Floors
In order to meet all sanitary requirements the “floors must be secure and proof against air, dust, sound, vermin, fire and water.” But it is not often that the floors meet all these sanitary demands. Ordinary floors are made of hard boards tongued and grooved, tightly fitted and laid upon joists placed about one foot apart; the under surface is lathed and plastered to form the ceiling of the room below, or some sort of patent ceiling may be used. However, there is great objection to the space thus left between the floor and the ceiling, as it becomes a receptacle for dust and greatly endangers the spread of fire.
It is better, according to sanitary demands, to have the floor of reinforced concrete, or the space within filled with mineral wool or asbestos; or the floor may be made of steel beams encased in terra-cotta with interspaces made of concrete.