Does the geological age matter for roofing slate quality?
06/28/2016 Leave a comment
This is a recurrent question. Is “old” roofing slate better than “new”?. We know that the Earth has about 4.5 billion years (or 4.500.000.000 years). The oldest minerals retrieved have about 4.4 billion years. Compared to these ages, roofing slates are relatively young. The oldest roofing slates quarried nowadays are from the late Precambrian, “only” 600 million years ago. Some of these roofing slates are the Brazilian low-grade slates from Minas Gerais, Brazil (lithotypes B0, G0, and R0), the phyllite from Bernardos, Spain (B2) and the slates s.s. from Wales (R1 and G1). Age has then no influence on the petrology of roofing slates, neither in the quality.
There is a lot to say about quality, but I will try to summarize that in one paragraph: Quality depends on the customer requirements. Each type of roofing slate has its own special characteristics, and it is the customer who choose which characteristics are more important for him. Usually, the customer requires advise to find out his needs.
Getting back to the title of this post, does the geological age matter for roofing slate quality?
The features that have influence on the constructive requirements of roofing slate (i.e. quality) are others: Petrology (or type of roofing slate) and customer requirements, or better: What we have and what the customer wants.
I will develop this in following posts, and I promise you won’t have to wait months to read them.