Timber-frame terraced Passive Houses in Darmstadt

On the occasion of the upcoming Conference on the Passive House, I would like to write about the German architect Georg Zielke, who will lead the Open Forum “Passive House: an ingenious concept! Where is the demand? “.

Georg Zielke is an independent architect with many years of experience in environmental and economic planning for housing. His office is in Darmstadt, Germany. Since 2002 he specializes in the planning and construction of residential buildings with the passive house standard.

His main interests and competences are:

  • Construction of cost-effective and environmentally friendly housing projects
  • Use of ecological building materials
  • Development and reconstruction of existing properties
  • Standardized building design
  • Use of recyclable materials

On my last trip to Darmstadt, I visited a housing complex of seven terraced houses in Kranichstein, planned and realized by Georg Zielke.

These residential units, standing at least 30 cm above the ground, were planned and erected with prefabricated timber panels. The timber-frame construction was built on self-made cellars (concrete shuttering blocks) which were placed and were ready for construction within 4 weeks. Due to 30 cm thick insulation the house is heated by the warmth emitted by sun light, people and appliances.

The floor plans were designed individually according to the client’s wishes. Each house has a ventilation system with heat recovery. The fresh air coming into the homes through an insulated duct that passes through the heat exchanger core where it gets heated up by the outgoing stale air, which is collected from the bathrooms, kitchen and sometimes utility or laundry room. After it is heated, the fresh air is ducted throughout the living areas and bedrooms. Stale air is pulled from the home and enters the other side of the core where its heat is given to the fresh air, before it is exhausted from the building via ductwork. The heating and hot water are supplied via a district heating system (DHN).

The facades were clad with untreated, rough sawed larch wood. The vertical timber cladding is structured with colored aluminum panels – a different color is assigned to each house. (The aging processes may and should be visible: The older the house gets, the more silvery the larch boards become and the more colorful the panels appear. This effect is starting to be visible after about 10 years. The blinds integrated in the facade provide summer protection against overheating. The indoor climate is therefore extremely comfortable in both summer and winter.

Selected project details:

  • energy-efficient construction
    (30cm exterior insulation, ventilation system with heat recovery,  airtightness, thermal bridge free)
  • rainwater utilization system
  • ecological building materials
    Timber construction: Great importance was given to the wood protection. Chemical wood preservation was deliberately avoided.
  • green roofs

The site was completed in 2015, including the roads and green areas. Planning and building at the site took more than 10 years in total. An essential feature of the area is the reduction of car traffic. The quarter was designed car free and is very well connected to the public transport system of Darmstadt with a newly built tram.