Slow down Alex.

You are putting the cart before the horse. So to speak. Not the best analogy maybe, but the best I can come up with on the spot.

If you ask me if your mom should buy a Rolls-Royce or Chevy Spark, I would have a few questions. Like what kind of driving the car will be doing, how many people and stuff the car is expected to haul around, etc.

If you desire a number of good answers to your question you will have to give more info. Including, but maybe not limited to:

1) What is the breed or breeds of your dog?
2) How old is the dog?
3) A little info about temperment and behavior.
4) Info about your current situation, dog walks, and other activities. Example: metro area, 'burbs, .25 acre lot w 4' fence, two walks a day, gets out occasionally but doesn't go too far, is fearful of larger dogs.

I agree with Robert. What are the circumstances with the dog? Older dog who would be happy with a roof space or a young dog who needs to exercise every day?

How would this work? The dog would be confined to the roof and plastic grass all day? What about urine and poop? Will it clean up easily with no collection under the "grass?" I have heard that the plastic grass can be hot. It sounds so unappealing to me. Just my opinion, but the grass won't benefit the dog in any way.

See if you and mom can find a compromise--close enough to the city to make you happy and a place for the dog to be comfortable.

I hope we did not scare off Alex, but we really do need more info to give a good answer(or at least a opinion).

The environment the dog is coming FROM is important because it can tell us how much of a change the dog will have to accept. A Karelian living in Idaho with the nearest neighbor ten miles away is not going to be suited to a city life style. A Doodle dog moving from the suburbs might accept the change with min of fuss -- if it got two long walks a day and some play time with other dogs. A middle age dog would be preferable to a young dog of the same breed.

There is not too much chance of Alex having a Karelian, of course. But two years ago a woman brought one into the urban pet store where my dog and I were shopping. She did not have a muzzle on the dog, and it was NOT friendly. The owner claimed she just got it and did not know the breed. I double checked my dog breed books when I got home, and sure enough it was a pure Karelian -- although I could not tell if Karelian Bear Dog or Karelian Bear Latika.