“Potholes” in a Mod-Bit Roof Membrane—Lichen Attack January 03, 2020 By Harvey Freeman, MNSAA, MRAIC Introduction This article describes the interaction between a naturally occurring lichen and a modified-bituminous (mod-bit) roof membrane. I have not found this topic discussed by anyone in roofing literature. The growth of this lichen is very slow in relation to the expected life span of a mod-bit roof membrane. As […] Read More