Light: 75 kg/m2 < p ≤ 125 kg/m2

This use of the double skin facade where the outer glass is patterned with a white serigraphy that gradually dilutes as one gets closer to the areas of vision may disappear as rapidly as it has spread. It is an easy way to blur the openings limits. In the case of this hotel in London, the opening is perfectly well defined on the wall in the interior skin. This technique harks back to the effect of traditional interior thin white curtains, except for the important difference that the curtain can be used to cover the openings with a very efficient light diffuser.

The extension of the University of Barcelona’s Faculty of Law was a risky intervention: the erection of 16,000 m2 next to a jewel of rationalist architecture of a smaller size, at about 12,000 m2, being the plot of the new construction considerably smaller than that of the historic building. 

We do not want to evaluate the architectural intervention, but simply mention that resorting to neutrality is perfectly understandable. 

This emblematic building in the London financial district maintains its formal unity beyond the differences in the design of the façades depending on their orientation. The case "Devoid of the human scale (034)" describes the southwest façade of the same building. The southeast and northwest façades attract our attention due to the sobriety conferred by the enormous glazed surface, which is only interrupted every three floors by horizontal bands of stainless steel.

The Forum Building façade has hardly been discussed, perhaps because it was eclipsed by other buildings in the same area and by other aspects of the Forum Building itself. However, after fourteen years, this risky lightweight solution has been successfully integrated into the city’s landscape. The original electric blue has slightly dulled, at the same time as a salty dust patina has added enriching nuances.

On this occasion, Batlle and Roig resort to a curtain wall in which partial structures are assembled at each slab front without physical continuity between them. Glass panes are then supported over the partial structures to close the façade (have a look at the "Cadireta" curtain wall structure). Each two glass panes are framed with an aluminium frame made of unitized panels profiles. So, is this a unitized façade or a curtain wall one? Maybe it is a mixture of the two?

In the ventilated façade of the Institut Geològic de Catalunya (IGC), the inner layer responds to the window distribution that the use of the building requires and the outer layer responds to formal aspects. The perforated corten sheet that clads the entire façade provides an abstract image, behind which domesticity is solved. The perforated metal sheet shows a drawing and plays with transparencies: it is a rich composition resource that is possible in multilayer façades.

Years after the construction of the AC hotel in the Forum area, the one in Sants was built. The construction solution adopted for the rainscreen façade is practically the same in both cases. Again, a lightweight enclosure is employed when the use demands low thermal mass solutions. Again, a reinforced frame supporting the window is the structure required to release an opening in this unidirectional façade structure.

In this case study, we want to emphasize the construction solution applied on the façades and the roof: an ETICS system coated with ceramic tiles. 

The RBA headquarters are not included here to talk about the project as a whole; an analysis that would allow us to highlight very positive aspects. Instead, our focus is the façade and its lack of sincerity.

The two longitudinal façades of the lower volume are articulated from a grid that reproduces the rhythm of the concrete structure. It is not the true “structure” that we see. The façade enclosure covers pillars and slab edges from the outside, hiding them from sight.

Mecanotubo is one of the façade industries that invested heavily in the late 1990s in Catalonia to provide a unitary response to the rainscreen façade.

They opted to adapt stick curtain wall technology to this two-layer façade. As in the Carburos Metalicos façade, the resulting inner sheet provides enough water tightness to consider a drainage cavity, and consequently an outer layer, unnecessary. Here the outer layer acts only as a covering.