Laying slate over asphalt on roof terrace? - Slate on roof terrace

[Clake]

I have recently bought a top floor flat with roof terrace approx 8m X 5m with a stone store-room on it. There is currently excellent drainage and no pools of water remain after a rain. The surface of the roof terrace is asphalt which is slightly cracking and slightly bubbling in places at the side. We would like to re-surface the terrace and lay slate over the top (this is the floor material in the store room). Can you provide any advice on the following:
1) can we repair the roof terrace with something like bitumen, rubber instead of removing the asphalt and replacing?
2) how heavy is slate? would this be OK to go directly onto the roof terrace?

Thanks for your help, Claire

[seanandruby]

I think you need to be asking a roofing contractor to check your asphalt and a structural engineer about loading capabilities of the roof.

[Mikey_C]

^^ I concur.

[lutonlagerlout]

^^ me three
LLL