D1 Earth roofing. Syria 1/5 PRÉSENTATION. Geographical Influence. Definition

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1 Building techniques : Country : D1 Earth roofing Syria PRÉSENTATION Geographical Influence Definition Earth Roofing - Roof with very weak slope covered with one or more layers of earth or mixture of earth, organic elements or lime. - The roof rests on a floor of wood, or sometimes on one or more vaults. - The blanket is compacted, and sometimes rendered with a lime wash to improve its waterproofing. - The vulnerability of earth to bad weather requiring constant maintenance, this technique of roofing, gradually given up, is on the verge of disappearing. Environment In the MEDA area, earth roofings are generally present in plain rural environment, common except in Spain. In Syria, earth roofings are generally found in rural environments, mountain and plain, especially in the costal area around Lattaqquié. General view: Detail close-up: 1/5

2 CONSTRUCTION PRINCIPLE Materials Nature and Availability (in what form) The roofing consists of a compacted blanket of one or more layers of nearby extracted clayey earth, sometimes mixed with organic elements (plant or animal) or with lime. In Syria, the binding material: ready-mixed mortar with earth extracted nearby. Clayey earth is preferable for good waterproofing. This earth is mixed with straw. Modules, Dimensions, Thickness, Dosages The total thickness of the blanket varies from 7cm to 40cm, the common thickness being between 10cm and 30cm. In Syria, the total thickness of this roofing varies between 30 and 40 cm. Dose ratio: 75% earth mortar and 25% straw. Type of laying Type of laying Type of laying the blanketing is carried out by spreading out the earth or the mixture in one or more layers over a bed of branches, leaves or algae, or directly over the floor or the masonry support. The earth (or mixture) is then compacted to ensure the waterproofing of the blanket. In Syria, standard construction laying principle: Cob processing (clay and straw mortar): The last layer of the wooden structure is made with burnet or leaves. The cob is prepared on several layers; each layer is packed with a stone cylindrical roller, with a wooden board on each side, rolled over the surface using a piece of rope. Associated framework The roofing generally rests on a wooden floor, sometimes on one or more vaults. In Syria, the ceiling rests on the walls and a stone or wooden post, circular or square, called " Al Samouk ". The structure of the ceiling is made of a horizontal main beam, pressed on the joint post and the opposite walls, of secondary beams perpendicular to the main beam. Above these beams, a perpendicularly row of reeds is laid. Construction principle: general view Drainage Adapted slope (%) The slope, extremely weak, generally ranges between 1% and 5%, except in Morocco where it can be stronger. In Syria, slopes: these slopes are weak, about 1-5% in several directions. Water collecting and drainage: gutters are placed according to the direction of the slopes to channel rain water. Water collecting and drainage The slope is sufficient to allow water run-off, whose evacuation is ensured by gutters or waterspouts, except in Egypt. In Syria, the ceiling is against the walls, sometimes protruding to avoid rain water run-off. Processing of specific points (bargeboards, runoff, neck gutters, ridge sheathing...) The roofing has a homogeneous surface. Sometimes, the edges are subject to specific works (acroters, eaves...). In Syria, nothing specific reported besides Mediterranean commentary. Construction principle: details close-up. 2/5

3 CONSTRUCTION PRINCIPLE (CONTINUED) Tools Specific tools are often used for the compaction of the earth. In Syria, the tools used are: - a sieve called " Al Sard " to sift the earth. - a small roller called " Al Marjliné " to spread the cob. - a tool to mix the earth and water (shovel) Trades Trade, Nombre of people necessary Earth flat roofings are often implemented by the builder (mason), sometimes helped by the owner or neighbours, when it is not the owner himself who carries out the work. One to six people at least are mobilized, according to cases, for these works. In Syria, a mason carries out this process, and the inhabitants take care of the maintenance. Performances Construction principle: side view Waterproofing, Protection against bad weather The resistance of flat earth roofings is generally weak, for snow, rain and significant hygrometrical variations (periods of drought) causing a crackling of the clay. In Syria, the waterproofing is poor and unreliable. Likewise, protection against the rain is poor. Thermal insulation Because of its insulating capacity and the strong inertia of clay, flat roofings in earth offer good thermal performances, provided the ventilation of the roof is sufficient. In Syria, the thermal insulation is good thanks to the thickness of the ceiling, as long as the ventilation is adapted. Ageing pathology Linked to materials and climatic conditions : The low mechanical resistance of clay contributes to its vulnerability to rain erosion; this material is moreover extremely sensitive to hygrometrical variations, causing cracks in dry weather. In Syria, diseases related to materials: cracks appear because - Use of bad earth - Poor sifting of the earth which doesn t discard gravel in the mixture, causing cracks to appear because of weather aggression: rain, dryness and sun blaze. Construction principle: tools. Linked to the technique : A bad compaction, an insufficient thickness of earth, and an irregular slope not ensuring a good water run-off, can hamper the waterproofing of the roofing. In Syria : - Bad compressing of the cob. - Insufficient thickness - Poor processing of the slopes, causing water pockets - Irregular final surface, causing water pockets in certain places and infiltration through the ceiling. Drainage, associated elements 3/5

4 CONSTRUCTION PRINCIPLE (CONTINUED) REALISATION DESCRIPTION The realization of works must be done in dry weather, to avoid rainwater infiltrations; no particular protection is necessary. Clay and, in certain cases, the materials necessary for the preparation of mortars or the various layers are supplied. Sometimes, clay is sieved to remove impurities, before being mixed with water, in certain cases, with straw or aggregates. The frame must be sufficiently clean. A good ramming or compaction of the earth or mortar is essential for the waterproofing. One can check the waterproofing of the roofing by sprinkling it, in order to detect possible water infiltrations. In Syria : After preparing and sieving the earth, mortar mixed with water and straw, then spread out over the roof in several layers. Packing with the abovementioned roller and slope shaping in several directions of the building. Tinplate gutters are placed on the roofing, at each slope end, to recover rain water. In rural areas in the north of Lattaquié, one uses an insulating material called "Al Kairak" spread over the final surface. Maintenance: It is carried out yearly. With the appearance of cracks after dry or sunny periods, the surface is sprinkled with water and packed again. If there is a deterioration of the roofing layer or if thickness becomes insufficient, cob is added, spread and packed as usual. 4/5

5 USE, EVOLUTION AND TRANSFORMATION Use Types of buildings Flat earth roofing on all types of buildings through the MEDA area. In Syria, roof for rural houses. Period when technique first appeared: very old, as far back as 1300 BC. Period when the technique first appeared / Period of use of the technique - contemporary or disappeared. The appearance of flat earth roofing is generally very old: it goes up at the Neolithic era in Jordan, in the Middle Ages in Spain, and later, in the XVII century (Ottomane period), in Palestine. The technique of flat earth roofing practically disappeared, except for Greece where it is on the verge of extinction, and in Morocco where it is still in use. In Syria, this technique disappeared following the emergence of modern building materials, easier to use and ensuring better waterproofing. Reasons of the disappearing or the modification of the technique The technique of flat earth roofing practically disappeared, because of the low resistance of earth or the earth mortar to bad weather, requiring constant maintenance, sometimes even periodical total repair. In Syria, nothing specific reported besides Mediterranean commentary. Evolution / Transformation The materials Flat earth roofings are gradually replaced by slabs of concrete or other waterproof roofings, and sometimes by inclined roofs covered with tiles. In Syria, cement substituted earth. The technical aspects The laying of a waterproof film (bituminizes, nylon...) between the support and the blanket, makes it possible to correct faulty waterproofing of an earth roofing. This technique is especially used in Greece and Spain. In Syria, nylon is used as an additional material for waterproofing. A layer of branches is added above, before the final layer of cob. Evaluation of materials and replacement techniques The replacement of earth by cement or concrete has many drawbacks: these materials are not very compatible with traditional wooden floors, their level of thermal insulation is reduced, and their esthetics are poor. On the other hand, the laying of a waterproof film between the support and the blanket is a satisfactory solution to compensate faulty waterproofing of earth roofings. In Syria, cement or concrete substituted earth. These roofs do not ensure good thermal insulation and are ill-adapted aesthetically for rural buildings and environments. They do not adapt well to wooden elements, but do ensure good waterproofing and protection against rain. 5/5