Hammers - 20 Any building material
32 Levels Max
Land near Road
Apartment's can be built up to 32 levels per tile, depending on the material. Each Apartment makes one job and each level provides space for 4 citizens to live. This means a 4 level apartment supplies 16 citizens, or 15 productive citizens as one citizen per Apartment will be a janitor.
It is important to remember that too many apartments will result in cramped living conditions and cause a happiness penalty. This will show up the mail moral report (-3 cramped living conditions too many residents that are not apartments) while it is desirable to build apartments and condominiums for space and time reasons remember that there is a trade off. To avoid this build more houses or when an abundance of materials are available build condominiums.