Roofing/Walling off buildings

I imagine adding roofing of some type, e.g. starting with wood planks, going through to concrete and later on being able to add solar panels on top would be another step in realism.
Currently most buildings are basically just in the open, whereas especially things like power generators of any kind are situated indoors, or at least roofed in the real world.
As for gameplay, roofing/walling off would reduce the amount of maintenance buildings need (lets say, less debris hitting a building, no water damage from rain), but themself need maintenance to keep up. Anywhere from Height 3 up to Height 6 (which would need to be added just for this) to "hold" buildings should make sufficient sense.
Possible good sideeffects this might have:
- Blueprints/Sectioning off groups of buildings is visually easier
- Demand for graphics are highly reduced if lots of buildings are physically covered (might be a settings toggle?)