 80 centimetres thick and 12 centimetres wide. This beam carries a number of joists that span the structure from the middle of the beam out towards the outer edges. We use this building method instead of traditional roof trusses to get extra volume to the rooms on the upper floor.

The foundation is a vital part of any house. In the case of the Lindell family’s house, it is built on a very special foundation that fulfils several functions:

1) It has to insulate the house from the ground
This is achieved with a 300 mm thick layer of Styrofoam that is inserted below the concrete. In the same way, the building’s edge beam, which supports the walls, is also insulated so it does not come into contact with the interior floor. This solution avoids the risk of thermal bridges via the floor.

2) It has to warm the house
The foundation integrates one of the building’s heating systems. It is a low-temperature waterborne floor heating system that has been installed to meet the Lindells’ comfort requirements and give them a pleasant indoor climate.

3) It has to be environmentally friendly
This is a difficult issue since the foundation is made of concrete. Wood is a construction material that is about 10 times more environmentally friendly than concrete, which means that the foundation accounts for a relatively large proportion of the building’s carbon dioxide footprint. In order to minimise the environmental impact of the foundation, we have reduced the amount of concrete in the foundation from the traditional 10 centimetres thickness to 8 cm.

Christian Axelsson, A-hus