The biggest downside to slate tile roofs.
Slate roof lifetime.
These life expectancies are general experience with the material and do not consider installation or environmental factors which vary from one building to the next.
For fibre cement roof slates the life expectancy is a little shorter at around 50 60 years.
Durability and low maintenance.
Typical life for pennsylvania slate roofs is 40 50 years.
A slate roof will easily last over 100 years which is at least double of what other roofing materials can offer.
This can vary depending on the manufacturer.
Life expectancy of ribbon slates.
For people who do not plan to ever sell their home the incredible longevity of slate is a highly desirable benefit.