İSTANBUL'DA YİRMİNCİ YÜZYIL ERKEN DÖNEMİNE AİT BİR APARTMANIN CEPHE KORUMASI

Rehabilitation of historic buildings demand not only an understanding of current requirements and designation of appropriate contemporary uses to the buildings, but also a careful survey of history of uses, a thorough knowledge of the past construction materials and implementation techniques, as well as the intermediate forms of intervention in these buildings. The task of rehabilitation requires therefore the collaboration of numerous specialists in distinct areas of study. The subject involves historians, architects, engineers, building scientists, chemists, materials experts and others, and all operations need to be based on coordinated work. As cases of such integrated implementation are not abundant, reporting and publication of such experience are highly valuable. The case of 'Maçka Palas* provides sufficient evidence for the relevance of such an integrated approach to historic building rehabilitation. The Palazzo Matchka as it was originally named, is a reinforced concrete apartment house constructed by the Levantine architect Giulio Mongeri who lived in Istanbul and was well-known with his 'Young Style' buildings. Maçka Palas was erected to serve the Italian Embassy for the accomodation of their guests and officials. With the foundation of the Turkish Republic however, as all of the embassies moved to the new capital Ankara, the embassy building and its ancillary accomodation buildings in Istanbul were abandoned. The embassy building was purchased by the state to be used as a senior high school, whereas the Maçka Palas was bought by a Levantine citizen. Between 1923-1990, the flats were rented by famous politicians, artists, and sportsmen who dwelled there for years (Figure 1). In 1994 the building was bought by the Doğuş Holding, reconstructed and reused as the headquarters of its banking activities (Figure 2). The design and use of materials also unravel an interesting history. After the second half of the 19th century, artificial stone mostly replaced the use of the natural stones in building. 'Revival' or 'eclectic' architectonic forms of the facades were produced either by using cast stone, or shaped by plastering techniques. During this period different techniques concerning artificial stone were used, based on cement binders with various coloured aggregates and dyeing components. Such formulae were enriched by means of inorganic and organic additives (Lewin, 1966; Pasley, 1997 /1838; Vicat, 1997 /1837). After the invention of the Portland cement by Joseph Aspdin in 1824, cement was extensively used for the production of artificial stones. Various hydraulic cements were invented in Europe and USA in the following decades, which were patented in the building materials market of the 19th century. This has led to the establishment of many artificial stone workshops and factories in the first quarter of the twentieth century. Late 19th century and early 20th century housing architecture of Istanbul favoured the use of such artificial stones. The formulas for these artificial stones were imported by architects of European origin or of Ottoman ethnic minorities who were employed in Istanbul. Artificial stone was manufactured either as cast stone to be used as masonry blocks, or plastering techniques were applied in several coats. Today artificial stone is an object of historical significance to be conserved, and the original recipes are scientifically investigated. All of the plastic repairs in Maçka Palas were therefore preceeded by scientific research, which included the characterisation of the original materials and the determination of their physical and mechanical properties. This meant to obtain the technical data for designing and preparation of mixtures for repair mortars. Qualified labor was necessarily employed for the repair works, as poor workmanship distorts the decorative forms into false images, and degrades historic buildings. The physical properties of the repair mortars such as porosity, water absorption (by weight), coefficient of capillarity, drying rates, water vapour transmission, coefficient of linear expansion, as well as the mechanical properties should match those of the original components or parts to be integrated. Another concern here is that the repair mortar itself should not cause any chemical corrosion in the old fabric. Architectonic forms of the facades of the Maçka Palas were designed and created using artificial stone-. Ornamented artificial cast stone blocks were used in the walls, alternately with the brick courses. The ashlar imitations were formed using plastering techniques. The prevailing colour of the facade was obtained by using a pale grey cement as the binder mortar, most probably animal glue, turpentine, and mixture of yellow and red oxides were impregnated for repelling water and for general protection from weathering. Impregnation of this mixture has turned the colour of the facades into buff-grey. Balusters of the French windows were brownish pink due to the pigments which were used in the original recipe. Other decorative reliefs were creamy-white, yellowish brown or red in relation to the dyeing additives used. Also marble textures were created using painting techniques on plaster work for decorative purposes on the parapet walls of the windows.