Roofs אדריכלות ישראלית Architecture of Israel #133 May 2023 | | 36 food for thought roof beams, attics and all the rest Eli Leffler The term "roof beams", which has always been identified with a house, highlights construction technology as a condition that dictates the nature of the building, focusing on the most effective way of carrying the roof load over the walls. And not in vain - constructing a roof has a decisive affect on the entire building, from the foundation to the roof canopy’s properties’ method of construction. It is worth mentioning that the most significant leap in the evolution of the history of architecture was the invention of reinforced concrete in the mid 19th century - a construction method that reshuffles the deck, bypassing geometry by utilizing concrete's resistance to pressure on one side, with steel's resistance to expansion on the other side. This actually was the first step in blurring local identity, which traditionally reflected the availability of construction materials and the production technologies handed down from generation to generation. The main explanation for this is that concrete can be obtained everywhere, and due to the fact that concrete largely reduces the dependence on the strength of the material, its thickness and its geometry, with almost complete dependence on traditional methods, such as arches, vaults and slanted roofs, the architectural significance becomes mostly aesthetic. Until then, adjusting to the environment, dependant upon local materials and construction culture handed down from generation to generation, the most common methods of roof support were the arc, the vault, the dome and the sloping roof - all based on material and weight savings (similar to bridges) in order to ease construction. In this regard, it is worth noting that, in contrast to the constructive logic of the method based on reducing the need for supporting beams via geometry, many of those who deal with construction (including some civil engineers) do not internalize the point, and add needlessly, in the case of concrete beams, loading of unnecessary weight on the structure. No less strange is the fact that in recent years, with officials taking control of entire building planning via anachronistic Master-Plans and local space guidelines, tiled roofs invented thousands of years ago are even today unreasonably regarded as a leading roofing method. Here it is worth mentioning that, unlike the Latin ceramic tile roof that allows for a relatively moderate gradient, Northern European tiled roofs have been based mainly on shingles, especially suitable for sharp slopes to prevent snow piling and capillary osmosis, where water rises up the mantle, defying gravity. This was made possible with the coming of the industrial revolution, which began to massively produce handmade tiles relatively cheaply, the most prominent of which were Marseille, Cyprus and Israeli tiles, and even concrete ones, largely reducing their cost. Different variants of tiled roofs have been documented for over five thousand years all over the world, and they were also common in Israel until the seventh century Arab occupation that brought with it the alternative use of domes, arcs and vaults. The renewed use of tiled roofs returned to Israel with the crusaders, though the most influential were the Templars, who arrived from Germany in the late 19th century, adapting to local climate conditions, while creating rural communities, the most prominent were the colonies; Sharona, Wilhelma, the Bethlehem of Galilee, as well as the German colonies in Jerusalem, Zichron Yaacov and Haifa. Roofing on wood construction includes collar (horizontal) beams, slanted collars, joists, crowning and lockouts. If the roof is clad with shingles they are generally laid on plywood. The question is, why do people tend to adopt the tiled roof as an aesthetic model even though it is known to be an old, anachronistic building method? The simple answer is that, because the human brain tends to perceive the environment through visual models, there is a tendency to adhere to everything perceived as effective, proper and correct, even when it is no longer relevant (such as the old -fashioned facsimile that refuses to move from the world mainly among legal and financial institutions). . The problem is that this is manifested in oldfashioned Urban Master plans and Spatial Guidelines written by those who lack any basic understanding of architecture, often
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