The new nursing home was designed and constructed by Wolf Haus, a now global company founded in Burkardroth-Gefäll in the Upper Franconia region of Germany. Wolf Haus has been working on ecologically sound wood building techniques for over a hundred years. Today the company is in its fourth generation and, with over 90 employees working in production, construction and administration, it is one of the most well-known specialists in timber-frame construction housing. Buildings designed by the company include apartment buildings and houses for young families, as well as specialist accommodation, for example for students or the elderly.
The environment and sustainability are the company's top priorities and it therefore uses only kiln-dried wood from sustainable sources. "A timber house is an ecologically and modern high-tech product that complies with all the relevant DIN standards," says Frank Stanger, Domestic and International Sales Manager. "There is hardly any better material in terms of comfort, healthy living and aesthetics." Build times for timber-frame houses are also reduced to just a few months thanks to the construction method.
Timber frame requirements
The positive trend for timber-frame construction is continuing in house building in Germany. However, Frank Stanger believes, there is still great potential in the construction of public buildings, of which just ten percent are currently timber-frame. "This business area usually involves a number of complex regulations that must be adhered to, and this generally requires a high level of expertise."
Regulations for nursing homes
In Bad Bocklet, the timber-frame experts had to ensure that the specific building regulations for nursing homes were observed. The main concern was with the fire protection and sound-proofing concept. In collaboration with a local engineering firm, Wolf Haus developed a special concept, according to which, for example, all of the pipe work for the ventilation, electronics and heating had to be made from cast iron. The pipes, as well as all of the metal collars in the ventilation system, were also sealed and fire-proofed.
Increased fire protection requirements
It was first and foremost the increased fire protection requirements that led Wolf Haus to plank the 255 wall elements in the new nursing home, comprising wooden wall boards, both internally and externally, with "Rigidur H" fiberboard from Rigips. Rigidur H is the only type of gypsum fiberboard with a European Technical Approval (ETA) that also complies with the highest possible fire protection rating, A1, "not combustible", in accordance with European standard DIN EN 13501-1.
"In addition to its outstanding fire protection and structural performance, we were also impressed by the health and environmental properties of Rigidur H," explains Frank Stanger. Like the whole "Rigidur" range, Rigidur H is checked by its manufacturer, Rigips, for compliance with strict environmental criteria and is classed as an environmentally friendly building material. The IBR (Institute for environmentally friendly building, Rosenheim) has confirmed the ecological and healthy-living properties of the Rigips gypsum fiberboard range. All Rigidur products therefore bear the IBR seal of approval alongside the "A1" rating — confirming their status as ecologically recommended building materials.
The walls for the new nursing home were manufactured in the Wolf Haus factory. First the framing for the internal walls was built using timbers with a width of 120 or 160 mm; this was then planked with a double layer of Rigidur H on both sides. "For an F30 fire rating, one layer of planking using Rigidur H would have been adequate," says Frank Stanger. "However, we had to consider that a nursing home can sometimes be noisy. We decided on the double layer of planking in order to play it safe in terms of sound-proofing, and have therefore achieved a noticeable improvement in this respect."
The 160 mm framing was planked on the external walls with a 12.5 mm OSB on the outside and with Rigidur H on the inside. Windows and doors were cut in the external walls automatically using "Auto Cut". In the open spaces between the timber framing for the interior walls, the manufacturers inserted 60 mm-thick rock wool insulation; the spaces in the external wall frames were filled with 160 mm thick sheets.
Wooden ceiling construction
The ceilings in the building were constructed from wooden panels. "Wooden ceilings allow fast and easy production and eliminate the need for further sound-proofing," says Frank Stanger, explaining the choice of material. "It was also no extra effort for us to install the substructure for the acoustic ceiling using "Rigiton" perforated boards. The pipe clips for example were easy to fit, with no drilling or dowelling required. Using good wood screws, we were then able to easily install the different connecting elements." A concrete ceiling would have been considerably more costly and time-consuming.
Built in just six weeks
After the first eight weeks—during which time the floorboards and lift shaft for the two-storey building were installed—the entire building was constructed in just a further six weeks. The next step was to seal the roof, install the electrics, heating, sanitary facilities and ventilation system, and to complete the comprehensive dry-wall work.
At the same time the building was fully insulated, reinforced and plastered from the outside. Due to the high surface quality of Rigidur H, no filling work at all was required inside and it was possible to progress directly to painting or papering the walls. It took the Wolf Haus team just six months in total to carry out the foundation work, construction and finishing for the nursing home.
Energy consumption and heat loss
In terms of energy efficiency, the building complies with the KfW energy-efficient housing 40 standard, valid until April 1, 2009, and today, after the new German energy-savings regulations came into force, the KfW energy-efficient housing 50 standard — the building's heat loss due to transmission totals 0.27 W (m2/K). The annual primary energy consumption for the building totals 21.2 kWh/(m²a). "This means that we have achieved values well below the relevant upper limit values," emphasizes Frank Stanger. "And we have done so in a very environmentally friendly and economical way."
Saint-Gobain Rigips GmbH
Source: Quadriga 03/2010