Artificial turf works great for rooftops! Many residential and commercial buildings have flat roofs that are coated with a torched on membrane that is different from a traditional sloped roof that has fiberglass shingles. The result is some of these flat rooftops are actually decked areas for the people to enjoy, options are either to leave as is or put down concrete step stones or rubber tiles on the surface all of which create heat zones, artificial turf is a great way to cover these areas it gives a nice soft area to walk on, keeps the surface area easy to clean and can extend the roof life by taking all the wear and tear.
Artificial turf is 100% permeable as it has drain holes manufactured into the backing so your rooftop will drain as it always did, the artificial turf is not affected by the elements, has a strong UV and is not affected by sun and rain. If the roof ever needs repair just roll up the artificial turf and lay it back down. Rooftops with artificial turf open a lot of possibilities for increasing your livable space and should not be overlooked.