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.

Two traditional wooden building systems in ()

Michela Dalprá Antonio Frattari

Lying in the heart of the Alps, Trentino covers an covered with wooden roofing-tile (shingles). Today area of 6 thousand 200 square kilometres. A thick the shingles are replaced improperly with tiles and hydrographic system crosses the Trentino and sheet. originates a complex system of vaIleys that are The constructive techniques used mainly for the densely populated. Because for geographic position construction of the traditional rural buildings, between northern Europe and the Mediterranean, emerged from a research carried out in the Laboratory Trentino has always been a land of encounter and of Planning Building Design of the University of exchange among the populations, as its history and Trento in order to identify and cIassify the typologies interesting traditions show. An Alpine climate of wooden buildings are the blockbau system and the characterizes, nearIy everywhere, the territory that framework system. is mostly a mountain landscape and it is covered with abundant forests where predominate broadleaf and conifers species that produce optimal timber. THE TRADlTIONAL RURAL BUlLDINGS IN TRENTINO The Trentino landscape, so rich of orographic, hydrographical and material resources, has been an Specific typologic and constructive peculiarities ideal scenery for the initiatives ofthe constructor man characterize the traditional building of the Trentino. that was able to use the riches of the area and to These peculiarities make different the Trentino's colonize in the best possible way the territory. traditional rural heritage from that of other regions. In The abundance of wood has favoured in the past a Trentino there are many wooden buildings and many very great use of this material for the buildings buildings in wood and in masonry that meet dweIling construction and for buildings parts construction. and rural requirements. They have the function In the traditional rural building, in fact, the wood, to shelter people, animals, tools, and to preserve often is matched to the masonry. In Trentino the agricultural products. In many areas these service combination of masonry and wood in the buildings is rural buildings are separated from the building where variable according the areas and according to the the countrymen Jive. They are buildings independent, building typo]ogy. In the traditional rura] service seasonaJ, placed at different heights according the buildings the masonry, generally, constitutes the activities to carry out. At the middle and high heights basement, while the other floors and the roof structure it' s easy to find building s with the cowshed on the are wooden. Traditionally, in many areas of the ground floor and the barn on the first floor. Generally Trentino, the roof lining was wooden. The roofs were al! these constructions are directed according the 678 M. Dalprá, A. Frattari ground slope: down there is the entrance to the The wood was the optimal material for the barn in cowshed, above there is the entrance to the barn. order to obtain a good aeration and in order to prevent Different are the names used in Trentino for the the hay fermentation and its spontaneous combustion. traditional rural service buildings divided into cowshed The wood was easy to find in the rich forests of trees and bam. In the Giudicarie valleys (south-westem that there are in Trentino. The mainly used species Trentino) the buildings placed at the middle and high were the larch (Larix decidua) and spruce (Picea heights to shelter animals and to preserve the hay are abies). The larch is much resistant to the action of the called «ca'da mont». In the Fiemme and Fassa valJeys atmospheric agents and it has good physico-mechanic (north-eastern Trentino) these building s are called characteristics. The spruce has characteristics similar «tabia». In others areas Jike in the Sole valley and in to the larch, but it is not so resistant to the atmospheric the Rabbi vaJley (north-western Trentino) are calJed agents than the larch. The spruce was preferred for «masi». In some areas of the Trentino, in the Mocheni inner structure and inner coating. valJey for example the name «maso» indicates a multi- From a study on the typologies of the Trentino's floor building where the people live and work, where rural buildings are emerged two constructive the dwelJing and rural functions coexist. Here the techniques for the construction of wooden buildings: «maso « is a family farm whit the house, the the Blockbau system and the framework system. The surrounding land and the agricultural equipment. framework system presents two variations: the «ritti e The material s used for the construction of the «ca' panconi» system and « a crociera» system. da mont», the «tabia» and of the «masi» are the wood and the stone. The mixed use of these two materials defines their different functionality. The stone was The Blockbau system the more suitable material in order to construct the basement because it prevented that the wood touched The blockbau system is a typical constructive the ground. The parts in dry or mortar masonry of the technique of the Alpine regions rural building at the buildings were reaJized with natural local stone. The middle and high heights. Mainly in the Fassa valJey, mortar was a mixture of sand, local earths and lime. Fiemme valJey, Primiero's valleys, Rendena valley,

~ @ Figure 1 Different solutions of comer joint in the Blockbau system: a) the cut «a half-lap joinb>, b) removing of wood fram both the upper and lower faces of the log. Two traditional wooden building systems in Trentino (Italy) 679

Genova valleys and in Fersina valley, the wooden The second blocking system is widely ditfused in parts of the service rural buildings are realized with the traditional rural buildings of the Fiemme, Fassa this constructive technique. and Primiero's valleys in the eastern Trentino. The The walls are made of overlapping round logs, that third blocking system is characteristic of Fiemme cross in the comers. Two different solutions of comer Valleys. In some «tabia» ofBellamonte has been used joints are been used in Trentino. In the first solution this blocking system. «a half-lap joint» the upper half of the log section is The wooden floor that separates the stone masonry removed. In the second solution the wood is removed from the wooden barn is a made with wooden board s from both the upper and lower faces of the log that rest on external waJls and on beams supported (Figure 1). from one or more pillars. In order to obtain a better connection between the The roof of the buildings executed with the blockbau overlapping horizontal various elements and to stabilize constructive technique is the pitched roof. The pitches the logs on the vertical plan, in Trentino have been used are jutting. The roof, generally, has a wooden double three different log blocking systems. They are: roof frame. The large roof frame can be: a) with purJins and rafters, b) with rafters on truss, - The system that entails the interposition e) with rafters on ridgepole. The ridgepole can be between the logs of wooden dowels or pegs supported from a intermediate pillar and from pillars arranged at a fixed distance and staggered placed on the log waJls. In some cases, in place of the vertically one from other. ridgebeam, there is a longitudinal wall to support the - The system that entails the introduction rafters. In some areas, the ridgepole can be supported between the logs of wooden elements double from pillars external to Blockbau walls that rest wedge shaped. This is a system that on one side directly on the ground. improves the logs stability and on other side In the «ea' da mont» of the Chiese valley is interesting improves the aeration in the rooms. In fact the the constructive solution of external pillar blocking to wooden wedges outdistance more the logs one blockbau waJl through a curved wooden element from the other, creating openings that favour inserted between the overlapping logs. the ventilation in the barns. In the rooms where The roof lining traditionaJly was constituted from it is important that the walls are airtight, shingles, today in great part replaced from tiles and watertight, the opening are sealed with pieces sheets. The shingles are placed on joists or on wooden of musk or pieces of wooL planks. The shingles are wooden boards, 70 cm long - The blocking system constituted from two and 10-15 cm wide. They are obtained by splitting vertical wooden elements that are put in the block of larch or of spruce. In order to assure the roof appropriate holes of a wooden element placed lining impermeability the shingles are been placed perpendicularJy to a logs. on the smaJl roof frame staggered and partially

'" ~ ' ".: ~ . . a b e Figure 2 Log Blocking systems: a) system with wooden dowels or pegs, b) system wooden eIements double wedge shaped, e) two vertical wooden elementsput in the appropriateholesof a woodenelementplacedperpendicularlylo a logs. 680 M. Dalprá, A. Frattari

overlapping. In the oldest constructions the shingles were simply laid on the small roof frame and were held in position by slim logs, overlapping at intervals and parallel to the eave line which were weighted down with very large stones. After the roof lining stability was obtained by nailing the shingles. The slope of shingles covered mof is the same in all Alpine regions, about 26°. With a higher slope of the roof the snow tends to remove the shingles, with a smaller slope of the roof the mantle loses the impermeability. The door opening was created with two jambs that are correlated to the overlapping logs with tongue and groove joint. The cut log has the tongue, the jamb has the grove. The top of the jambs are fixed in the log Figure 3 that is lintel. The bottom of the jambs rests on the «Tabia» of Bellamonte in the . Traditional stone masonry basement. rural building executed with the blockbau constructive The windows are not necessarily present in the techniques. The roof frame is made with purlins and rural service buildings cowshed-barn. In several cases rafters the only openings are the doors. The windows that

Figure 4 «Ca' da mont « of Planezzo in the Chiese Valley. Constructive solution of external pillar blocking to blockbau wall through a curved wooden element inserted between the overlapping logs Two traditional wooden building systems in Trentino (Italy) 681

illuminate the cowsheds, when present, are of small cut and saw the logs and to produce planks far the dimensions. These windows in the blockbau coverings. The walls in the Trentino's framework structures are practically a simple hole realized buildings can be made with the «ritti e panconi» removing wood in two overlapping logs. The logs system or with the «crociera» system. have in height a cutting depth of one radius (until the The «ritti and panconi» system is diffused mostly center of the transverse section). in the south-western Trentino, far example in the The windows of the barn, when present, have Chiese valley (Figure 6). The walls are realized greater dimensions. They are high from three to five placing vertical elements (ritti) to regular step on the logs. In order to prevent instability phenomena of the building mesh. The vertical elements have laterally whole construction the windows have window-posts grooves in which are inserted horizontal elements that that stick in the logs with a tongue and groove joint. are placed one on the other. The horizontal elements, Balconies, overhangs characterize the facades of called «panconi», are large boards. In arder to insert many traditional rural buildings. In the Fiemme the large boards in the uprights grooves the end of the valley and in the there are some «tabia» large boards is warked with the axe. The warking that have the top tloor with a considerable overhang. irregularity on the long part of the large boards These overhangs are covered with wooden planks prevents that the large board s fit together properly. In nailed to wooden structure and create other spaces in this way there are sJits between the large boards that arder to dry the hay and to stare agricultural products favour the ventilation. (Figure 5). In some «ca da mon!» in the Chiese valley The «ritti and panconi» system could be considered the cowshed's doars are not on the fa<;ade. A space the evolution of the blockbau system concerning the subdivided in two parts called «cetine» and covered connection between vertical element (ritto) and with wooden vertical planks moves the doars back. horizontal element (pancone). The large boards are overlapping like the Blockbau logs, but in this system they don't have a supporting function. In the «ritti and The framework system panconi» system the uprights and the beams have the principal supporting function. The large boards plug The framework system is widely diffused in the the walls. Trentino' s valleys. This constructive technique The uprights are high like a floor, they are placed placed side by side and in some cases replaced the between the upper surface of the inferior tloor beam Blockbau system from 1400-1500 with the saw-mills construction and with the consequent possibility to

Figure 6 Figure 5 «Ca'da mont» of Planezzo in the Chiese valley. Building <