Variation of modes of use: functions, users, schedules, etc.

Relationship between the ownership and the form of the investment that allows the transformation

Variation of the overall dimensions of the building

Proportional relationship between new spaces and existing spaces

Relationship between the structural adjustments and the existing structure

Relationship between the forms and types of pre-existing materials and those of the new intervention

Relationship between the image of the new and the image of the existing (mimesis / contrast)


Formello, Rome


Malfona Petrini Architecture (Lina Malfona, Fabio Petrini, Simone Petrini, engineering: Tommaso Malfona)



Lina Malfona – Casa al praticello (Slot House)

PROJECT - Main Infos

PROJECT: Lina Malfona – Casa al praticello (Slot House)

LOCATION: Formello, Rome

YEAR: 2017

ARCHITECT / FIRM: Malfona Petrini Architecture (Lina Malfona, Fabio Petrini, Simone Petrini, engineering: Tommaso Malfona)

BUYER: Private

SURFACE: 80 sqm

PRICE: € 100.000

Slot House is located in the countryside north of Rome, Formello, where since 2009 the architectural firm Malfona Petrini work on private dwelling, focusing on new constructions. This time the point of departure was a a farmstead that was in need of repair and recovery. The idea was to preserve the farmstead as it was, and build a framework around it: a covering structure that would function as a portico and protect the house. Over time, beneath this framework, additional residential modules could be erected to expand the house, according to the theoretical model of the 'Slot House'. The 'Slot House' model offers an interesting possibility to use the enveloping framework for completing, extending or re-cycling existing buildings, like the high number of farmhouses (casali) which dot the Roman countryside. For this reason, it is deemed suitable to transform this architectural device in a building rule, in order to recover ancient buildings that are often ruined or abandoned. Entire villages of low-cost houses can be erected, starting from this basic covering structure.

WHAT - Program

BALANCE BETWEEN CONSERVATION AND REPLACEMENT: The new program is in balance with the existing one.

Building regulations required that this house retain the original dimensions of the farmhouse. Thus, it could not be extended except through the construction of local “accessories” for the house, such as a toolshed, a pool, a locker room, a greenhouse, and an open-air kitchen. At this point, we decided to plan the house’s expansion through these accessory spaces. These were conceived, then, as utilizable in a temporary, shape-shifting manner; in other words, they were conceived as typologically flexible modules. At the moment, this house has already been expanded twice, and in the future the entire residential core could be moved up, over the roof (as it occurs in the expansion of Australian houses). This way, the ground floor will be available to receive any further slots.

WHO - Financing

BALANCE BETWEEN CONSERVATION AND REPLACEMENT: Balanced financing between the original owner and another investor.

Private clients financed the construction of their own house.

HOW MUCH - Absolute Dimensions


BALANCE BETWEEN CONSERVATION AND REPLACEMENT: The overall dimensions are about twice the pre-existing surface.


PREVALENT CONSERVATION / CONTINUITY: The overall dimensions increase moderately with respect to the pre-existing volume.

This house is a reiterable low-cost structure with many possibilities of extension.

HOW MUCH - Relative Dimensions

BALANCE BETWEEN CONSERVATION AND REPLACEMENT: The new spaces are in balance with respect to the pre- existing spaces.

Like the low-cost Electric House (Casa Elettrica) proposed by the Team 7 (Gruppo 7) in 1930, whose price was 60,000 lire, the Slot House price is calculated to be 100,000 euros for an all-inclusive 80 square meters. For further 30,000 euros, it can even be enlarged, covering 120 square meters.

HOW - Design Strategy STRUCTURE

PREVALENT CONSERVATION / CONTINUITY: The supporting structure is mainly the original one.

The Slot House was primarily intended as a place from which to observe the surrounding landscape. The structure of the residential pavilion is made up of a canopy, held up by pillars and conceived as a terrace. It has one defining character: its length. Later, beneath this terrace, the residential cell will be spatially organized in a way recalling the Greek temple in a kind of postmodern version, with its assembly kit of parts: the crepidoma, the cella, the peristasis of columns. Also, the slot house can be made up of a number of different cells that, like slots of a motherboard, can occupy the spaces underneath the above-cited covering. This covering/terrace is intended to be both a technological device and a way of accessing the house from the sky. Thus, it can be furnished with current collectors, and it is perforated to allow aerial transportation devices (for transporting products and people) to enter the residence. In the future, this terrace can work autonomously, as a landing pad or as a refueling station for the flying house.

HOW - Design Strategy MATERIAL

TOTAL CONSERVATION / CONTINUITY: The materials chosen for the new intervention are similar to the pre-existing ones.

Concrete structure covered by plaster; original tile roofing

HOW - Design Strategy IMAGE

TOTAL CONSERVATION / CONTINUITY: The new intervention is in total mimetic continuity with the existing structures.

This house can be considered as a peripheral architecture which reaffirms the value of the countryside within a technological and digital society. This design implements a symbiotic relationship between architecture, engineering and digital technologies, in order to create a low-cost, energy-saving, and self-sufficient residency, almost disconnected from any kind of public network. This building introduces the concept of the 'ultra-residential': it has been designed to be a suburban villa which combines private and public realm, at a time when not just collective life but also business is taking place at home, once again (Lina Malfona, "Ultra-residential. Architectural Explorations in the Roman Countryside", 2018-19). Over time, a substantial part of this house has been turned into a kindergarten.