sorry to bother, but layer=-1 means underearth. See https://wiki.openstreetmap.org/wiki/Key:layer. "Do not use layer=-1 to hide warnings about crossing or overlapping ways. Either fix them properly or leave the easily visible warning so that others can fix them." Possible approach is to divide the building into the (main) building and projecting roof. If this path is inside the building, the approach is another. Use https://wiki.openstreetmap.org/wiki/Key:indoor, there is a seperate map for indoor view: https://indoorequal.org/