Roof Tiles — Thermal Expansion
A fired roof tile was exposed to water for 24 hours and then tested with the DIL 402 C between -20°C and 25°C.
Upon cooling, the water in the poresof the ceramic body freezes at -7°C. (The low freezing temperature is due tosuper cooling of the water.) The freezing causes an increase in the sample length of nearly 0.08%. Upon heating, the ice begins melting at -2°C, resulting in a shrinkage of the sample.
The irreversible length change of the sample after cyclic cooling and heating may be partiallydue to cracks. The use of this roof tile type in certain climate zones should be given careful consideration prior to installation. Freezing effects will reduce its lifetime.