Trustworthy partners in architecture can be worth their weight in gold, especially when the highest energy and aesthetic standards are sought. "With a well-rehearsed team collaborating over and over again, you can learn from each other and perfect the way you work," says Swedish civil engineer Ingrid Westman about the interdisciplinary approach on which her projects are based. Westman founded the construction company, Friendly Buildings AB in 2012. Together with Cage Copher's architectural firm Street Monkey Architects, as well as a team of engineers and a Polish module manufacturer, she has built two row house projects, five kindergartens, two single-family houses and a multi-family house in the past five years. The projects are all based on three principles: a high degree of prefabrication, the Passive House Standard and a design approach that does not compromise on the architect's original concept. Cage Copher considers the close cooperation to be ideal: "Usually architects in Sweden have little to no influence in the execution of their designs. The decision-making authority lies with the construction company and the client. A trusting relationship with the builder at least allows you to have some degree of influence."
Friendly Building acted as the property developer for its two terraced housing estates in Upplands Väsby and Örebro. From the acquisition of the land, planning and realisation to marketing, everything was managed in one. "Being our own client gave us the greatest freedom to realize our ideas," says Ingrid Westman. However, this also meant that Friendly Building had to bear the entire entrepreneurial risk. When asked about the surcharge that the buyers had to pay for the plus-energy standard, Westman responds: "What surcharge? In Sweden, you don't get a cent more for a passive house or plus-energy building. The only thing that counts when it comes to marketing is a good design and nice photos of the interiors. You may find it strange, but this is how the market works for us."
Individuality in series
The floor plans and construction of the 150 m² houses are the same in both locations, except for a few details. Only the facade materials and the roof design vary. In both cases, the structure consists of prefabricated, single-storey, steel framed modules with inserted reinforced concrete floors. The houses do not have a basement. The attics are unheated and uninsulated and consist of separate modules with different geometries depending on the location. In Örebro in particular, this strategy leads to a differentiated appearance: the housing estate consists of two L-shaped rows of houses. The six houses with north/south orientation have asymmetrical roof superstructures with inclinations of 25° and 37°. As the roof modules are alternately rotated by 180°, each house reads as a separate, independent unit.
In the other four houses, translucent gable linings made of highly perforated sheet steel emphasise the fact that the roofs are only technical structures. Originally the architects had conceived this design strategy for the project in Upplands Väsby in response to a neighbour's complaints about the excessive building height. In Sweden, height restrictions in zoning plans only apply to enclosed volumes, not to technical roof structures. The authorities however, did not accept the tactical strategy and the roofs had to be constructed at a lower incline. In Örebro, Street Monkey Architects managed to realise their idea after all - in this case, however, purely for design reasons.
The architects also combined three materials on the facades: white plaster, sheet steel standing-seam roofing and an additional wooden slat in order to create a separate "address" for each house. According to Cage Copher, this type of individualization is essential for marketing. Westman adds: "In Upplands Väsby, we initially offered the houses as zero-energy houses and met with no response whatsoever. As a result, we changed our marketing strategy and placed greater emphasis on design. After less than a week we had sold all the houses."
Up to 100 % difference in consumption
For ventilation, heating and hot water supply, each house has a compact unit that combines a MVHR system and a heat pump. The houses are heated solely by the supply air; while for freezing cold conditions there is electrically operated underfloor heating in the living room. All the kitchen units are pre-installed with energy-efficient household appliances. The solar systems on the roofs are jointly owned as is a stationary battery, which provides an additional 40 kWh of electricity storage capacity for the houses in Örebro. Together with the inverters, this battery is housed in a central technical room. Each house has an electricity meter, and all residents can view the electricity yield of photovoltaics and their own consumption via a website. Westman reports that the energy consumption of the inhabitants of otherwise identical houses and family sizes varies by up to 100 %. "Those who consume a lot sometimes call and complain because they think the measurements are wrong. Then we talk to each other and talk about their usage habits. Which room temperature do you prefer? How often and how long do they shower? Such details can make a huge difference."
In Westman's opinion, the scalability of the steel module construction speaks for itself. At the beginning of 2018, Friendly Building and Street Monkey Architects completed a 1200 m² kindergarten in Huddinge near Stockholm. In the same community they are currently building a school for 500 children. Of course, the grey energy would be lower in a timber construction," says Westman. “But it is more difficult to build tall buildings and larger spans with wood. At least this would have required a lot of development effort, which I could hardly have afforded with my small company.”
