GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Doragno Castle - Rovio, Ticino, Switzerland

Via Doragno 1

6821

Rovio, Switzerland

Architect

deltaZERO SA - De Angelis - Mazza Architects

Via Zorzi 18, 6900 Paradiso, Switzerland (CH)

dz@deltazero.net

Contact Details

Dr Arch. Cristina S. Polo López

SUPSI - University of applied sciences and arts of southern Switzerland

cristina.polo@supsi.ch

+41 58 666 63 14

Other Information

Related publications
Magazine "Tuttocasa"

Single-family house, restoration and new building extension. Private residence building (historic not-listed building in Ticino) with NZEB target using also solar renewables energy in an integrated roof solution. The castle of Doragno was born from the transformation of an ancient medieval castle. The original stone walls are highlighted by the large windows that complete the volume of the existing building. An integrated photovoltaic system and solar collectors are installed on the roof.

GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Energy performance

45,62 kWh/m2.y

Climate Zone Cfb

Altitude 497 m a.s.l.

HDD 146

CDD 0

Protection level Not listed

Conservation Area:
No

Level of Protection:
No LBC protection, Swiss Law on the protection of cultural heritage

Building age before 1600

Year of last renovation:
2017

Year of previous renovation:
1980

Building use Residential (rural)

Secondary use:
NA

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

Number of occupants/users:
6

Building area Net floor area [m²]: 490,0

Building typology:
Detached house

Number of floors:
3

Basement yes/no:
Yes

Number of heated floors:
3

Gross floor area [m²]:
644,0

Thermal envelope area [m²]:
644,0

Volume [m³]:
2279,0

NFA calculation method:
SIA 416

Construction type

Stone masonry wall

External finish:
Exposed stonework

Internal finish:
Exposed stonework

Roof type:
Pitched roof

+ MORE - LESS

East elevation after interventions © L. Carugo

North elevation after interventions © L. Carugo

South elevation after interventions © L. Carugo

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

The castle of Doragno was born from the transformation of an ancient medieval castle into a private residence where the existing building, which did not enhance the castle, has been subsequently restored, giving a new breath to the ancient walls of the building, and completed with a new zero-energy building (NZEB) also using renewable solar energy in an integrated roof solution. The original stone walls are highlighted by large windows that complete the volume of the existing building. An integrated photovoltaic system and solar collectors are installed on the roof.

Urban context

The castle of Doragno had a strategic location: it was build on a promontory and it was a point of observation and defence along the way to the Mara and Intelvi valleys. It was a part of a path bordered by fortified castles and watchtowers built at regular intervals on the way to the Alps.

Heritage Assessment Files

General file

State of repair

Conditions of the envelope

The building was restored preserving the walls and completing the volume with new materials that with the aim not to drown out the old part of the building, but to enhance it. The building is used as a private residence and consists of two main buildings, one to the west that includes a basement and 2 floors above ground and one to the east that includes 3 floors above ground.

Description of pre-intervention building services

Defence castle built during the war between Como and Milan (1118-1127). In the last fifty years the building had mono-familiar residential use.

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION

In building restoration and conservation field, the architects of the project considers that the following aspects need to be preserved: 1: the volume, the shape of the building 2: the skin of the building 3: the history of the building

Heritage Value Assesment

In this project it was chosen to preserve only the medieval part of the building. This choice was made because the interventions done in the sixties do not help to preserve the history of the castle and where even hiding some medieval parts. The cultural heritage office supervisors approved the project and agreed with reflections and considerations from architects. In this project the architects have re-created the shape of the castle using modern materials that differ from the original ones but don't dominate and discretely approach to ancient parts.

Aim of retrofit

Renovation + Extension

Special focus in this project has been the conservation of the ancient walls of the medieval castle, considering modern comfort standards with the aim of achieving a building ad a high standard of energy efficiency, NZEB

Lessons learned

The transformation should respect the past and take into account the fact that the distortion of a territory, without guidelines or without preserving some "key" element, can create disaffection towards the territory itself: we no longer recognize each other, nothing is more part of our experience. It is therefore necessary to evaluate with farsightedness how much and what to preserve of the heritage that the past gives back to us. If this assessment is undoubtedly complex, even how to intervene and how to conserve it are no less so and it will necessarily have to be evaluated case by case. The possibilities are innumerable. The first alternatives we are facing are essentially three: historic buildings can be reused by changing their intended use or they can be reused by maintaining the same destination or they can still be preserved as simulacra of the past to which they belonged. With regard to the actual intervention, in addition to the needs of the client, the principles on which to base the project should be respect for the work, authenticity (not creating a "historical forgery") and consideration of the context in which the building fits.

Stakeholders Involvement

Public sector
Ufficio dei beni culturali
Viale Stefano Franscini 30a
Tel.+41 91 814 13 80

Architect
deltaZERO SA - De Angelis - Mazza Architects
Via Zorzi 18, 6900 Paradiso, Switzerland (CH)
dz@deltazero.net
Tel.dz@deltazero.net

Energy Consultant
Termoconsult srl
via Ugo Foscolo 2, I-21018, SESTO CALENDE (VA)
roberto.fusetti@termoconsult.info
Tel.+39 0331 92 30 26

Structural Engineer
Chiesa&Partners
via Livio 24, CH-6830, CHIASSO
info@chiesaepartners.ch
Tel.info@chiesaepartners.ch

Services Engineer
GreenKey Sagl - Kim Bernasconi
Via Ceresio 45 CH-6963 Pregassona
info@greenkey.ch
Tel.+41 91 630 64 91

Tools used

Was the renovation process done following a specific methodology? SIA 380/1

Energy calculation SIA 380/1
Hygrothermal assessment No
Life Cycle Analysis (LCA) No
Other No

Tutto casa p.1 Tutto casa p.2 Tutto casa p.3

RETROFIT SOLUTIONS

External Walls

Stone masonry wall

The restoration project started from the right premise of completing what remained of the walls of the tower to return the shape so that in the surrounding landscape the building of the past once again became legible.

In this project we have re-created the shape of the castle using modern materials that differ from the original ones but don't dominate and discretely approach to ancient parts.

Wall: detail with internal wall © Delta zero

U-value (pre-intervention) [W/m2K]: 0,9 W/m²K U-value (post-intervention) [W/m2K]: 0,24 W/m²K

More Details

Original wall build-up

Stone - Stone wall:
500 mm

Plaster - Plaster (internal):
30 mm

Retrofitted wall build-up

Stone - Stone wall (extension stone + brick):
500mm

Insulation - Insulation:
100 mm

Other - Vapour barrier:
1 mm

Air gap - Air layer:
30 mm

Plaster - Plasterboard (internal):
25 mm

Windows

Glazed-facade

The existing wood-windows with single glass have been replaced with aluminium-windows with thermal cut and triple glazing

Windows

Detail small window section © Delta zero

Existing window U-value Glass [W/m2K]: 5,0 New window U-value Glass[W/m2K]: 0,6 Existing window U-value Frame [W/m2K]: 3,0 New window U-value Frame [W/m2K]: 1,4

More Details

Existing window type	Different types fo small windows
Existing glazing type	Single
Existing shading type	Outer shutter
Approximate installation year	1980

New window type	Different types of windows: small ones and glazed-facade
New glazing type	Double and triple
New shading type	Roller blinds
New window solar factor g [-]	0,45

Other interventions

ROOF

GROUND FLOOR

ROOF

the coverage of the west wing has remained unchanged, while that of the east wing, which had a single sloping slope towards the north, was carried out with a double pitch

The 20th century works were demolished and the new parts were made of steel and glass, keeping the lines of the new volumes as simple as possible.

U-value (pre-intervention) [W/m2K] 1 U-value (post-intervention) [W/m2K] 0,2

More Details

Original roof build-up

Tiles - Old tiles:
50 mm

Other - Air:
50 mm

Other - Wood:
30 mm

Other - Insulation:
50 mm

Other - Wood:
30 mm

Retrofitted roof build-up

Other - PV glass panel:
8 mm

Other - Insulation Isotec:
100 mm

Other - Insulation Celenit:
75 mm

Other - Wood:
27 mm

GROUND FLOOR

Existing floor were complietely removed and replaced

The 20th century works were demolished and the new parts were made of steel and glass, keeping the lines of the new volumes as simple as possible.

U-value (pre-intervention) [W/m2K] 0,9 U-value (post-intervention) [W/m2K] 0,25

More Details

Original groundfloor build-up

Other - Floor tiles:
20 mm

Concrete slab - Concrete:
150 mm

Other - Stone:
100 mm

Retrofitted groundfloor build-up

Other - Stoneware tiles:
30 mm

Other - Plaster boards:
40 mm

Other - Air layer:
220 mm

Concrete slab - Concrete:
180 mm

Insulation - Double layer :
120 mm

Other - Stone:
100 mm

HVAC

HEATING

VENTILATION

AIR CONDITIONING

DOMESTIC HOT WATER

HEATING

The new heating system consists of a reversible air-water heat pump powered by the photovoltaic system on the roof. The thermal energy produced that is used to heat, cool and produce domestic hot water becoming completely free and renewable. Distribution is made both from radiating floors and fans. The raised floor (Floortech patent, deltaZERO concept), dry laid and demountable, thus giving a high future flexibility, is composed of two functional layers, one load-bearing and the other thermally active: the lower layer, thermo-active, consists of radiant panels of the reversible heating and cooling system.

Being a new system, which integrates into the newly constructed building, it does not compromise the existing castle building, there are no compatibility and conservation problems.

More Details

	New primary heating system	New secondary heating system
New system type	Heat pump	Solar Thermal
Fuel	Electricity	Sun
Distribuition system	Radiating floor	Radiating floor
Nominal power	44.8 kW	- kW

VENTILATION

A mechanical ventilation system with heat recovery (MHVR) was installed which bring fresh air into all habitable areas without letting the heat escape. Stale air contaminated with humidity, toxins and smells is extracted from grilles in toilets and wet rooms. By continuously supplying preheated air into living areas and extracting contaminated air from wet rooms, you create a whole house ventilation system. Fresh air is fed directly from outside into the ventilation system recovering the heat taken from the extracted air that is used to warm the fresh filtered air in the heat exchanger and then enters the ducting system previously preheated.

Being a new system, which integrates into the newly constructed building, it does not compromise the existing castle building, there are no compatibility and conservation problems.

Basement plan with ventilation system © DeltaZero

Ground floor with ventilation system © DeltaZero

More Details

Original roof build-up	New ventilation system
Type ventilation system	Centralized
Type flow regime	Overflow
Heat recovery	Yes
Humitidy recovery	No
Nominal power	250-1200 W kW
Electric power	1,2 kW
Control system	Remote control (RC)

AIR CONDITIONING

Electric reversible air-water heat pump powered by the photovoltaic system on the roof. By reversing the operating cycle, it is possible to cool the rooms during the hot season by using the same operating principle.

Being a new system, which integrates into the newly constructed building, it does not compromise the existing castle building, there are no compatibility and conservation problems.

More Details

	New cooling system
Type	Heat pump
Distribuition system	Fan
Nominal power	40 kW
Electric power	14,6 kW

DOMESTIC HOT WATER

The production of domestic hot water is provided by the solar collectors integrated in the south pitch roof in the new building.

The selection of roofing materials allows the integration of solar systems in order to make a uniform surface, that consider the aesthetic characteristics of the solar thermal panels and their geometry and position in the roof. Solar thermal modules are coplanar to the roof and the similar aspect to solar photovoltaics pannels in order to minimize their visibility from the sorrunding enviroment.

More Details

	New DHW system
Type	with heating system
Hot_water_tank	Yes
With heat recovery	No

RENEWABLE ENERGY SYSTEMS

SolarThermal

Photovoltaic

SolarThermal

Solar thermal collectors has been integrated in the south-east roof pitch for the production of DHW domestic hot water and for heating.

Solar thermal collectors are perfectly integrated in the roof.

More Details

	SolarThermal System
Type	Flat collector
Collector area	5,0 m²
Elevation angle	15,0
Azimuth	145,0
Overall yearly production	3780,0 kWh
Heating_contribuition	0,0 kWh
DHW contribuition	3780,0 kWh
Cooling contribuition	0,0 kWh

Photovoltaic

Photovoltaic system integrated in the south-east and south-west slopes of the roofs.

The photovoltaic system is perfectly integrated in the roof.

More Details

	Photovoltaic System
Type	Monocrystaline
Collector area	100,0 m²
Total nominal power	16,4 kW
Elevation angle	15,0
Azimuth	45,0
Overall yearly production	16400,0 kWh
Heating contribuition	0,0 kW
DHW contribuition	0,0 kW
Cooling contribuition	0,0 kW
Lighting contribuition	0,0 kW