Penthouse Extension – Flexo Arquitectura

architects_FLEXO ARQUITECTURA: Aixa del Rey + Tomeu Ramis + Barbara Vich
location_Barcelona, Spain
construction year_March 2014
construction costs_796,24 €/sqm
total area_28 sqm
cooperating persons_Riba-Masanell (carpenter)
photography_© José Hevia

The project consists of the extension of a small apartment located on the rooftop of a building from the XIX century in Barcelona. The configuration of this new space has to be undefined, understanding it should be able to hold any use desired until the complete reformation of the apartment. In this way, a volume is designed with a supply of installations that will assure this freedom of use. This new piece of architecture is placed in between the existing volume and the neighbouring wall on the limit of the roof, so to use both existing walls as weight bearing elements; a typical strategy for this type of projects. The premises on which the project is based are very clear: minimum weight, minimum execution time and maximum flexibility.

Therefore, the pavilion is defined through a very simple geometry and built in wood in order to reduce the weight of the extension. In order to accelerate and have better control of the execution timing, the facades were built in a workshop and then lifted with a crane in order to ensemble them together in-situ. On the other hand, the new floors were completely built on the sight. The whole execution timing was of a week; the first 48 hours used for the assembling of the pavilion, while the rest of the time was used for working on installations and finishing touches.

The façades consist of a lightweight framework, formed through wood linear elements, 80x80mm, and OSB panels on both sides and rock wool on the interior of the panel. On the outside a ventilated cladding system was used, defined through a three-layered vertical fir-wood panel, 27 mm thick and 200mm wide, fixed through stainless steel screws on a vertical fir-wood substructure.

The inferior floor structure is built out of 9 laminated beams, 24×12, and held through stainless steel elements fixed on the existing walls. Moreover, the pavilion is placed as a floating element on top of the existing rooftop, built through a typical Coberta a la Catalana, the traditional rooftop from the location, with a pronounced inclination. This floating condition allows water evacuation to flow under the new piece of architecture as if it wasn’t there.

On the other hand, the superior floor is of the same nature as the inferior, only that this one is held through the framework of the facades.