Painting house roof

[astra]

Anyone ever paint/seal a slate(manufactured) roof.slates on parents house are gone very shabby looking and considering painting them if it's a good job.would it help to seal the roof too?

 

[Bongodog]

I always feel that the manufactured slates look "wrong" when first fitted, too shiny compared to natural slate, once weathered they look more like the real product. I doubt you would get anything to stick to them in the long term unless the surface was well prepared, and can't see any way thats really possible, anyone who lets people pressure wash their roof needs to seek psychiatric help !!!. A roof needs to be flexible to cope with expansion ands contraction, any paint would soon crack on all the joins. Foam to the inside is a complete nightmare, ruins the slates and entraps moisture casuing the rafters to rot.