GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Villa Capodivacca

, Italie

Architect

Lucia Corti

Laboratorio di Architettura Ecologica, Padova, Italy

Lucia.corti@architetturaecologica.net

Contact Details

Giovanna Franco

University of Genoa, Italy

giovanna.franco@unige.it

Arch. Lucia Corti, view of the main facade of the Villa after the renovation

The restoration and energy refurbishment of Villa Capodivacca in Saccolongo, in the province of Padua, is among those we can define "low impact". The wise combination of new functions and adequate technical solutions has allowed the historical characteristics and the original atmosphere of the building to emerge that have been handed down over the centuries. From the intersection of the differentiated use of the three floors of the villa, the problems encountered and the constraints imposed by the Superintendence, an articulated project of restoration, static restoration and plant and energy renovation was born, which has been declined in different ways at the various levels (wall insulation by means of dry radiant panels, roof insulation, hybrid boiler and heat pump system and centralized controlled mechanical ventilation).

GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Energy performance

319 kWh/m2.y

Climate Zone Cfa

Altitude 20

HDD 2344

CDD 286

Protection level Listed

Conservation Area:
Oui

Level of Protection:
Decreto di vincolo 6/2/1076 ai sensi della legge 1089/39 - DLgs 42/2004

Building age before 1600

Year of last renovation:
2017

Year of previous renovation:
1970

Building use Residential (urban)

Secondary use:
Residential (rural)

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

Number of occupants/users:
8

Building area Net floor area [m²]: 748,16

Building typology:
Detached house

Number of floors:
3

Basement yes/no:
No

Number of heated floors:
3

Gross floor area [m²]:
930,0

Thermal envelope area [m²]:
1453,95

Volume [m³]:
3502,93

NFA calculation method:
Useful area (it)

Construction type

Brick masonry wall

External finish:
Rendered

Internal finish:
Plastered (on hard)

Roof type:
Pitched roof

+ MORE - LESS

Arch. Lucia Corti, view of the ground floor after the renovation, the main central hall covered by old renaissance vaults

Arch. Lucia Corti, view of the ground floor after the renovation, the living room covered by old renaissance vaults

Arch. Lucia Corti, view of the main floor (first floor) after the renovation, main hall

Arch. Lucia Corti, view of the dining room at the second floor

Arch. Lucia Corti, view of the dining room at the grund floor

Arch. Lucia Corti, view of the kitchen at the first floor

Arch. Lucia Corti, view of one of the bedrooms at the first floor

Environmental context of the surroundings; the Villa belongs to a rural system

Arch. Lucia Corti, plan of the ground floor, on the left the typical scheme of the rooms, divided through the main hall

Arch. Lucia Corti, plan of the first (main) floor

Arch. Lucia Corti, plan of the second floor

Arch. Lucia Corti, the state of conservation of the north facade, characterized by biological attack, mould, surface deposits on plaster

Arch. Lucia Corti, ground floor, view of the main central hall before the renovation

Arch. Lucia Corti, first (main floor), view of the main hall before the renovation

Arch. Lucia Corti, First floor, detail of the timber floor called "sansoviniano" (deriving from Jacopo Sansovino, Italian Reinassance Architect)c

Arch. Lucia Corti, Ground floor, detail of the structural brick vaults corresponding to the first constructive phase

Arch. Lucia Corti, Ground and firs floor; details of the pavement (old ceramic) and of a stone small gutter

Arch. Lucia Corti, First floor, detail of the bedrooms

Arch. Lucia Corti, First floor, details of the main hall

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

The main building of Villa Capodivacca, built in XVI century and later enlarged, is based on three levels. The villa develops around the space of the central passing salon, with a large coved vault. It has undergone, in the following centuries, various interventions of enlargement and transformation; of the XVIII century is the raising of the volume, with the addition, on the main facade, of the triangular tympanum typical of the Venetian villas. The main body of the villa is flanked by a park of ancient trees and is connected to the colonnaded body of a farmhouse, probably built in the early 1800s. The ground floor is the original core of the complex (XVI century). Built initially as a fabric used to stall the goods arriving from the river, the ground floor consists of a large passing hall. On the sides of the hall are the rooms, four corner rooms of almost square shape and two service rooms. The first floor assumes the characteristics of the noble country residence: the subdivision of the rooms faithfully reproduces that of the ground floor but the heights, materials and finishes are adapted to the different use compared to the rooms below. The rooms on the second floor were originally used as servants' quarters. From a rural and holiday residence, used mainly in summer, the Villa has been transformed during XX century in permanent residence of different families. The situation has changed with the sale of the villa, which has been purchased by three different families, which are located on three different levels and each floor has been used for a different purpose.

Urban context

The building belongs to the Venetian villas system. The location of the villa and the architectural typology make this artefact a fascinating testimony to the civilization of the Venetian villas which had in Jacopo Sansovino and Andrea Palladio two of its greatest interpreters. The complex is made up of a group of buildings along the course of the Bacchiglione river, inside a fund that today measures just over three hectares and is located in a bend in the right bank of the river.

Heritage Assessment Files

ListaBeni_Vinvoli in rete.pdf

State of repair

Conditions of the envelope

The Villa was affected by material degradation especially in north façade and indoor discomfort. It also needed structural consolidation in the roofing structure. In the past, to make the attic practicable, the tie-rods and the truss monks had been cut and metal "C" profiles had been laid to contain the thrust of the roof structure. The metal structure had not been properly dimensioned and, at the same time as the tie-rods were cut, some cracks had opened in the walls below. It was necessary, during the intervention, to immediately improve the seismic protection of the structure.

Description of pre-intervention building services

Since the '70s the structure has been adapted to winter use through the installation of gas stoves, one for each room, with poor results from the point of view of comfort and considerable management costs that in recent decades have increased exponentially. During the winter, at full capacity, temperatures were about 17° on the ground floor, 14°-15° on the first floor and 15° in the attic. The insulated roofing under the roof with 3 cm of polystyrene and internally with 6/8 cm thick fibreglass provided, even during the summer, environmental conditions at the limit of tolerance. The average energy consumption, very high, was 340 kWh/sqm per year.

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION

The intervention is classified as important renovation but also restoration, as it concernes a listed building. This means that load masonry walls, horizontal timber structures and brick vaults (over the ground fool), as well as timber roof structure are preserved and consolidated. The same for internal and external plaster and other finishing materials (as roof tiles)

Heritage Value Assesment

The Villa is subject to protection by the Soprintendenza Archeologia Belle Arti e Paesaggio. Every intervention must preserve the morphological, spatial and material characteristics of the complex. Particular attention was even in the conservation of facades (no possibility of external insulation coating).

Aim of retrofit

Renovation

From the intersection of the differentiated use of the three floors of the villa, the problems encountered and the constraints imposed by the Superintendence, an articulated project of conservation, structural restoration and energy renovation was born. The intervention has been declined in different ways at the various levels (wall insulation by means of dry radiant panels, roof insulation, hybrid boiler and heat pump system and centralized controlled mechanical ventilation) preserving the materials and spaces. In addition, the monumental constraint on the building required a dry and completely reversible solution for the installation of the heating elements (wall radiant panels) and insulation. The intervention was approved by the Superintendence in the category of "conservative restoration" (conservation) and therefore the primary objective, in addition to the best management in terms of consumption, was the maximum conservation of architectural, spatial and material values.

Was there any change of use?

From one single family owner to three different family owners (one per floor), different residential occupancy in the year

Was the intervention planned following a step-by-step approach?

Before the intervention the Villa was purchased by three distinct families, located on three different levels and each floor is actually used for a different purpose. The ground floor is used as a guesthouse with a semi-public function, destined to host events and occasional overnight stays. The first floor is used as a holiday residence for about 3 or 4 months of the year. The second floor, attic, has been transformed into a permanent residence for a family of 5 people.

Lessons learned

In the variegated panorama of conservation interventions, that of Villa Capodivacca in Saccolongo, is among those we can define "low impact". The wise combination of new functions and adequate technical solutions has allowed the historical characteristics and the original atmosphere of the building to emerge that have been handed down over the centuries. All the material elements, including the finish, were preserved; in the roof structure the tiles were removed, cleaned and re-assembled; the insulation layers and the new drywall radiant systems were placed over the existing interior finishes. The only elements that have been replaced are the windows, due to their state of preservation, replaced with wooden elements, like the existing ones but with higher performance. However, it should be noted that the existing windows had already been replaced around the 1970s and were therefore not considered by the Superintendence as historical elements to be protected.

Stakeholders Involvement

Private Sector
Giulia Tissi, Federico Fioretta, Benedetta Tissi, Antonia de Besi, Alberta de Besi, Antonio Gallo, Matilde de Besi e Antonio Tissi .
Via Scapacchiò est n. 5, Saccolongo.

Architect
Lucia Corti
Laboratorio di Architettura Ecologica, Padova, Italy
Lucia.corti@architetturaecologica.net

Energy Consultant
In Enrico Pedretti Steping
VIA ARE 9, PESCANTINA (VR)

Structural Engineer
Ing. Stefano Dibiasi
Via Sabbadin 19, 35010, Limena (PD)
info@sheconsulting.it

Tools used

Was the renovation process done following a specific methodology? Italian DECREE 26 June 2015. - Application of the methodologies for calculating energy performance and definition of the prescriptions and minimum requirements for buildings. - Schemes and reference methods for the compilation of the technical project report for the application of the prescriptions and minimum requirements for energy performance in buildings. - Adaptation of the Decree of the Minister of Economic Development, 26 June 2009 - National Guidelines for the Energy Certification of Buildings

Energy calculation Edilclima
Hygrothermal assessment Ediclclima

RETROFIT SOLUTIONS

External Walls

brick masonry wall

The entire top-floor envelope was internally insulated with a coat of mineral insulating panels based on calcium silicate hydrates.

Application of a reversible insulation layer in the internal surface of the walls and new finishing

Arch. Lucia Corti, dry laying of wood fibre insulation on the walls of the main floor, behind the new installations

Arch. Lucia Corti, installation of radiant systems for heating on the first floor walls

Arch. Lucia Corti, installation of radiant panels for summer and winter air conditioning on the second floor

Arch. Lucia Corti, installation of radiant panels for heating on the first floor

U-value (pre-intervention) [W/m2K]: 1,724 W/m²K U-value (post-intervention) [W/m2K]: 0,39 W/m²K

More Details

Original wall build-up

Render - lime mortar:
30 mm

Brick - Brick masonry:
250 mm

Plaster - lime mortar:
30 mm

Retrofitted wall build-up

Render - not altered, restored:
30mm

Brick - Brick masonry:
250 mm

Insulation - Calcium silicate panels:
80 mm

Plaster - New internal plaster:
30 mm

Windows

timber frame and double glazing dating around 1970

The new windows have similar shape and materials to the existing frames (timber). The frames are in lamellar larch wood and the double low emissive glass (3 + 3) has argon gas in the air gap.

The new windows, recurring to traditional materials (wood) have a better performance; their replacement is approved by the protection bodies because existing windows the existing windows had already been replaced around the 1970s and therefore did not constitute elements of historical and architectural character to be protected. The choice was to keep a frame made of traditional, natural material (wood) with better energy performance (it was not a question of preserving seventeenth-century frames). In this case it was not the material degradation that justified the replacement of the elements but rather the low historical value combined with poor environmental performance.

Arch. Lucia Corti, new windows have the same timber frame and better energy performance; they maintain the same architectural appeal

Arch. Lucia Corti, north facade; existing windows have already been substituted in the '70s (timber frame)

Pozzobon serramenti, example of the new thermal certified components

Existing window U-value Glass [W/m2K]: 3,0 New window U-value Glass[W/m2K]: 1,1 Existing window U-value Frame [W/m2K]: 1,9 New window U-value Frame [W/m2K]: 1,7

More Details

Existing window type	Casement window
Existing glazing type	Double
Existing shading type	Outer shutter
Approximate installation year	1970

New window type	Casement window
New glazing type	Double
New shading type	Outer shutter
New window solar factor g [-]	0,51

Other interventions

ROOF

OTHER

ROOF

The roof insulation work was preceded by a careful analysis of the healthiness of the primary and secondary wooden structure, especially with regard to the main beam heads. Although they appeared to be healthy and intact, the internal analysis revealed that the upper part of the beams in contact with the tiles was damaged and suffering. The consolidation of the beam heads took place by inserting steel blades into the deteriorated portion and, in some cases, by adding concrete to the parts of the beams that had been cleaned from the deteriorated portions. Once the structure had been restored, the roof was insulated. Here, the need to combine summer comfort, using a material of sufficient thickness and low thermal conductivity, with the safeguarding of the aesthetic prerogatives of the façade and its elements, led us to withdraw the wood fibre insulation package and replace it, near the cornice, with light, thinner insulation.

The soluton was compatible because of the nature of insulation material (fibre wod) and not alteration of the external shape, even conservation of old tiles

arch. Lucia Corti, graphic thermal verification of the node around the eaves cornice

arch. Lucia Corti, graphic thermal verification of the insulation of walls

Arch. Lucia Corti, installation of the steam barrier layer and the structure supporting the wood-fibre insulation layer

Arch. Lucia Corti, laying of wood fibre insulation, 16 cm thick

Arch. Lucia Corti, constructive phases on the roof (mantle). Dismantling of tiles, replacement of damaged tiles, selection of old tiles to be recovered.

Arh. Lucia Corti, state of preservation of the terracotta eaves cornice

Ach. Lucia Corti, view of the rooms at the third floor and of the pre-existing radiant system

Arch. Lucia Corti, section of the roof structure. Consolidation of the roof structure for verification of compliance with seismic action. In yellow the elements to be removed, in red the steel elements to be inserted

U-value (pre-intervention) [W/m2K] 2,38 U-value (post-intervention) [W/m2K] 0,221

More Details

Original roof build-up

Tiles - ceramic tiles traditional truncated cone shape:
30 mm

Other - plaster:
30 mm

Retrofitted roof build-up

Tiles - the same tiles were conserved, cleaned and posed on the new layers:
30 mm

Other - timber structure:
200 mm

OTHER

The consolidation of the roof, prior to all others, was carried out by means of: - the installation in the attic of new planking screwed and glued to the existing one; - the connection between the new planking and the wall structures using bolted metal plates; - the installation of new metal tie-rods in a raised position with respect to the original; - the application, on the internal side of the vertical walls of the attic, of reinforced structural plaster based on hydraulic lime with suitable connectors.

From the intersection between the differentiated use of the three floors of the villa, the problems encountered and the constraints imposed by the Superintendence, an articulated project of restoration, static restoration and plant and energy requalification was born, which has been developed in different ways on the various levels.

Arch. Lucia Corti, view of the space under the roof, the trusses consolidated with steel elements and the installations

Arch. Lucia Corti, consolidation of the roof structure and timber foor of the third floor with the installation of a new cross-beam planking and steel reinforcement on the timber trusses

HVAC

HEATING

VENTILATION

AIR CONDITIONING

DOMESTIC HOT WATER

HEATING

As each floor of the villa is subject to different uses, comfort requirements and cost expectations were also different. On the ground floor, intended for occasional use, new radiators were simply installed in place of gas stoves, radiant terminals with better performance. These measures have increased efficiency with a considerable improvement in energy production and storage. On the second floor, where a family home was located, it was necessary to obtain a good level of air conditioning both in winter and summer. For this reason an autonomous thermal power station was installed with a hybrid system (boiler and heat pump) that produces both hot and cold water. To guarantee humidity levels compatible with summer air conditioning, a centralised controlled mechanical ventilation system with built-in dehumidifier was installed.

Conservation of all the significative materials and characters

Arch. Lucia Corti, installation of the new reinforcement board on the second floor and of the the installations on the insulating layer counter-wall

More Details

	New primary heating system
New system type	Heat pump
Fuel	Gas
Distribuition system	Radiating wall
Nominal power	102,43 kW

VENTILATION

Finally, to guarantee humidity levels compatible with summer air conditioning, a centralised controlled mechanical ventilation system with built-in dehumidifier was installed.

As already specified

More Details

Original roof build-up	New ventilation system
Type ventilation system	NA (Natural)
Type flow regime	NA (Natural)
Heat recovery	No
Humitidy recovery	No
Nominal power	0,10 kW
Electric power	0,0 kW
Control system	on/off

AIR CONDITIONING

On the second floor, where a family home was located, it was necessary to obtain a good level of air conditioning both in winter and summer. For this reason, an autonomous heating plant was built with a hybrid system (boiler and heat pump) that produces both hot and cold water.

As altredy written

More Details

	New cooling system
Type	Heat pump
Distribuition system	Radiating wall
Nominal power	9,25 kW
Electric power	1,5 kW

DOMESTIC HOT WATER

Linked to the new system

As written for all other interventions

Arch. Lucia Corti, installation of new pipes

More Details

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

Energy Efficiency

Energy Performance

Energy performance certificate: Attestato di Prestazione Energetica
Voluntary certificates: No

Energy Use

Heating
Primary Energy 361,88 kWh/m2.y
Consumption_estimation_Before: 338 kWh/m2.y
Consumption_estimation_After: 319 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: Steady state simulation (e.g. EPC, PHPP)
Consumption_estimation_Including_DHW: Oui
Consumption_estimation_After: 361,88 kWh/m2.y

Internal Climate

Indoor Air Quality

On the first floor, with very significant inter-floor heights (up to 4.50 metres), winter air conditioning with low temperature terminals (radiant wall panels) to lower consumption at the same time achieve greater indoor comfort thanks to the radiant effect of the panels, which work by radiating their heat right at the right at the human body.

Costs

Financial Aspects

Private financing

Running Costs

Lifecycle cost
No