Performance tests of roofing tiles

Using a specially devised apparatus, the Trondheim Division of the Norwegian Building Research Institute has tested five types of concrete roof tiles for water tightness, using a traditional clay tile as a reference. The general conclusion is that, with the superior performance of modern concrete tiles, there is no reason why they should not be used for a roof pitch down to 15 degrees, though account must be taken of end overlaps, geometric form, tile detailing and the sub‐roof construction. The results, it is suggested, expose the limitations of present test methods, which are based on experience with traditional practices.