The „Nestwerk Pillnitz“ housing project began in 2000-01 as an idea of 9 self-organised families with a total of 39 members who wanted to build and live together in an ecologically sound manner. A site was found on a sunny south-facing slope near the Elbe and the park of the former royal palace in Pillnitz – an urban location yet in a green setting.
Two Passive Houses with a total of 9 apartments were constructed using ecologically sound materials and technology. Two buildings - each consisting of three terraced houses and three loft apartments were built around a shared tranquil atrium garden providing an ideal space for community life.
Every apartment also has an adjacent garden as private space. The apartments are sized from 52 m2 to 144 m2. Built with levels of different heights, the buildings follow the form of the slope. The ground floor is thus made up by a kitchen and a spacious living room comprising two levels with generous room heights. Bedrooms and bathroom are located in the upper stoery. The loft apartments are reached by covered stairs standing separately and extend over one level.
Decisions during planning stage as well as during the actual construction were reached in discussions involving the ownership community, the architects and the engineers. A main aim of the owners was to create an ecologically sound and healthy living environment. The energy consumption was to be minimised as much as possible without compromising quality of life. To achieve that, we used the low energy house concept in a more developed form.
The buildings were built in timber-frame construction with healthy building materials. The walls are constructed with “Doka” studwork (timber T profiles, at 1,28m centres) as well as oriented-strand-board which guarantees stiffeness and air tightness. The outer walls (three stories high) were made in one piece and then raised up to be subsequently attached to inner walls and floors, thus guaranteeing an air-tight façade. The walls were then insulated with cellulose (over a width of 37 cm) which is a product of recycled newspapers and achieves u=0,11 W/m2K.
The green roof was insulated with 34cm of cellulose (u=0,12 W/m2K). Deepened roof battens form the protruding eaves. Towards the partial basement (or ground level) the required energy conservation is achieved by crossing boards with an insulation of 30 cm. The total area of windows surface was reduced to 30 % to avoid overheating the buildings in summer. The wood windows have three pane energy- efficient glazing and insulated frames, which achieve u= 0,85 W/m2K and a g= 44% (only the timber of the cills is chemically treated). The materials to complete the structure were chosen to meet high ecological standards. Almost no chemical wood protection was used. Painting inside as well as outside was done using natural colour. Pigments joints were sealed with cotton wool and flaxes. Clay was added in places to enhance the timber construction. A green roof and rain water use complete the concept.
The elements of the energy concept are an automatic ventilation system with air heating in every apartment, solar panels (12m2) on every house with interim storage of a thousand litres and gas central heating. The legal division of the apartments and the individual floor layouts were accountable for the decision to instal separate ventilation systems (with attached ground heat exchanger) in each apartment. Additionally, a heated towel rail was installed in the bathrooms, as well as 3m2 of heating pipes embedded in the living room wall. These were installed solely for comfort, to allow the users to feel warmth on cold and unpleasant days.
The heating is distributed in insulated double pipe assemblies that are commonly employed in solar technology. The interim storage takes heating from both solar panels and the community gas boiler. The gas boiler with a performance of 36 kW was designed for warm water heating. The times required to heat up the water were considered. The total remaining required energy of both houses is 8 kW, calculated on the basis of PhPP. The remaining required heating energy of the apartments lies between 650W and 1600A. There are performance reserves for higher temperatures.
As per wish of some owners, a solution was to disconnect the master bedroom from the air circulation. To achieve this, the doors were completed with four sided sealing. The incoming air and the soundproofed overflow openings can be separately locked. Thus the room temperature can sink and an opened window at night does not cool the apartment.