«CSAAR (7: 2010: Amman) Sustainable Architecture and Urban Development \ Edited by Steffen Lehmann, Husam Al Waer, Jamal AI-Qawasmi. Amman: The Center ...»
The Atlas Mountains divide Morocco not only geographically but also in lifestyles and in architecture occur, along the Draa Valley, in fact, among the palms, there are over 300 ksur, berber villages constructed entirely with raw earth. These village, rural and fortified, are characteristic of the Dräa and Dades Valleys and date from the fifteenth century, period when the sedentary Berber population was the need to elose the vilJages with high walls and defensive towers, caused by the continuous attacks of the nomadic Berber tribes. The ksur (sing. ksar) have a very den se urban fabric, with houses buHt each against other in order to defend each other from the warmth, in addition, often the first floor is constructed on bridge on the road, thus creating, below, a fresh and dark tunnels Sustainable Architecture and Urban Development grid, that protect from heat and sand storms (Baglioni, 2009, pp. 22-34). It is interesting to see how this type of aggregation simulate the underground architectures, enjoying the advantage ofthermal insulation and, at the same time, solving the big problem of ventilation (Bourgeois, 1988, p. 48).
In addition to ksur, the Valley is spread with kasbah, big fortified houses belonging to berber families who protected the villages and adjacent territories, or, later, belonging to the representatives of Pasha Glaoui, who exercised administrative control until the Morocco independence.
Figure 3: Kasbah Dar EI Hiba into the Tissergat ksar, Draa Valley, Morocco.
(Credit by Baglioni E., 2009) Both in the kasbah and into the ksur, the housing type used is constant and recognizable, is a patio house. This type, with its specific and different models, has spread not only throughout Morocco, but throughout the Arab World and the Mediterranean. The patio is typical ofthe Arab-Muslim housing and is identified with the centre and the heart of horne and family life; it's a place to live, active, but at the same time intimate and collected. In the Dräa Valley building, the patio isn't just a vertical hole in the building, but it's defined by a perimeter gallery present at all floors, which creates a trading plan between the central vacuum and the private rooms; the patio size and shape are determined partly by local building techniques and climate and partly by the Iocal traditional culture.
232 Eliana Baglioni The importance of this space in the housing composition is also expressed in the architectural details and decorations, that are very rich compared to other walls where there aren't specific details (Baglioni, 2009, pp. 38-43 & 51-55).
Figure 4: Internal view of a patio in Tissergat ksar. (Credit by Baglioni 2006) Thc typical plant ofthe house, ca lIed dar, prescnts thrcc wall square inscribed one inside the other. The largest is the perimeter of the house, the smallest coincides with the central patio characterized by arches that rest on 2, 3 or 4 pillars on each side. Thc intermediate square corresponds to the wall separating thc rooms from the distribution arca around the patio; the scale is in a corner of the room area. The dar are generally constructed on 3 floors. The ground floor normally hasn't housing function except the centrai patio which, if covered, is used as a summer living room, being fresh because it isn't invested by direct radiation, and as a warehouse or storage room in the winter. The rest of the rooms housing traditionally stables, agricultural equipment and non-pcrishable domestic reserves. The first plan, called assfalou, i1's more private and reservcd for women, shows the kitchen, the bedrooms and the storeroom for the food reserves, this part of the house is forbidden to the strangers of the family. The second floor back to being enjoyed by the guests and has direct aceess from the stairs, without erossing the assfalou. This plan has a eovered part, where there is a living room ealled mesria, and a big terraee that is used to sleep on summer nights and to perform other household aetivities. The terraee is always surrounded by high walls, to maintain privaey from neighbors. The house looks modest, but hospitable and adapts to the need of a pe asant soeiety, onee nomad, subjeeted to a hostile climate (warm and dry) in whieh the temperature ehanges, both diurnal and seasonal, are very marked. For these reasons, the spaces haven't a great speeialization, the same room ean be used as living room, dining room or Sustainable Architecture and Urban Development bedroom, depending on needs and circumstances; the people practice the daily or seasonal nomadism into the house, wh ich consist to live in different times of the day or of the year in different rooms of the house, to enjoy the best possible comfort conditions (Bounar & Chahid, 2004, pp. 46-47).
We can already see how these houses are sustainable, in the broadest sense, because responding at the housing needs and respecting the local culture cIosely Iinked to the nomadic life, link that is reflected necessarily in lifestyle and in the space occupation.
high (can reach 6 floors), and presents towers in the corners. Belong to large families, powerful and wealthy, often the kasbah are more articulate and occupy large areas by combining several central patio buildings. The kasbah is thus divided into different areas, private or publicly, available for the various members of the family, servants or guests, and with distinct uses (Anzalone, 2005, pp. 71-83; Biondi, 2005, pp. 157-169; Caltabiano & De Filippi, 2005, pp.
93-106; Lucci & Dania, 2005, pp. 133-144; Marrani, 2005, pp. 107-118;
Sänchez, 2005, pp. 119-131).
In the Draa Valley, characterized by a pre-desertic climate, the use of patio houses and a compact urban aggregation, represents an effective response to weather conditions, creating thus a sustainable urban system. The basic principle of buildings adaptability to the extreme temperatures is that the buildings are such that allow the highest possible ratio between the internal volume and the outer surface, condition that occurs in the ksur of southern Morocco (Abdulac, 1982, p. 2). In the ksar aggregation system, in fact, the outer surface, exposed to the sun, is limited by the adoption of buildings constructed each against other, so to have common perimeter walls on each side, except the entry side at the ground floor. At the same time, the patio is a key element for lighting, ventilation and to maintain comfortable conditions.
The patio functions as a shaft of light, limiting the direct insulation of the ground floor: all rooms of the house facing it and receive indirect light. The house is almost completely closed, only rarely found windows on the ffee extern al walls, but never on the ground floor to ensure privacy and confidentiality. The windows are quite small and shielded from wood or metal gratings, called musharabia, that filter the strong outdoor light and limit the interior visibility, however, ensuring the cross-ventilation. The patio also has a ventilation function: like a chimney pulls up the warm air contributing to the rooms cooling and creating a pleasant ventilation.
Figure 7: Patio climatic behaviour in the summer. (Credit by Baglioni E., 2009) Sustainable Architecture and Urban During the summer, the patio dimatic behaviour can be summarized in 3 regular cycles that exploit the diurnal variations in temperature, higher in the pre desert dry hot elimate. In the first cyde, the cool night air descends on the patio until enter into the around room. All surfaces are cooled and are able to maintain it8 temperature nearly constant until the late afternoon. The patio and the roof lose, by irradiation, the heat accumulated during the day, and for this is also uscd for sleeping. During the second cyde, trom morning to early afternoon, the patio is invested directly trom sunlight, heat and gradually spreading warm air into the rooms, created so a convections motions. The patio begins to work as a chimney, drawing the fresh air replaced by warm, yet create the "breeze". Ventilation can be increased by the presence of some windows on the upper floors or, more often, opening the entrance door to let enter the cool air of the tunnels roads. The outside temperature is very high, but the thick walls (60-80cm) and roofs (40 50cm) made with row earth are excellent thermal insulators and don't allow penetrate the extern al heat into the house, the displacement between the extern al and internal wall temperature can reach 12 hours. The houses also being leaning each against other and having common walls on at least 3 sides, would be further isolated trom the heat gain during the day. In the third cyde, during the afternoon, hot convection currents increase due to the heat accumulated in the earlier sunny hours, and in the late afternoon, fresh air has been expelIed almost completely trom the rooms. But outside the sun i8 weaker, the shadows are longer, temperatures begin to fall and cooler air begins to flow and get into the patio. Begins a new cycle (Al Bena'a, p. I).
Let's see how, with some typological devices, is possible respond, in an effective and sustainable way, to the comfort living needs, evcn in hostile climatic conditions, especially without thc use of energy expenditure. But an effective building type, if not accompanied by an appropriate choice of construction materials, often alone is not enough.
2.2 The Draa Valley earth building techniques (Morocco) In the traditional building technique ofthe Draa Valley, the major role is played by the earth material, used in many different situations, which proves to be the most suitable material for an effective response to warm dry climate of the place.
The masonries techniques used are the rammed earth, called al1euh, and the mud brick, called toub, used separately in different parts of the building.
Although this techniques are known and spread throughout the W orId, their implementation demonstrates a local cleverness which allowed at the population to adapt and protect themselves against the toughest aspects of the pre-Saharan climate.
The rammed earth 1S a technique that consist to compact layers of damp earth in a wooden formwork. This technique allows realize a very tick (40-100 cm) continuous bearing walls. The masonries runs proceeding horizontally until the 236 Eliana Baglioni completion of the entire perimeter, after an appropriate drying time (depending on climate, but not less than one week), necessary to prevent deformation or collapse ofthe wall, goes to realize the high er level; the building is then lifted for later "layers". This construction system performed by shifting one formwork, block to block, involves the adoption of an almost constant thickness of the wall along the perimeter and, generally, even over the whole height. As for masonry buildings, particular attention should be in the scarf realization to ensure mutual collaboration between the blocks, between walls or between wal1s and partitions.