Journal

“The summoning up of architecture in just a few details, so that they become the regulative features of the landscape without interfering with it. Two parallel, tufa walls contain the house (…).The rooting of the structure in the ground by opting for horizontality, digging out a subterranean courtyard bordered by a curved wall and an underground entrance ramp. A partially “submerged” construction is further camouflaged by the radical nature of the simple geometrical design. The use of traditional local materials.
The tufa from Civita Castellana left bare: porous, irregular, rough stone chosen for its expressive qualities, for its clear material appearance, and in order to attenuate the rigour of the rectilinear walls with the calculated imprecision of the details”.¹
Elio Di Franco own, simple words describe the project for the construction of Casa Santilli, a villa situated in the countryside outside of the central Italian town of Viterbo. The architecture is substantial, sober, highly communicative and perfectly intelligible: the distribution of its functions and its residential spaces, arranged in a sequence between the two parallel walls, is clear. The structure is composed of the walls and the wooden roof-frame; the materials, used in a genuine manner, include the pozzolan tufa of the walls, chestnut wood beams and rafters, terracotta roof tiles and travertine flooring.
As well as encompassing the domestic interiors, the walls extend out to create an outdoor eating area and a private garden backing onto the bedrooms; this pergola-style area is characterised by an “aerial arrangement ” of wooden truss beams and roof rafters (uncovered) that project their changing shadow onto the end of the building. The appearance of the building is delineated by these few salient features: the only additions to the rural landscape and the rolling hills and warm colours of the soil, are the isodomic walls covered by a long, pitched roof. It is the presence of the terracotta roof tiles and, even more so, of the reddish local tufa, that help the building blend in so well with the natural colours of this corner of Etruscan Tuscany.
The tufa ashlars forming the regular wall are all of the same format – that of traditional full bricks, only of a larger size – and they create a pattern of courses that emphasise the horizontal development of the load-bearing walls that are clearly the most important feature of the design. The ashlars are solidly bonded together with the help of a grey cement mortar.
The stratified character of the walls is further emphasised by the deep, inset pointing of the parallel horizontal joints which creates a pattern of shadowy lines, interrupted every four courses of ashlars, by thin listels of plaster (containing terracotta dust).
These delicate walled surfaces also feature an elegant composition of small loop-holes and large windows by means of which the house opens out to the world outside.

Davide Turrini

Note
* The re-edited essay has been taken out from the volume by Alfonso Acocella, Stone architecture. Ancient and modern constructive skills, Milano, Skira-Lucense, 2006, pp. 624.
http://architetturapietra2.sviluppo.lunet.it/libroeng
¹ Elio Di Franco, Project Details (unpublished manuscript), n.d., p.1.