Division of Building Materials, LTH, Lund University
Abstract
Summary The leaking of water through roofs is a major problem in many parts of Tunisia. As a part of a collaboration between "École N: ionale d'Ingénieurs de Tunis" (E.N.I.T.) and Lund University, Institute of Science and Technology (L.N.T.H.), Sweden, a measuring method has been developed to compare the watertightness of different roofing membranes. With the method, three roof structues with different types of bituminous membranes were tested. The measuring equipment consists of a plastic tube containing a concrete slab covered with a roofing membrane. The diameter of the tube is 30 cm and the height is 8 cm. The joint between the specimen and the tube is tightened and water is poured on top of the specimen in order to estimate the flow of water that penetrates the membrane and the slab. The tube with its specimen rests on a plastic bowl containing a bed of a wet salt with a low and well defined relative humidity. Thus, all specimens are exposed to the same type of climate and the penetration will be greatþ promoted by the big difference between the humidity above the membrane (liquid water) and below the concrete slab. The results obtained after 1000 hours of measuring were plotted in diagrams showing how much water that had run through the specimens at a certain time. The measuring method has been analysed and it has been proposed how to use the method to make it possible to calculate a quantitative value of the watertightness. Finally, an economic analysis was made in order to compare the costs of making the three roof structures
