104 Social Housing Units in Borinbizkarra

Memory of project

The Municipal Urban Planning organisation of the City Hall of Vitoria-Gasteiz, Ensanche 21-Zabalgunea awarded by public tender, the development of 104 social housing units in sector 1, Borinbizkarra of Zabalgana. The tender was awarded to ARALAN who presented an architectural proposal prepared by ACXT. The criterion adopted in the tender evaluation considered the urban, architectural, functional and aesthetic value of the proposal.

Situated on a rectangular plot, the building was conditioned by the partial development plan that defined three longitudinal volumes, running north to south, with 6 stories and a tower of 9 stories at the southern end that meets the street. The blocks are connected on the ground floor by large commercial premises facing the street. All the housing units have been proposed to have a floor area of 90 m² and include 3 bedrooms.

The standard housing building consists of 3 bodies which house the stairwell and lift shafts which give access to two apartments on each landing, thus allowing double east-west orientation in each home.

The layout of the apartments seeks to maximize the double North-south orientation of the units with the design of the living room-kitchen area, which constitutes a single longitudinal space from end to end, around which the other areas are situated. This space is limited with two large alcoves at each end, finished off by a terraced at the living room end. This layout reduces the spaces of circulation, thereby allowing the living spaces to be maximized without exceeding the statutory maximum area of 90 m².

Aspects of innovation that are incorporated in the works.

The project seeks to be an answer to the desire of the City Hall of Vitoria to promote the energy efficiency of the housing stock, while working with a very tight budget, as is normal on social housing developments. The decision regarding the orientation of the apartment buildings, the location of the living areas of the same, the size of the spaces and location of the terraces in specific places took place from the very beginning of the project. The construction aspects were also conditioned by the limitations of the budget. Any aspect that varies from traditional building methods must be adequately justified in terms of its contribution to energy requirements; assessing both the elevated economic cost and depreciation in the energy bill.

The treatment of the shell of the building is one of the most effective aspects in relation to construction-energy savings costs. A continuous sheathing or envelope with a slightly higher level of insulation that usual can mean savings on the energy bill of up to 15%. If we add this to the installation of a DHW system and a high-efficiency heating system using condensing boilers and low temperature, supplementing the output of the DHW with solar panels, the total savings can be as high as 44%.

The chosen façade is of steel sheets and insulation material to a thickness of 80 mm, and pine wooden windows which respond to the requirements set out of: low cost, allowing continuous insulation using great thickness cutting out thermal bridges and voids, and constructed using highly recyclable materials.

Text.- Iñaki Garai, Inés López Taberna.