Kindergarten and apartments - Chur, Switzerland

Calandastrasse 48/50

7000

Chur, Switzerland

Architect

Pfleger + Stöckli Architektur GmbH
Raetusstrasse 23, 7000 Chur
stoeckli@msarch.ch
+41 81 511 21 19

Owner

Chur municipality, Urban development office
Masanserstrasse 2, Postfach 820, 7001 Chur
Andrea.Rueedi@chur.ch
+41 81 254 47 76

User

Stadtschule Chur
Poststrasse 33, Postfach 810, 7001 Chur
stadtschule@chur.ch
+41 81 254 44 13

Contact Details

Dr Arch. Cristina Polo Lopez
SUPSI - University of applied sciences and arts of southern Switzerland
cristina.polo@supsi.ch
+41586666314

Other Information

Visits
Contact Stadtschule Chur

Related publications
Magazine TEC21, Magazine KultChur, presentation at a "exchange of experience", table presentation
Courtyard facade after renovation © Ralf Feiner, Malans
The building complex with a double kindergarten and two penthouses built in 1914 consumed 184,300 kWh/a before the renovation. Thanks to the good thermal insulation and the use of direct solar generation, the total energy requirement was reduced by 84% to 29,400 kWh/a. 79 m² of the latest generation of solar panels bring a lot of light and heat into the building. Inside there is enough mass to absorb the heat and store it above ground.
Energy performance
40 kWh/m2.y

Climate Zone Cfb

Altitude 592 m a.s.l.

HDD 171

CDD 14

Protection level Not listed

Conservation Area:
No

Level of Protection:

Building age 1900-1944

Year of last renovation:
2016

Building use Educational/Research

Secondary use:
Residential (urban)

Building occupancy:
Permanently occupied

Number of occupants/users:
30

Building area Net floor area [m²]: 703,0

Building typology:
Tenement/Kindergarten

Number of floors:
2

Basement yes/no:
Yes

Number of heated floors:
2

Gross floor area [m²]:
737,0

Thermal envelope area [m²]:
0,0

Volume [m³]:
3739,0

NFA calculation method:
SIA 416

Construction type
Brick masonry wall

External finish:
Plastered walls/exposed stone

Internal finish:
Plastered (on hard)

Roof type:
Pitched roof

+ MORE - LESS
Courtyard facade after renovation © Ralf Feiner, Malans
Courtyard facade after renovation © Ralf Feiner, Malans
Kindergarden © Ralf Feiner, Malans
Kindergarden © Ralf Feiner, Malans
Apartment © Ralf Feiner, Malans
Apartment © Ralf Feiner, Malans
Apartment © Ralf Feiner, Malans
Apartment © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Court © Ralf Feiner, Malans
Courtyard facade before intervention © City Chur
Courtyard facade before intervention © City Chur
Groun floor (storage area) before interventions © City Chur
Groun floor (storage area) before interventions © City Chur
Courtyard facade before intervention © P. Pfleger
Courtyard facade before intervention © P. Pfleger
Roof (non habitable)  before interventions © City Chur
Roof (non habitable) before interventions © City Chur
Roof (non habitable)  before interventions © City Chur
Roof (non habitable) before interventions © City Chur
Bathroom before intervention © City Chur
Bathroom before intervention © City Chur

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

Two new Kindergartens and two apartments have been designed to recovery an old public space located in Calandastrasse, in the city centre of Chur, Switzerland. The building benefits from its location directly on the open space of the neighbourhoods. This can be used by the kindergarten as well as by the tenants of the apartments as an outdoor space. The building presents also a private courtyard and can use it as a common outside space. To benefit lights and outdoor spaces, oversized dormers were created in the living rooms at the attic. This new building parts refer to the axes the arches of the courtyard and the existing Roof construction.
Urban context
On the neighbour area of the old artificial ice rink (KEB) on Calandastrasse in Chur, a new development with several apartment blocks has been implemented. A suitable replacement had to be created for the existing kindergarten by autumn 2015. The property at Calandastrasse 48/50, which is owned by the city of Chur, fulfils the requirements of the spatial program and is also suitable in terms of location and spatial qualities.

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION
Even if the building is not protected nor inserted in a conservation area, the owner (City of Chur) wanted to valorise the complex by making it a lighthouse for integration of energy saving and energy production in a refurbishment without demolishing the aspect. The heritage conservation was done from an urbanistic point of view more than form the choice of the construction details. In fact, the form, the shape and the walls of the building remains: the ensemble with the three-family house and especially the courtyard with the arch facade made of natural stone are the spatial parts worthy of preservation. Even the use of the building has been changed. Many old elements have been demolished and substituted with completely new elements (floor, roof, windows). The results show the integration of high technological element with the maintain of the urbanistic character.
Heritage Value Assesment
No heritage assessment

State of repair

Conditions of the envelope
The building was built 100 years ago according to the plans of the architects Schäfer & Risch as a residential and commercial building for the Beck brothers. The residential building is clearly characterized by a greater height and the facade design as the main volume of the ensemble. The adjoining building is deeper and, thanks to the L-shaped geometry, forms an inner courtyard which, with the round arches and the protruding roof, has a high spatial quality. Over the years, both buildings have been rebuilt and converted several times. These interventions have led to a "blurring" of the architectural expression.
Description of pre-intervention building services
In the basement of the neighbour house there was a gas central heating which was replaced in 2014 by a pellet heating. This supplied the house and the annex, including the apartments on the upper floor. The attic of the annex was not heated.

Aim of retrofit

Renovation
The city of Chur has been an energy city since 2011 and has set various priorities as part of the 2020 energy concept. The report - as of November 2010 - shows that there is great need for energy efficiency, especially in kindergartens.
Was there any change of use?
The ground storey turned to two Kindergarten spaces. The upper floor changed into two four-rooms apartments.
Lessons learned
The high-quality Heimatstil-ensemble has been preserved and upgraded in Chur, as a lighthouse in terms of renovation . A commendable example of how historical buildings can be adapted to the present day. The property was awarded the Swiss Solar Price 2016 for this reason.
Stakeholders Involvement
Public sector
Stadt Chur (Chur municipality)
Poststrasse 3
Andrea.Rueedi@chur.ch
Tel.+41 81 254 47 76
Architect
Pfleger + Stöckli Architektur GmbH
Raetusstrasse 23, 7000 Chur
stoeckli@msarch.ch
Tel.+41 81 511 21 19
Energy Consultant
Pfleger + Stöckli Architektur GmbH
Raetusstrasse 23, 7000 Chur
stoeckli@msarch.ch
Tel.+41 81 511 21 19
Structural Engineer
Hunger engineering
Ringstrasse 18, 7000 Chur
he@hunger-engineering.ch
Tel.081 250 39 39
Services Engineer
HT-Plan Haustechnik-Planungs AG
Haldensteinstrasse
info@ht-plan.ch
Tel.+41 81 284 69 69
Tools used
Was the renovation process done following a specific methodology? No
Energy calculation SIA 380/1
Hygrothermal assessment Qualitative assessment
Life Cycle Analysis (LCA) Qualitative analysis
Other No

RETROFIT SOLUTIONS

External Walls

Stone wall

Stone wall

The change in use of the commercial building required interventions that could guarantee habitability. To give a uniform and integrated appearance with the west apartment building, the original building volume was highlighted by dismantling the delivery ramp on the north side and restoring the old roof shape in the east wing. Compared to the previous situation, new openings have been created to have greater brightness and solar gains, partially changing the aesthetic aspect. The originally reserved north facade has been redesigned and upgraded through the new windows and the rear entrance.

Although there were no particular needs, the ensemble of buildings and especially the courtyard with the arch facade made of natural stone had were worthy of preservation. The choice of the materials was made following the principles of the building biology, for example open to diffusion (better conservation). The façade material is Multipor (mineral, cellular panel) with average thickness of 30 cm.

U-value (pre-intervention) [W/m2K]: 2,5 W/m²K U-value (post-intervention) [W/m2K]: 0,14 W/m²K
More Details
Original wall build-up
Plaster - Inside plaster:
20 mm
Stone - Wall is 200-400 mm thick, partially brick:
300 mm
Plaster - Outer plaster:
30 mm
Retrofitted wall build-up
Plaster - Inside plaster:
20mm
Stone - Wall is 200-400 mm thick, partially brick:
300 mm
Insulation - Multipor insulation:
300 mm
Plaster - Outer plaster:
10 mm


Windows

Wood metal window and triple-glazing with U-value 1.00 W/m2k

Wood metal window and triple-glazing with U-value 1.00 W/m2k

Compared to the previous situation, new openings have been created to have greater brightness and solar gains, partially changing the aesthetic aspect. The conversion is based on the principle of the solar direct profit house. Extensive calculations were carried out in the project planning phase for the implementation of this concept developed (master thesis). In order to get enough light and thus solar gains in the apartments, generous dormers were created in every second bulkhead. By moving on the opposite side, the roof space is optimally flooded with daylight. With a u-value of 0.41 W / m2K, the glasses on the north and east facade have a very good insulation value. A special solar glass with high energy transmittance (g-value) was used on the south and west facade. Therefore, the glasses have a u-value of 0.71 W / m2K.

Although there were no particular needs, the ensemble of buildings and especially the courtyard with the arch facade made of natural stone had were worthy of preservation.

Existing window U-value Glass [W/m2K]: 3,0 New window U-value Glass[W/m2K]: 0,71 Existing window U-value Frame [W/m2K]: 3,0 New window U-value Frame [W/m2K]: 1,0
More Details
Existing window type Casement window
Existing glazing type Double
Existing shading type Outer shutter
Approximate installation year 1980
New window type Casement window
New glazing type Triple
New shading type Mix of external blinds (apartments) and internal curtains (kindergarten)
New window solar factor g [-] 0,66

Other interventions

ROOF

GROUND FLOOR

OTHER

ROOF

The existing roof structure was left visible in the south wing. The roof in the east wing has been adapted and a new roof construction analogous to that in the south wing has been added. The roof structure was slightly modified to include the new dormers.

The project includes a roof design which is compatible with the architecture expression of the building. The materials are also integrated to maintain architectural relationship with the context. The insulation is insufflated cellulose (paper). As covering the old "beaver tail” tiles was reused.

U-value (pre-intervention) [W/m2K] 3 U-value (post-intervention) [W/m2K] 0.12
More Details
Original roof build-up
Tiles - "Beaver tail tile":
35 mm
Other - battens and counter battens:
90 mm
Other - wooden beams:
300 mm
Retrofitted roof build-up
Tiles - Reuse of the "Beaver tail tile":
35 mm
Other - battens and counter battens:
85 mm
Other - Wooden softboard:
60 mm
Other - Insulation: cellulose between the beams:
300 mm
Other - Panel from massive wood (Blockholzplatte, producer "Schuler"):
42 mm
GROUND FLOOR

The floors of the ground floor are partially against the ground and partially towards unheated rooms. The decision of the stakeholder was to excavate to receive a very good insulated floor. The thickness is variable, but goes up to 50 cm.

The project includes a floor design which is compatible with the architecture expression of the building. The materials are also integrated to maintain architectural relationship with the context.

U-value (pre-intervention) [W/m2K] 3.5 U-value (post-intervention) [W/m2K] 0.16
More Details
Original groundfloor build-up
Finish - Concrete:
80 mm
Concrete slab - Concrete:
250 mm
Retrofitted groundfloor build-up
Finish - Parquet floor:
10 mm
Other - Underlay concrete:
80 mm
Insulation - Impact sound insulation:
40 mm
Concrete slab - Concrete:
200 mm
Insulation - Foam glass gravel:
500 mm
Other - Lean concrete:
150 mm
OTHER

Specially constructed wooden ceilings were used as the primary storage elements. The closely arranged beams are aligned with the dimensions of the sand-lime bricks placed on them and increase the storage capacity four times compared to a smooth wooden ceiling. The ceiling of the Kindergarten had to be substituted to increase sound absorption, so the architectural proposal was to use special elements that also absorb heat. The Kindergarten profit clearly more than the Apartments of this technical solution.

The choice of materials is in line with the pre-existences.

HVAC

HEATING

VENTILATION

AIR CONDITIONING

DOMESTIC HOT WATER

HEATING

In the basement of the neighbour house there was a gas central heating which was replaced in 2014 by a pellet heating with a 1000 l accumulator. Additionally, 35m2 of thermal collectors for hot water and heating support were installed on the roof of the conversion, with a 4500 l accumulator. Pellet heating delivers the missing energy during the winter months.

The interventions for the heat production did not bring any particularly invasive interventions with the exception of the solar collectors on the roof (cfr. roof section).

More Details
New primary heating system New secondary heating system
New system type Boiler Solar
Fuel Pellets Solar
Distribuition system Radiators Radiators
Nominal power 22 kW 6 kW
VENTILATION

Decentralized ventilation monoblocks were installed in the kindergartens and decentralized comfort ventilation systems with heat recovery come in the new apartments. This enable operation with a high heat recovery factor that is adapted to the occupancy of the individual rooms. In summer, the devices of the kindergarten can also be used for night cooling. The ventilation decentral devices are installed in the bathrooms. Apartments: the ducts and vents are integrated in the roof. Kindergarten: the vents are in the walls of the bathrooms while the ducts are masked with a lowered ceiling.

The impact on the building has been reduced to a minimum with the choice of using decentralized appliances that do not require invasive conduct.

More Details
Original roof build-up New ventilation system
Type ventilation system Decentralized
Type flow regime Cascade
Heat recovery Yes
Humitidy recovery No
Nominal power 2.4 kW
Electric power 0,25 kW
Control system Integrated
AIR CONDITIONING

Decentralized ventilation monoblocks were installed in the kindergartens, which serve as night cooling in summer.

The interventions for the cooling did not bring any particularly invasive interventions with the exception of the solar collectors on the roof (cfr. roof section)

More Details
New cooling system
Type Decentralized ventilation elements
Distribuition system Air
Nominal power 2.4 kW
Electric power 0,25 kW
DOMESTIC HOT WATER

35m² of thermal collectors for hot water heating and heating support were installed on the roof of the conversion. The lack of energy is covered by the pellets system.

The interventions for the DHW did not bring any particularly invasive interventions with the exception of the solar collectors on the roof (cfr. roof section)

More Details
New DHW system
Type RES
Hot_water_tank Yes
With heat recovery No

RENEWABLE ENERGY SYSTEMS

SolarThermal

Photovoltaic

Biomass

SolarThermal

35m² of thermal collectors for hot water and heating support were installed on the roof of the conversion. The final yield of reach approximately 21'000kWh per year. The yield covers the demand of about 19'000 kWh of the reconstruction by far, even a high surplus is balanced, but in the winter months the coverage is not sufficient. The surplus is transferred to the attached 3-family house at Calandastrasse 48. In return, the CO2-neutral pellet heating system, which will be installed in 2014, will provide the missing heat for the conversion during the winter months. The aim is to achieve an annual balance between exports and imports. BIPV and ST plants covers 95% of energy demand (NZEB). The project was awarded with the Swiss Solar Prize Diploma 2016 - Category B, Buildings: renovations.

The solar thermal system complies with many of the geometric and spatial and construction compatibility criteria required by current regulations for the integration of solar systems in historic buildings (grouping, coplanarity with the roof slope, respect for the eaves lines and roof edge, joint precision, etc.). The aesthetic, material and colour compatibility with the existing roof is not optimal, but the final result is good and well integrated with other new elements incorporated in the renovation of the building such as the dormers.

Solar thermal system is integrated in the top of the roof in the south-west slope, in the internal courtyard of the building, with a uniform appearance similar to the photovoltaic system integrated in the building.

More Details
SolarThermal System
Type Flat collector
Collector area 36,0 m²
Elevation angle 38,0
Azimuth 162,0
Overall yearly production 20958,0 kWh
Heating_contribuition 12611,0 kWh
DHW contribuition 6576,0 kWh
Cooling contribuition 0,0 kWh
Photovoltaic

The 8.6 kW strong and 54 m² large BIPV system, which is optically well integrated but not over the entire surface, generates 9,000 kWh/y of solar power. BIPV and ST plants covers 95% of energy demand (NZEB). The project was awarded with the Swiss Solar Prize Diploma 2016 - Category B, Buildings: renovations

Solar photovoltaic system is integrated in the top of the roof in the south-west slope, in the internal courtyard of the building, with a uniform appearance similar to the solar thermal system integrated in the building. The system complies with many of the geometric and spatial and construction compatibility criteria required by current regulations for the integration of solar systems in historic buildings (grouping, coplanarity with the roof slope respect for the eaves lines and roof edge, joint precision, etc.). The aesthetic, material and colour compatibility with the existing roof is not optimal, but the final result is good and well integrated with other new elements incorporated in the renovation of the building such as the dormers.

With the energetic renovation and an innovative heat network concept with the adjoining apartment building (MFH) with three families, the city of Chur is paving the way for the energy transition. There is a combined PV and thermal system on the roof. It covers its own energy requirements with 28,300 kWh / a to 95%. The solar excess heat of around 9,100 kWh / a, which cannot be used in the transition period and in summer, is delivered to the neighbouring MFH. In the winter half-year, the pellet heating of the neighbouring MFH supplies the kindergartens and penthouses with 8,800 kWh of heat.

More Details
Photovoltaic System
Type Monocrystaline
Collector area 54,0 m²
Total nominal power 8,6 kW
Elevation angle 38,0
Azimuth 252,0
Overall yearly production 8983,0 kWh
Heating contribuition 0,0 kW
DHW contribuition 0,0 kW
Cooling contribuition 0,0 kW
Lighting contribuition 8620,0 kW
Biomass

In the basement of the neighbour house there was a gas central heating which was replaced in 2014 by a pellet heating. This supplied the house and the annex, including the apartments on the upper floor.

The interventions for the heat production did not bring any particularly invasive interventions. The neighbour house is protected and this renovation didn't touch it.

The heating did replace an existing old one

More Details
Biomass System
Type Pellet
Storage size 1000
Origin of biomass Region Graubünden
Overall yearly production 8800,0 kWh

Energy Efficiency

Energy Performance
Energy performance certificate: No
Voluntary certificates: No
Energy Use
Heating
Consumption_estimation_Calculation_method: Steady state simulation (e.g. EPC, PHPP)
Documents:
g-16-09-22_dwhg_und_doppelkindergarten_chur_def[1].jpg
Swiss solar prize fact-sheet, Solar Agentur Schweiz
Pagine da KIGA_150916_A3_4.jpg
Energy concept, fact-sheet, Pfleger + Stöckli Architektur GmbH

Consumption_estimation_Before: 250 kWh/m2.y
Consumption_estimation_After: 40 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: Steady state simulation (e.g. EPC, PHPP)
Documents:
Dati energetici Chur.jpg
Energetic calculation

Consumption_estimation_Including_DHW: Yes
Consumption_estimation_Before: 310 kWh/m2.y
Consumption_estimation_After: 75 kWh/m2.y
Measured Parameters
Internal Climate
Type_of_monitoring: Punctual
Description: The indoor climate is optimized by materials that are open to diffusion and according to building biology and mechanical, CO2-controlled ventilation.

External Climate
Type_of_monitoring: Punctual
Description: Only the standard values of the climatic station.

Construction
Type_of_monitoring: Punctual
Description: Ordinary architectural monitoring: the project manager of the architectural office did his master thesis (sustainable building) on the property. The acoustics are solved with additional mass for heat storage.

Internal Climate

Temperature

Temperature control with sensors for the different uses

Indoor Air Quality

The indoor climate is optimized by materials that are open to diffusion and according to building biology and mechanical, CO2-controlled ventilation (decentralised monoblock).

Daylight

Natural lighting has been improved with more generous openings that allow the entry of more natural light, as shown by the various photographs, in particular with the dormers on the roof floor and with the front of the windows with arches towards the courtyard.

Acoustic Comfort

The acoustics are solved with additional mass for heat storage.

Artifact Conservation

-

Costs

Financial Aspects

The intervention was promoted and implemented by the city of Chur, which has set itself very advanced energy objectives as it is an "energy city". The costs of the below listed below contain everything necessary.

Investment Costs
Total investment costs
3,460,000 CHF (total)
Amount includes: Includes positions 0, 1, 2, 4, 5 and 9 of Building Cost Classification, namely: site, preparatory works, building, eternal works, incidental costs and provisional items, furnishing

Cost of energy related interventions:
1'040'000 CHF (total)
Amount includes: Roof, Insulation floor, Windows/doors, Wall insulation, Heating (distribution), Ventilation/clima, Solar (PV and STh)
Running Costs
Lifecycle cost
No

Environment

Greenhouse Gas Emissions
Methodology_used: SIA 2013: 2009 Energy certificate
Documents:
Pagine da Reporting Overview Kindergarten Calanda - EnerCoach.jpg
Reporting Overview Kindergarten Calanda - EnerCoach

emissions_at_use_stage_before_intervention: NA NA
emissions_at_use_stage_after_intervention: 1 kg per m2
emissions_before_use: NA
Building_Lifetime: 25
Transport and Mobility

Reduced number of parking spaces, very close to the center. The children are from the surrounding area and come by feet.

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