: Using the "Tall" wall height setting for each floor naturally increases a building's physical height. Some builders also add half-walls on the roof to give the appearance of an extra decorative level. Split-Level Construction
If you meant The Sims 3 or The Sims 2 – those have mods that increase floor count (e.g., Omegasims’ More Floors for TS3), but for TS4, the limit remains hardcoded. sims 4 more floors mod work
A tiny house experiment with eight levels of living space, connected by treacherous ladders. : Using the "Tall" wall height setting for
If the 5 floors above ground and 3 basements are not enough for you, or if you want to create a "shell" building (like a fake high-rise), there are mods that help: Omegasims’ More Floors for TS3)