Heritage preservation strategies through textiles

1. UNIVERSIDAD POLITÉCNICA DE MADRID SCHOOL OF ARCHITECTURE DEPARTMENT OF CONSTRUCTION AND TECHNOLOGY IN ARCHITECTURE Heritage preservation strategies through textiles Javier Tejera (BATSPAIN) & Juan Monjo-Carrió (UPM)

2. CONTENT • Objective • The cases presented • Patio in a cold and humid climate • Patio in a warm and dry climate • Conclusions

3. OBJECTIVES Textile membranes as an optimal tool for rehabilitation of heritage buildings • Two different strategies are presented: • ETFE cushions double layer for atlatic climate (rainy and cold) • Single layer tensed cone for mediterranean climate (warm and dry)

4. THE CASES PRESENTED (1) • Two different cases are presented: • A small fortress-palace built in the 13th century in Beasain, Guipúzcoa, North of Spain, and • An old cottage in Riba Roja del Turia, close to Valencia

5. THE CASES PRESENTED (2) • The Palacio de Igartza is a small fortress-palace built in the 13th century in Beasain, Guipúzcoa, North of Spain to defend the close bridge access, which is part of the medieval surrounding . • The target now was to cover the central courtyard with minimal intervention due to the high level of cultural protection. • The original restoration project included a heavy steel structure to support a glass skylight, which would introduce important loads to the wooden structure that could be damaged. On the other hand, the heavy visual aspect would reduce the original lightness of the central space. • On the contrary, ETFE offered great lighting and minimum permanent load affecting the wooden structure.

6. THE CASES PRESENTED (3) • The roof was designed as a 40 m2 double layered pneumatic cushion, (250 micron thickness)being the new structure limited just to the borders • According to local regulations, a 0,3 KN/m2 snow load was considered • Wind load was difficult to estimate due to the roof shape (not similar to the standard ones shown in regulations) and to the cushion position, protected by the old roof • A CFD analysis was made to obtain accurate wind loads and ended with an internal pressure of 300/500 Pa without/with external loads

7. THE CASES PRESENTED (4) • A rectangular stainless steel ring made of square shaped tubes was anchored to the wood structure by means of secondary steel separators, and a complex system of extruded aluminium and EPDM clamping profiles was anchored to it to secure the proper cushion installation and sealing • Joints between clamping and structure profiles were hidden with no need of any secondary structure, so from the courtyard nothing would be visible but the profiles and the clamping.

8. THE CASES PRESENTED (5) • ETFE offered also a high level of protection: It allowed a watertight enclosure against the rain, since the Atlantic cost at the North of Spain, is an area of high rainfall • On the other hand, a double layered pneumatic roof provides a better acoustic performance of the courtyard, allowing its use for all kind of events • The greenhouse effect that usually occurs in ETFE enclosed spaces, was an advantage in the case of this climate with 50% of rainy days and an average temperature of 18.2 º C during the summer • Natural light gain was a great advantage as well in this roof

9. THE CASES PRESENTED (6) • The Masía Villa Celiana is an old cottage in Riba Roja del Turia, close to Valencia and to the Mediterranean coast with no special cultural protection • It has been renovated to be used as a celebrations hall, so the functional incorporation of the courtyard by covering it was an important premise

10. THE CASES PRESENTED (7) • The aim of the project was to cover the central courtyard, but due to the climatic conditions in the Mediterranean coast (more than 300 sunny days per year and a summer average temperature of 25.5ºC) the main target was to protect it against heating during the summer, allowing natural ventilation between the textile roof and the building • As a consequence the material should ensure an efficient protection from the sun. A Ferrari 1002 was used

11. THE CASES PRESENTED (8) • The cultural protection level was not significant, so it was feasible to plan a PES/PVC tensile roof anchoraged to the building in eight structural points, that was necessary to reinforce and oversize • The roof geometry was planned as a double cone 550 m2 size, overlapping with the old cottage roof, supported by a “V” shaped mast in one side of the courtyard, with eight perimeter anchoring points. • The bi-conical shape was radial patterned following the main stress directions and optimizing the roll width.

12. THE CASES PRESENTED (9) • The membrane corners were anchoraged by installing four “external” masts in the courtyard perimeter, fixing them to foundations on the ground floor and to the building slabs, and four “internal” masts through the building roof and slabs, down to the ground floor • The perimeter masts were designed in two different heights, allowing an anticlastic geometry, for the sake of stability and water drainage

13. THE CASES PRESENTED (10) • In order to avoid lower corners to lead the water inside the courtyard and the new roof to accumulate more rain that the old one, a new water drainage system was incorporated to channel the rainwater

14. THE CASES PRESENTED (& 11) • The climatic behaviour was secured by the overlapping of the roof, which allows a proper ventilation, and improved by means of two open central high points, which allow the hot air flow out easily • Cp values for the statical analysis were obtained from Tensinet´s European Design Guide for Tensile Surface Structures and verified by means of a CFD analysis. In this way, loads were significantly reduced compared with the ones resulting from the standard regulations.

15. CONCLUSIONS • The incorporation of the courtyards of old buildings to their new functional use, even with cultural protection, can be solved through textile solutions, which can enable their rehabilitation without disturbing visual impacts • With textile techniques and the use of different strategies and materials, similar problems can be solved in different climatic conditions: • The courtyard of an old fortress-palace located in the Spanish Atlantic coast, with a cold and rainy climate, is incorporated to its new use with a watertight, double layer ETFE roof, which enables good natural lighting and sound conditions without visual impact • In a Mediterranean climatic situation with high temperatures and intense punctual rains, the use of a roof with a single layer tensed cone allows the new functional use of the courtyard for cultural events by protecting it against the sun and the rain, as well as facilitating enough ventilation to reduce the effect of the high temperature • The final costs of the membrane incorporation estimated in €/m2 were: 450 for the ETFE cushion and 220 for the one layer cone