What is the most common problem with slate roofs?

The most common problem with slate roofs is indeed the cracking of the tiles. Slate is a natural stone that can be quite durable, but over time, it can be susceptible to cracking due to various factors such as extreme temperature changes, impact from debris, or installation errors. This cracking can compromise the integrity of the roof, potentially leading to water infiltration and other issues if not addressed.

While failures of fasteners, leakage at the joints, and degradation of coatings can occur on roofs, they are not as prevalent specific to slate roofs. Fastener failures are more commonly concerned with roofs that use metal or asphalt shingles, while joint leakage is often more associated with flat or low-slope roofs. Coating degradation typically pertains to roofs with applied finishes rather than natural material like slate. Therefore, recognizing the prevalence of tile cracking is crucial in understanding maintenance and repair strategies for slate roofs.