I think insulation in all the walls and the ceiling would make it more sound proof. That can be installed by the residents themselves if it is their own house and they know how and have the money and time to tear walls apart. It seems they don't make houses and apartments as high quality here as they used to. Now it is thin cheap wood. To consider that the construction methods in the Roman and Egyptian empires were superior in longevity and stength than today's construction methods. It's kind of sad really that it has been down-graded in that way these days.
Eh, only the public buildings (partially) and palaces were of the quality you're thinking of. The normal people in cities lived in a fairly dangerously built shacks piled on top of each other to form apartment buildings (or tower blocks if you wish, though the amount of floors wasn't quite as high as in present days). There are barely any remnants or even ruins left of those, just the high quality stuff. Same largely applies to all ancient civilizations; mainly the monuments have survived, because they were made to survive.
Of course, the buildings that have survived - plus the roads and aqueducts - those were quality engineering all right. The largest dome built of non-reinforced concrete belongs to the Pantheon...
If I were sent back in time to ancient Rome, I'd try and teach them how to use
reinforced concrete and see what they would come up with that. Now that would be interesting, because it would give them incentive to industrial steel production, which would probably make them find an use for the silly Greek toy called steam turbine.
If games are so much fun.
