Laundry treatment apparatus and method of controlling the same

A laundry treatment apparatus includes a cabinet having first and second washing apparatuses that treat laundry introduced through a front opening and through a top opening, respectively. The second washing apparatus includes: a tub that holds water and has an opening at a top that is accessible through the second opening; a drum inside the tub that rotates about a vertical shaft; an agitation unit protruding upward from a center bottom surface of the drum that agitates water and laundry inside the rotating drum; a heater that heats water in the tub; a water supply valve controlling a flow of water into the tub; and at least one processor that controls the heater to heat a first amount of water in the tub to a first temperature; and controls the water supply valve to additionally supply, to the first amount of water, incremental amounts of water to into the tub.