PHBdW: Passivhaus Bau der Woche 13

The corten rainscreen of this stunning house in Ulm (home of Max Bill’s Ulmer hocker – a brute force fave) has been a post in waiting since the moment we laid eyes on it. Sporting blind fasteners and open joints is definitely a preferable appearance and coordinating joints with fenestration is always a plus in our book. The rainscreen features a specially developed aluminum and stainless steel substructure. Best guess on the stainless steel is to reduce thermal bridging at envelope penetrations. While being certified as a Passivhaus ensures significant lifetime energy reductions – on some level we hope the steel had a high recycled content to keep the PEI/CO2 emissions down.

This house is incredibly open – the only room on the ground floor that closes off is a guest room. Walls delineating space are not coplanar – allowing for constantly shifting perspectives. The kitchen is definitely the heart of this house and is not lacking in quality. We especially think the island and bench are incredible. The upstairs features an open bathing area.

One aspect to this house that really stands out to us is the mechanical room – located on the second floor. This changes the game a bit – instead of trying to hide the HRV exhaust and supply or ‘celebrate’ them on the façade (a tactic that usually fails) – they can vent straight up out of the roof. Clean, efficient – definitely works for us.

Airtightness: 0.29ACH50
Heating Demand: 13 kWh/m²a (4.44kBTU/ft²a)
Primary Energy Demand: 119 kWh/m²a (37.7 kBTU/ft²a)
U-value=0.74 W/m²k (R-7.7)
Glazing: SGG climatop Solar Krypton Ug=0,6 W/m²k (R-9.5), SHGC = 0.57
Above-grade wall assembly,
U-value=0.108 W/m²k (R-52)

  • Plaster
  • Reinforced concrete/ clay block
  • 30cm (12”) exterior insulation (mineral wool)
  • WRB
  • Air space
  • 4mm corten steel rainscreen on aluminum framing

Ground slab assembly, U-value=0.095 W/m²k (R-60)

  • Wood flooring
  • screed
  • 6 cm insulation
  • Concrete slab
  • 30 cm (12”) XPS

Roof assembly, U-value=0.097 W/m²k (R-59)

  • Plastered GWB
  • Concrete deck
  • 35cm (14”) insulation
  • Bituminous roofing
  • green roof

This house exemplifies the Brute Force approved approach to an optimized Passivhaus (without ridiculously thick envelope):  a compact volume, ample high SHGC glazing to the south, exterior shading to protect against overheating and a well detailed envelope. Add in a few skylights (blasphemy!), a beautiful corten guardrail and some minimal detailing – and you’ve the making for a contemplative, comfortable and incredible modern home.

  • Architect: mühlich fink + partner
  • Location: Ulm (DE)
  • TFA: 230 m² (2,476 ft²)
  • building costs: €1,045/ m² ($110/ft²)
  • completed: 2003
  • fotos: Martin Duckeck | Victor Brigola

additional links:

  • Passivhaus datenbank entry
  • schoener wohnen article (pdf)
  • architektur + technik article (pdf, german)
  • John Semmelhack

    “This house exemplifies the Brute Force approved approach to an optimized Passivhaus (without ridiculously thick envelope)”.

    How does R-60 slab insulation make sense when walls and roof are slightly less? Did hell freeze over in Germany (causing really cold ground temperatures)?

  • mike eliason

    Good question, John. We’ve been noticing most EU envelopes tend to be somewhat even around the whole building.

    For this house, there may have been a number of reasons – thicker envelope would have meant pricier components to build the rainscreen, adding insulation (thickness) to the roof may have been seen as an aesthetic compromise…

    However, after delving into PHPP, my guess would be related to ground temps being lower in Germany due to less solar radiation. In most of the US climates, ground temps exceed 68/70F at some point in the year and stay slightly warmer into fall/winter. In Germany, it’s rare to get above 63F and fall/winter temps decline faster. I think this means there would be significantly more heat loss later in the year through the ground than most US cities.

    So in a sense, you might be right.

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