Open House

[Originally published in Bauwelt March 2022]

Since the emergence of the pandemic, outdoor private space has come to be newly appreciated as a vital component of urban dwellings. Be it a balcony, a terrace, a loggia, a patio or a courtyard, private outdoor space not only improves quality of life on its own, but also vastly improves the livability of adjacent indoor spaces when there is transparency between the two. This is even more the case when the two realms can be physically joined –weather permitting– through operable openings that are generous. Such a fusion of interior and exterior space has long been an ideal of architectural modernism, specifically the hygienist movement of the 1930s, but in the context of today’s climate emergency this ideal comes with an increasingly elevated environmental cost that demands new architectural approaches.

Casa Costa, a Barcelona courtyard house designed by local firm Arquitectura-G, demonstrates how the modernist ideal of indoor-outdoor transformable space can be achieved in today’s energy context through careful attention to architectural detail and the use of high-quality, energy-efficient doors and windows.   

Casa Costa is situated in a low-rise but compact neighborhood that climbs one of Barcelona’s seven hills, occupying a deep lot bounded by party walls on three of its four sides. Of course, such a lot demands some sort of rear or intermediate void in the building volume to permit light to enter from more sides than merely the façade. Economic imperatives dictate that such outdoor voids must be minimized in order to maximize interior floor area, which results in “patios” that are essentially residual, and that leave a great deal to be desired. With Casa Costa, however, the courtyard is the very generator of the architecture; the heart and soul of the house.  

The house itself is an elongated, two-story high L-shaped volume in plan, the shorter wing of which faces the street such that the courtyard occupies a generous quadrant at the rear of the lot. The southwest orientation of this quadrant provides optimum solar exposure for both house and courtyard vegetation comprising trees. Both courtyard facades are clad entirely with glass sliding doors on both levels, in sharp contrast with a street façade that is minimally fenestrated. The house thus turns its back to the street while wholeheartedly embracing its courtyard garden.  

Every detail of Casa Costa’s architecture has been designed to maximize both visual as well as physical exposure to its courtyard garden. The longer courtyard façade is divided into four sliding door modules per floor that stack when fully opened, creating an opening of 7.3 m, while the two modules of the shorter façade open 1.6m. However, the corner where both lengths of sliding doors meet is frameless, which makes it possible to open 8.9 linear meters of the courtyard facade. Moreover, the space is thereby opened volumetrically, in three-dimensions rather than the two dimensions of a simple planar opening. The perceptual effect is rather stunning, as the boundary between interior and exterior becomes much more ambiguous when a corner is opened. Details such the absence of a structural column at the very point where it is needed the most, as well as sliding door guide-rails that are embedded in floors and ceilings help to augment this perceptual ambiguity. When the house is fully opened, it becomes, to all effects, a covered outdoor space; not unlike the cloister of a Medieval monastery or the veranda of a Renaissance courtyard.

With its minimal openings, the front façade is for all intents and purposes a fourth party wall. An opaque entrance door with a small transom window provides the only opening at ground level, where all rooms are orientated entirely toward the courtyard. On the upper floor, the front façade is punctured by two window openings whose flush-mounted opaque white lacquered steel exterior shutters become camouflaged with the lime mortar façade when shut. Not unlike the Alhambra of Al Andalus, the exterior reveals almost nothing of the interior.

The courtyard of Casa Costa is a sort of open terrarium with no paved surfaces whatsoever, as it is not intended to be occupied (except for garden maintenance). Its only purpose is to provide the house “interior” with natural light, air and views of vegetation. The courtyard’s tall deciduous trees form part of this house’s climate control system, letting sunlight penetrate the house in winter but shading it in summer.   

Casa Costa could have been built larger, with more rooms, if a smaller patio resembling a lightwell had been opted for. But the flexible relationship between the interior and exterior spaces, to say nothing of the beauty of the courtyard, would be absent. Casa Costa ultimately demonstrates that in today’s climate, we need to build less and at the same time build much better.