Where should you put the lawn? Out front? Out back? Or up on the roof?

The roof needs to be covered in felt and a thick PVC lining. This is then covered with four to six inches of soil. This is heavy, so you do need a strong roof support in the first place.

The earth is then planted with grass. You can let wild flowers grow in it, but obviously you must root out any shrub or tree seedlings that take root in the turf.

You can lightly mow the grass once or twice a year.