A deadbolt differs from a mortise primarily in design, construction, and installation (basically everything!)
Deadbolts are generally standalone locks that are installed separately from the doorknob or handle. Mortise locks, on the other hand, are integrated locksets that combine both the lock and the doorknob (or handle) in one unit. It requires a rectangular pocket or mortise to be cut into the edge of the door, hence the name “mortise lock.”
In general, most door locks in Singapore HDBs are mortise locks. Some condos may feature deadbolt locks – these are usually accompanied by long handlebars.
For more information, check our article on U100 vs the rest of the lineup.