Does flame finishing granite reduce its strength?
Flame-finished granite has a lower flexural strength than granite that has not been flame finished. Spalling and microcracking on a flame-finished surface reduces the effective thickness of the granite panel by about 1/8 inch. The actual reduction varies, based on the flame-finishing machine. The temperature of the flame, the speed at which the stone goes through the machine, and the angle of the flame jets all can affect the depth of the spalling and microcracking. On thick stones (1 inch or greater), such as monuments, flame finishing only creates a different texture. Any strength differences shouldn't matter.