Implementation of energy rehabilitation of the building envelope in the “Óscar” residential building on Avda. Castilla y León, 15 – 27. San Sebastián de los Reyes, Madrid
Author: Carlos F. Ruiz - Architect
Actuacion Pareer Cr...

Actuacion Pareer Crece Edifcio Oscar

Project Data

Location:   Avda Castilla y León 15 - 27

Town:    San Sebastián de los Reyes 
Province:    Madrid
Ownership:   “Oscar” Building, residents’ association. 

Architect:    D. Carlos F. Ruiz González - Argía Arquitectura y Gestión


In February 2012, the community of owners of the “Oscar” residential building in San Sebastian de los Reyes invited us, along with 16 other teams, to a restricted contest for projects to provide a technical solution to the problems caused by the constructive and structural defects which the building has had since it was built in 1991.

The building is made up of seven blocks with apartments on the ground, first, second and third floors. Garage and storerooms in the basement. The building is of open block design, with an internal patio in each block, forming a slightly curved tablet of 165 x 27 metres, with long facades oriented to the southeast and northwest.  The total number of apartments is 80. 

Initially, it was about solving the problems generated by deferred deflection in the structure of the building due to the excessive length of beams and girders. This meant a series of corrective actions to the structure, stabilization and repair of the facades and of the vertical and horizontal finishings of the interior of the apartments.

The starting point for the project was a previous expert report which proposed the addition of mullions as a solution to repair the structure in order to shorten the excessive lengths of existing beams and girders.

Our proposal, in which the engineering firm Florentino Regalado & Associates (CYPE) collaborated, won by proposing a stabilization solution for the structure that replaced the mullions proposed in the initial report by a mixed solution of beams, pillars and metal braces working with traction that avoided the appearance of pillars in the garage and considerably reduced both the impact on the interior of the apartments and the costs of execution.

It was this saving in the costs of repair of the structure that allowed us to propose to the owners a repair solution for the facade, which also includes an improvement in the energy efficiency of the building envelope.

Fortunately, we found that the owners were receptive and sensitive to energy efficiency issues, and we launched a study of the improvement measures that could be implemented, taking into account criteria of economic viability and implementation issues.

The baseline requirements meant that the works should be carried out with minimum interference to the habitability of the apartments, which should remain inhabited during the work, except in very specific situations in particular apartments.

Baseline requirements

The building’s exterior facades and those of the inner courtyards were constructed of an external layer of face bricks, plastered on the external side, with a 5 cm chamber housing 40 mm of EPS insulation, and a partition wall of hollow bricks with plaster trim and plaster.

The first step was to undertake an analysis of the energy demand, establishing three classifications depending on the different orientations.

Resultado final fachada exterior edificio "Óscar" Resultado final fachada patio interior edificio "Óscar" Resultado final fachada exterior principal edificio "Óscar"

Initial situation


The study of the energy efficiency of a typical block of the building in its original state, made using Calener-Lider, gave us results for total primary energy consumption of 130.7 Kw/hm2 and CO2 emissions of 28.7 Kg CO2/m2, giving an energy rating of E.

The decision process for improvement measures

In collaboration with INGENIA, the engineering company with which we symbiotically share a work space, we studied the opportunities for energy improvement in each of the elements of the building.
We prepared a list of priorities for a subsequent scaling of the actions based on the finances available to address them.

Trabajos rehabilitación fachada exterior edificio Óscar Trabajos rehabilitación edificio Óscar Trabajos rehabilitación fachada patio interior edificio Óscar

           Rehabilitation works

Thus, the decision was taken to work on the exterior facades, the courtyard facades, the terraces, the roof and the windows. 
Working on the existing individual gas boilers was a process with little chance of success since the situation was very different in each home, with some old boilers, others which had been renovated but were of low efficiency and some cases of high efficiency condensing boilers.

The external facades have been finished with a TAU ceramic translucent solution of large-format porcelain pieces (900 x 450 mm), on an extruded aluminium profile supporting structure fixed with primary anchors to the front of the concrete slab and with secondary anchors to the facade sheet, with support clamps for the stainless steel parts, with PUR insulation of 80 mm and density 35 Kg/m3, projecting it onto the face brick.

Special care has been taken in the solution for the window surrounds and closing mechanisms to minimize thermal bridges and air infiltrations.

For the facades of the interior patios, we’ve chosen a SATE solution from Baumit, with EPS insulation with chemical and mechanical fixing and a “Nanoport” self-cleaning textured finish.

The windows of all the apartments have also been replaced by lacquered RPT aluminium carpentry with triple glass glazing with double chamber type Planilux 6/16mm/Securit 4T/16mm/Stadip 4+4 Guardian Sun, with a U = 1.8 W/m2K. Blinds were installed, which were reinforced for increased isolation and airtightness, with a U = 1.0 W/m2K.

In addition, the under-roof insulation was reinforced with a 10 cm fibreglass blanket between the partition walls and, where necessary, the insulation of terraces and patios was renewed using 40 mm XPS plates.

Finally, improvements have also been made to the lighting installations of the common areas and garage, providing LED lights and sectorized presence detectors.

Final result

After implementing the improvements to the building envelope, the results of the energy efficiency calculations for the typical block are 73.6 Kw/h m2 of total primary energy consumed and 16.2 Kg CO2/m2 of CO2 emissions, giving an energy rating C.

The savings made equate to 44% of the initial parameters and in the case of heating demand, the saving is 53% and reaches 56% in the case of homes with less favourable orientation.


Resultado final fachada exterior edificio "Óscar" Resultado final fachada patio interior edificio "Óscar" Resultado final fachada exterior principal edificio "Óscar"

Final result

By means of interviews with the residents, we’ve been able to verify that, compared to the previous winter, gas consumption this winter has been effectively reduced by magnitudes similar to those calculated (in some cases more). Although this does not constitute a rigorous study, it does reinforce the conviction of the owners that they have made a good investment in the future, besides making an important contribution to sustainability and reducing polluting emissions.


Technical and financial data. Performance of the subsidy programme PAREER-CRECE in the “Oscar” Building in San Sebastián de los Reyes, Madrid.

The building has been energy certified before and after the rehabilitation, using the CALENER-LIDER tool, giving the following results:

The rehabilitation of the building envelope has allowed the building to move from energy class E to energy class C, in CO2 emissions.

Final energy savings of 44% have been achieved.

Reductions in building heating demand of 53%, and up to 56% in the case of apartments with less favourable orientation.

Investment made or “eligible cost”:

€ 1,059,692

Subsidy from the PAREER-CRECE programme

€ 240,000 (22.6%)

Completion of the work:


(IDAE data)

Associated information

Información relacionada

035 – Mejora de la envolvente térmica en un edificio de viviendas existente. Actuación del Programa de ayudas PAREER-CRECE en el Edificio "Óscar"

Vista panorámica del edificio de viviendas