Wood Structures in Traditional Random Rubble Wall Constructions in Cagliari

Proceedings of the First International Congress on Construction History, Madrid, 20th-24th January 2003, ed. S. Huerta, Madrid: I. Juan de Herrera, SEdHC, ETSAM, A. E. Benvenuto, COAM, F. Dragados, 2003. Wood structures in traditional random rubble wall constructions in Cagliari. Marco Cadinu Recent research on the residential buildings in Cagliari from late the middle ages to the first part of the 20th century, is providing more information about wall construction as we!1 as more general construction techniques. This research allows to distinguish building methods, the materials used, and the architectural models though the different periods.' One section of the present study, designed to provide a preliminary identification of vertical structures limited to non-monumental buildings, has shed some light on the quality and nature of wall construction. The most recurrent waJl typology in the row houses and in the other buildings is composed of random rubb]e and lean lime. B]ocks of tufo stone are used only for door and window frames as well as quoining. This kind of wa]] is very simple, often made with the help of sustaining structures to contain and press the ]ayers of these materials; they range from around 42-58 centimetres.2 The static properties of these walls is mediocre because they are heavy and not very resistant to tensile and shearing stress; they were best used for one or two-floor buildings, although sometimes they can be found in four or five-floor buildings. In the present stlldy we have focllsed our attention on the taller buildings.' We have observed in the wall sections the interesting presence of horizontal juniper wood trunks. In this area of research, wood in the walls had previollsly been defined as tie-beams used to repair damaged wal1s. On the contrary, evidence Figure 1 has been found that this wood represents an essential We can see the end of wal1-plate at every tloor also in four component of the original wa!1s. or five-floor building s 454 M. Cadinu The trunks were attached one to another to form a houses, it was common to use timher-frames with continuous transversal and Jongitudinal structure brick infill for partition walls. In the poorest buiJdings around the walls, making the random rubble wood was often used for lintels of doors and construction more resistant and t1exible: this hidden windows. In one instance the use of big wood beams structure is also connected to the tloor-joists. Moreover, has been documented for building the bearing sometimes we have found the presence of vertical structure wal! of the stairs in a four t100r building. wooden eJements. The typical scarf-joint is the edge- Short juniper woods were used as normal laths for halfed with a big iron pego The end of the wall-plate roofs. We found it also in planking (instead of often comes out of the far,;ade, with its wooden punch. tloorboards) or structures of stairs (Cadinu and It should be noted that wood structures had not Zanini, 1996.53). Other uses were possible. as single previously been found in Sardinia even if, in these pieces inside normal random rubble wall or as roofs Figure 2 Figure 4 A couple of wooden tie-rod used to repair damaged walls. The floor-joist structure is connected with the juniper wood (Cagliari, Marina, Scalette di Santa Teresa) trunks inside the wal1 Figure 3 Figure 5 This detail shows a simple edge-halved joint with an iron A long wall-plate in juniper attached at the comer of the wall peg used to connect long series of trunks inside the wall. A and partially rebuilt outside the wall (a second one was similar solution is used for the corners (Cagliari. Marina, found inside the wall in the same position. Cagliari, Marina, Piazza Dettori) Piazza Dettori) - - Wood structures in traditional randorn rubble wall constructions in Cagliari 455 Figures 6 and 7 A continuous structure of juniper wood trunks found inside a randorn rubble wall in a four tloors building (Cagliari, Castello, Via Larnarrnora) Figure 8 Figure 9 The bearing structure of the stairs is built with wooden Irregular verticaJ wood eJernent in support of a brick bearns (Cagliari, Castello, Via Larnarrnora) partition wall of a stone drain channel 55 centimetres of clear span.4 age period of the buiJding.6 This kind 01' structure is In order to reinforce walls, arches or stairs the use of very simple, no tension brace was used. Up until now single juniper woods is permitted in a contract of no sophisticated techniques of the fachwerk building 1786 were is written they may work «~o. putting tradition have been 1'ound. inside some juniper wood to best connect them . ».5 Ancient documents do not report information about Similar wood structures with wall construction wooden houses even jf it was observed that such a ha ve been previously reported in medieval houses in type was present in some Sardinian towns, Parma and Pisa, the latter being the founder of particularly in Sassari. A building reguJation 01' CagJiari in the 13th century. The analysis of so me 1294-] 316 describes the form of the front cutaway on middJe-age houses in Pisa have shed some light on the public street, giving the sizes 01' projecting joists the mixed nature of the walls containing a whole for each tloor. This kind 01'section is very common in wood structure, that it possible to date to the middle- wooden buildings with brick or adobe infilI.7 456 M. Cadinu lt can be hypothesised that the wood building from 3,80 to 5,40 meters of length, with diameters tradition common in the middle ages, and later between 16 and 32 centimetres. Nowadays in nature replaced by stone construction, intluenced stone trunks of these dimensions are quite rare and can be buildings in Sardinia in later centuries. Middle age 1'ound only in parks and protected arcas. «Statuti» in Sassari encourage owners to rebuild old According to our assessment of pre-industrial houses with new techniques of stone and lime (<<apetra buildings in the arca of Cagliari, at least 250,000 e a caJchina») to improve the general quality of trunks can be found. \t should be noted that these buildings in the town.~ The presence of skilled workers buildings have been constructed 1'or the most part shows the existence, even in Sardinia, of this old between the XVII and the beginning of the XX. This tradition, already common in Italy and Europe in XIII number is remarkable not only from the point of view century. Master masons and carpenters (masters «de of the historical assessment of human impact on the muru over de linna» -walls and wood, masters «de environment but also because it suggests the need for aschia»- axe), cited in the building regulations of the allernative resources in materials. «Statuti di Castelsardo» in 1336, article CCXVIl, had Although very irregular in shape, juniper possesses to receive set daily payments according lO time of lhe extraordinary characleristic in terms of strength and year (Cadinu 2001, 178). Also in the «Giudicati» durability. Its fibres, long and compact, can easily wrap period the presence of such skilJed workers like around the tmnk up until 1.5-2 meters. In spite of the «maistrus in pedra et in calcina el in ladu el in !ill/w» (stone and lime, and adobe and wood) has been reported, forexample in 1239 (Solmi 1908, 195: 393). A very interesting document dating back to 1376-77 reports the presence of a big building yard for the renovation and repair of several towers and the port palisade made by a number of stone-cutlers «picaperes», carpenters «maestres de axe» or «de fusta», unskilled workers «manobres, bastaix, macip». (Manca 1969). The public contract, registered in detail by the contractor Miguel <;:a-Rovira, contains the description of the deliveries, quantities, qualities of each material and also reports the different sizes of wood: «bigues, trapes, sostres, cabirons»: the biggest pieces carne from abroad, like 458 big poles «pals» from a place near Rome 01'big beams «fusts» from the cost of Ogliastra, east of Sardinia. 'J We think that some of the old wooden building tradition survived and perhaps a1'1'ecled the most modern building techniques. Close contacts with Spain 1'rom the 14th lo the 18th centuries clearly favoured lhe development 01' these techniques. Simple timber 1'rames with adobe in1'ilJ were indeed very common in the popular Spanish archilccture. \t\ JlIN1PER woon Juniper wood, uscd also for roof trusses and tloor- joists up unlil the beginning 01'the twentieth ccntury, can be 1'ound nowadays only in bushes. In traditional Figure 1() buildings juniper has been found in trunk ranging A limber-frame with brick infill ~~ Wood structures in traditional random rubble wal! constructions in Cagliari 457 Figure II Figure 12 The front view of a square hole built to drain waters by a A drain pipe made with piled cotto elements inside the walls. bucket directly from the highest tloors (Cagliari, Marina, This pipes drained the water to a underground family tan k Piazza Oettori) that has been dug under each building (Cagliari, Marina, Piazza Oettori) irregular structure that often causes performance complex, particuJarly in the context of restructuring decrements, the average resistance ofjuniper wood can and renovation interventions. be estimated to be more or less double to the resistance Rain waters were generally collected by drain of a pine wood. The characteristic of its resin gives the pipes made with piled cotto elements inside the walls. juniper wood its typical scent and protects it from This pipes drained the water to a underground family fungi, woodworm and white ant.

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