Kohlerhaus

Färbergasse 3

39038

Inninchen - San Candido, Italia

Owner

Different owners

architetto

Hansjörg Plattner
Via Delai Straße 4 Bolzano
info@plattner.bz.it
+39 0471 972912

Contact Details

Eleonora Leonardi
Eurac Research
eleonora.leonardi@eurac.edu

Other Information

Related publications
Book: ein Haus in Innichen - una casa a San Candido, Hans Jörg Plattner with contribution of Martin Mittermair
© Eurac
The Kohlerhaus, a building dating back to the 14th century, was renovated to accommodate 10 apartments with the high standards of comfort and efficiency. The historical research carried out by the architect revealed the rich past of the building, that served as priest house, hotel or guest house. The retrofit of the building included external insulation the wall with reed mats, new replica windows and new building services (radiating heating and mechanical ventilation).
Energy performance
68,28 kWh/m2.y

Climate Zone Dfc

Altitude 1175 s.l.m.

HDD 2922

CDD 15

Protection level Not listed

Conservation Area:
Si

Level of Protection:
Ensembleschutz (ensemble protection) South Tyrol: for more information see http://www.provincia.bz.it/natura-ambiente/natura-territorio/costruire/tutela-insiemi.asp

Building age before 1600

Year of last renovation:
2011

Year of previous renovation:
1980

Building use Residential (urban)

Secondary use:
NA

Building occupancy:
Discontinuous occupancy (i.e. holiday home)

Number of occupants/users:
28

Building area Net floor area [m²]: 195,0

Building typology:
Detached house

Number of floors:
4

Basement yes/no:
Si

Number of heated floors:
4

Gross floor area [m²]:
275,0

Thermal envelope area [m²]:
1451,0

Volume [m³]:
3300,0

NFA calculation method:
Useful area (it)

Construction type
Stone masonry wall

External finish:
Rendered

Internal finish:
Plastered (on substructure)

Roof type:
Pitched roof

+ MORE - LESS
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus in a historic postcard
Kohlerhaus in a historic postcard
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Kohlerhaus after renovation © Büro Plattner
Building before intervention © Büro Plattner
Building before intervention © Büro Plattner
Building during intervention © Büro Plattner
Building during intervention © Büro Plattner
Inside conditions pre intervention © Büro Plattner
Inside conditions pre intervention © Büro Plattner
Inside condition after floor demolition © Büro Plattner
Inside condition after floor demolition © Büro Plattner

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

The Kohlerhaus has a long history, which begins in the 14th century. It was built as a chapter house, it was about 7*7 in size. In 1784 it was rebuilt as priest's house and got its present size. In 1803 Mr. Koll (later Kohler) bought the house by auction. The house will then see different owners and different uses (hotel annex, guest house, residential house). In 1980 a partial renovation was done in order to get livable one flat in the first floor. A fundamental restoration began in 2010, which was initially intended to give the house back its early 20th century appearance. In the course of the work, the remains of the old core came to light and slowly the history of the house became visible through building and archive research. The architect wanted to discover how the house looked like in 1784 and then bring the house back to his original aspect. In order to finance the work, 9 of the 10 apartments were sold, 8 as vacation apartments, one is permanently occupied.

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION
The elements that are worthy of preservation are the external walls and some windows.
Heritage Value Assesment
The building's heritage value is connected to its history and age.The cellar is dated 14th century, the rest of the house goes back to 1784. The house is not listed also because the heritage authority was convinced that the house was dated beginning 20th century. A long research done by the architect revealed that the history of the house actually began much earlier.
Heritage Assessment Files
Historic postcard (191)
Historic postcard (191)
Historic photo (191)
Historic photo (191)
Photo 1970
Photo 1970

State of repair

Conditions of the envelope
The building was in a bad condition. Only the first floor was renovated to a flat in 1980. The renovation included internal works and external insulation.
Description of pre-intervention building services
In the first floor radiators with an oil boiler were installed with the renovation of 1980. In the rest of the house there were no building services.

Aim of retrofit

Renovation
The main aim of the retrofit was to get the building livable. The initial aim was also to maintain the original aspect of the building that was thought to be the one of 1925 (there is a postcard with a photo of the building). The fact that this is a historically valuable building with a core from the 14th century only became apparent during the construction work. During the renovation, the architect carried out literature studies and reconstructed the history and then adapted it to the project. To restore externally the house to its original appearance of 1784 and to respect the original materials were the new aims. The architect wanted to bring the house to Klimahouse B standard (heating demand lower than 50kWh/m²y). In San Candido it is highly appreciated that an old building has been renovated and its history reappraised and that old cultural assets are preserved and lived again.
Was there any change of use?
Over the centuries, different uses have alternated. Born as chapter house was rebuilt as priest's house, and after alternated the uses of hotel annex, guest house, residential house. With the last renovation, ten apartments were built. One is permanently occupied and the other nine are holiday apartments.
Stakeholders Involvement
Architect
Hansjörg Plattner
Via Delai Straße 4 Bolzano
info@plattner.bz.it
Tel.+39 0471 972912
Structural Engineer
Dr. Ing. Günther Rauch Planpunkt GmbH
Handwerkerstraße Süd 1. 39044 Neumarkt
info@planpunkt.net
Tel.+39 0471 81 15 11
Services Engineer
Dr. Erwin Mumelter
Beda Weber Straße 1, 39100 Bozen
Other
Per. ind. Meinhard von Lutz
Frag 12, 39043 Klausen
Tools used
Was the renovation process done following a specific methodology? No
Energy calculation Klimahaus
Hygrothermal assessment No hygrothermal assessment was done
Life Cycle Analysis (LCA) No Life Cycle Analysis was done

RETROFIT SOLUTIONS

External Walls

Existing stone wall

Wall Veranda

Existing stone wall

The stone wall was insulated from the outside and from the inside with reed insulation. On the outside 12 cm of reed insulation and on the inside 2 cm with clay plaster were installed. Only in the ground floor wall heating system is installed. This due to two reasons: the absence of niches in the ground floor (present instead in the upper floors) makes it difficult to position the radiators; the wall heating system helps in case of rising damp. The architect originally thought of insulation in mineral foam. Then he noticed that with that the details (transitions to wooden windows) are not so easy to solve. Furthermore he wanted a material that respect the original natural stone wall and decided to use reed mats after he got to know a company that was using it.

The architect chose to use reed insulation for its compatibility with the existing wall: reed mat is a natural material and according to the architect this is a way to respect the existing wall. The facade is plastered to restore the external aspect to the original aspect.

U-value (pre-intervention) [W/m2K]: 2,0 W/m²K U-value (post-intervention) [W/m2K]: 0,33 W/m²K
More Details
Original wall build-up
Plaster :
20 mm
Render - Stone mansory wall:
600 mm
Plaster :
20 mm
Retrofitted wall build-up
Plaster - On the outside a thermal plaster was applied (λ=0.057 W/mK)).:
30mm
Insulation - Reed Insulation:
119 mm
Stone - Existing stone mansory wall:
600 mm
Insulation - Reed mat with heating system:
32 mm
Plaster - A clay plaster was applied internally, to improve the indoor climate.:
15 mm
Wall Veranda

The wall of the veranda was built up new because the old one had bad conditions. The veranda is dated 1895 and consisted only of a timber structure. The two columns supporting the veranda have been maintained and the form of the veranda was changed with the renovation.

For this solution, the architect wanted to rebuild the veranda paying attention on its external aspect.

U-value (pre-intervention) [W/m2K]: 2,3 W/m²K U-value (post-intervention) [W/m2K]: 0,27 W/m²K
More Details
Original wall build-up
Wood - Wood thin layer:
30 mm
Retrofitted wall build-up
Wood panelling :
30mm
Other - DWD Agepan:
15 mm
Insulation - Wood Fiber with Wood Structure:
160 mm
Other - OSB panels:
19 mm
Plaster :
15 mm


Windows

Box type windows

Box type windows

The existing box type windows had been already replaced in the last years. The architect wanted to have an energy efficient replica of the original box type windows. The window size was kept the same everywhere, apart from few windows that had to be bigger for building law reason.

The windows have been replaced with an energy efficient replica. The new external window consist of a single glazing with the original form of the frame and it is without sealing. The new internal window consists of a double glazing with a new frame and is sealed.

Existing window U-value Glass [W/m2K]: 3,0 New window U-value Glass[W/m2K]: 1,2 Existing window U-value Frame [W/m2K]: 2,0 New window U-value Frame [W/m2K]: 1,8
More Details
Existing window type Box-type window
Existing glazing type Single
Existing shading type Outer shutter
Approximate installation year 1980
New window type Box-type window
New glazing type Single glazing for the external window and double glazing for the internal window
New shading type Outer shutter
New window solar factor g [-] 0,62

Other interventions

ROOF

GROUND FLOOR

MEASURES TO INCREASE AIRTIGHTNESS

ROOF

The existing wooden structure of the roof was kept. Some damaged existing beams were replaced and some additional beams were installed. The existing cover was not the original one, it was installed after a fire happened in 1985; in the old photos the roof is a plate with rhomboid-shaped muster. The decision of the architect was to get the roof looking similar to the old roof, that is why a new plate was installed.

The existing roof cover was modern and not the original one. The wish of the architect was to get the cover looking as the early 20th century cover, thus a replica was applied. The structure of the roof was kept and just reinforced.

U-value (pre-intervention) [W/m2K] 2.3 U-value (post-intervention) [W/m2K] 0.19
More Details
Original roof build-up
Metal sheets :
5 mm
Other - wooden boards:
30 mm
Other - Wooden beams:
240 mm
Other - None:
0 mm
Retrofitted roof build-up
Metal sheets :
5 mm
Other - ventilation layer:
50 mm
Other - OSB plate:
20 mm
Other - wood fiber between the beams:
240 mm
Other - OSB plates:
20 mm
Other - Plaster:
15 mm
GROUND FLOOR

Part of the building has a cellar, in this part no renovation measures were done. In the other part, the ground floor was renovated with insulation above the screed which was installed in 1980.

The ground floor has no elements worthy to preserve because it was renovated in 1980.

U-value (pre-intervention) [W/m2K] 3 U-value (post-intervention) [W/m2K] 1.1
More Details
Original groundfloor build-up
Finish - different pavements:
20 mm
Concrete slab :
200 mm
Retrofitted groundfloor build-up
Insulation - foam glass:
50 mm
Concrete slab :
200 mm
MEASURES TO INCREASE AIRTIGHTNESS

Attention was paid to the joints walls-roof and walls- windows

HVAC

HEATING

VENTILATION

DOMESTIC HOT WATER

HEATING

The building is connected to the local district heating system. In the ground floor, a wall heating system is installed while radiators are installed in the other building stocks, using the existing niches under the windows.

The radiators were installed in the existing niches under the windows. In the ground floor there isn't any niche, thus there a wall heating system was built.

More Details
New primary heating system
New system type district heating
Fuel Biomass
Distribuition system Combination of wall heating (ground floor) and radiators (other floors)
Nominal power kW
VENTILATION

30 ventilation units were installed. They provide supply air and they take extract air directly in each room where they are installed, so a connection with pipes between the rooms is not needed. The devices are installed in the sleeping rooms and in the living rooms. The ambient air and exhaust air vents are integrated in the window embrasure.

The reasons that made this solution compatible with historic buildings are two. The system is a room by room system and this allows to avoid air pipes installation. The ambient and exhaust air vents are integrated in the window embrasure. The facade is not touched and the vents are hardly visible.

More Details
Original roof build-up New ventilation system
Type ventilation system Room-by-room
Type flow regime The system is room by room that means in each room there is supply air and abluft.
Heat recovery Si
Humitidy recovery No
Nominal power 55 kW
Electric power 55,0 kW
Control system
DOMESTIC HOT WATER

The domestic hot water is provided with the district heating

More Details
New DHW system
Type with heating system
Hot_water_tank No
With heat recovery No

Energy Efficiency

Energy Performance
Energy performance certificate: The building has the Klima House certification. This certification is compulsory in South Tyrol.
Voluntary certificates: No
Energy Use
Heating
Primary Energy 16,9 kWh/m2.y
Documents:
KH_Zertifikat.pdf
Consumption_estimation_After: 68,28 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: Steady state simulation (e.g. EPC, PHPP)
Documents:
KH_Zertifikat_1.pdf
Consumption_estimation_Including_DHW: Si
Consumption_estimation_After: 16,9 kWh/m2.y
Measured Parameters
Internal Climate
Type_of_monitoring: Continuous
Description: Inside the building the temperature, relative humidity and the CO2 level are monitored in the sleeping room and in the living room inside two flats.

External Climate
Type_of_monitoring: Continuous
Description: The outside temperature and humidity is monitored.

Construction
Type_of_monitoring: Continuous
Description: Temperature and Humidity are monitored between external insulation and stone wall, within the stone wall, between internal insulation and stone wall. The internal surface and external surface temperature are also monitored.

UserBehavior
Type_of_monitoring: Continuous
Description: The opening of some windows in the living room of two flats are monitored. Additionally, the energetic consumption is monitored.

Internal Climate

Temperature

A positive feedback regarding the temperature was delivered from the users for winter and summer. The building does not need a cooling system due to its position and altitude.

Indoor Air Quality

A good indoor air quality is guaranteed from the ventilation system. The users are satisfied with it.

Daylight

The window opens of the building are quite tight, as it is in the majority of the historic alpine buildings. Thus, the daylight can not be the same as in a new construction. To meet the daylight criteria few openings have been enlarged. The users were aware of this and nobody complained.

Acoustic Comfort

The building is well insulated from outside, also thanks to the box type windows. Between the apartments sound insulation was installed. Impact sound measurements were done with good results. The users are very satisfied with the acoustic comfort.

Artifact Conservation

There are no artifacts in the building.

Costs

Financial Aspects

The size of the building and its state before it was renovated led to very high renovation costs. 9 of the 10 apartments of the building were sold. The costs were higher than a normal refurbishment, due to the attention payed to the conservation.

Running Costs
Annual heating cost
We do not have information about the costs. The annual energy consumption of a flat is monitored and corrisponds to 97,75 kWh/m²a. (per m2)

Nel rispetto del regolamento (UE) 2016/679, ti informiamo che questo sito utilizza cookie propri tecnici e di terze parti per consentirti una migliore navigazione ed un corretto funzionamento delle pagine web. Proseguendo la navigazione del sito o cliccando su "OK" acconsenti all'uso dei cookie. Se vuoi saperne di più o negare il consenso, clicci qui.