Architects Stefano Piraccini and Margherita Potente
Piraccini+Potente Architettura
“Fiorita Passive House” is the first multi apartment building (8 units) in Italy with an Xlam wood structure, certified to the Passive hause Institut of Damstraat.
The project involves the construction of a residential building with Passive House standard, through a renovation with demolition and reconstruction with the same volume.
The original building, whose construction is dated 1955, consists of a brick building envelope without any thermal insulation, in accordance with the constructive culture of that period that required only the appliances to meet the energy requirements, without taking into consideration environmental sustainability, energy saving and control of resources.
In this context, a fine-tuned cooperation between client and designer is required, in order to identify a process methodology capable of defining and satisfying the following requirements:
- increase of the number of housing units to optimize the rental income;
- thinner external vertical closure to gain more internal surface;
- minimization of the time required for the construction, in order to reduce the credit interest rate and start generating income earlier;
- minimization of the energy costs in order to reduce the operating costs;
- elaboration of an architectural project capable of manifesting the innovative nature of the business idea, through contemporary formal references and innovative technologies that save energy and guarantee environmental sustainability;
- obtainment of an internationally recognized energy efficiency certification, based on a restrictive and virtuous protocol, in order to achieve the passive building standard;
- contextualize the intervention in terms of renovation to get tax benefits.
To meet the performance requirements, the building will be built using a dry construction system using wooden structural panels (Xlam).
This technology guarantees thinner perimeter walls, high energy performance and a reduction in construction time of approximately 60% compared to traditional wet building technologies.
In this context the choice of the construction system is an Hobson’s choice, since it is a complement to the project objectives: in particular if considering the regulatory requirement of keeping pre-existing shape and distance from borders, a condition in which any increase in thickness of the perimeter walls produces a decrease of the usable area.
Even the reduction of the building time results in a significant advantage in terms of reducing interest rate exposure, guaranteeing a quick income generation through rents when the work is finished.
Given the lower density than traditional buildings, particular attention must be given to summer overheating, employing dimming systems and materials with adequate density capable of slowing down the entry of heat.
The envelope stratigraphy has 40cm thick walls: it is capable of developing high energy performance both in terms of transmittance (U=0.136 W/m2k), and thermal lag (λ=16 hours). To obtain the same performance with a construction in masonry, thicknesses about 30% higher would be needed.
The openings will be realized with triple-glazed window frames (UG=0.6W/m2k), while the insulation and air tightness layers will be continuous on all of the lugs and at intrados, thresholds and quays.
The morphology of the new project, even if tied to the volume and partly to the shape of the pre-existing building, was ennobled by the introduction of architectural elements capable of returning the highly innovative character of the intervention.
The outer surface is characterized by overhangs and sliding shading screens, allowing to modulate the energy supplied through passive radiation.
The wall covering in wood and laminam is ventilated: this technology allows for a convective motion inside the wall, which produces a natural cooling of the interior casing and, at the same time, limits moisture and condensation.
The project anticipates the requirements of the European Directive 2010/31/EU, already implemented by the Italian government, that requires, starting from 2020, the construction of near zero energy buildings.
Download the “Fiorita Passive House” brochure (in Italian)