Environmental Impact of a building's roof with a garden

Order Details;

GARDEN ON TOP OF THE ROOF.

A normal 4 floor building with empty roof – the roof will be converted into a nice garden with flowers and bushes.
Undertake an environmental impact of that building before and after the conversion.
Assessment of the environmental impact of the garden when placed on top of the roof using a scoping matrix.
The building’s roof is with sizes 25 meters long with 55 meters wide.

Present data of the impact before and after and why is this impact taking place.