Lift slab construction is a method of constructing concrete buildings by casting the floor or roof slab on top of the previous slab and then raising (jacking) the slab up with hydraulic jacks, so being cheaper and faster as not requiring boxing and supports for casting in situ.
The method was first used at Trinity University in San Antonio, Texas during the construction of Northup Hall in 1952.
Johnstone Hall, a Clemson University dormitory in Clemson, South Carolina, was erected using this method in 1954, as did Woodrow Wilson High School in the same year. Several of the blocks from Johnstone Hall have now been demolished, and campus legend says that two other similar structures built elsewhere collapsed before completion.
Lift slab construction was also involved in the L'Ambiance Plaza collapse in Bridgeport, Connecticut, in 1987, and resulted in a nationwide federal investigation into this construction technique in the United States, and Connecticut imposed a temporary moratorium on lift slab construction.
A patent was issued to Tom Slick for this construction method, called the "Youtz-Slick" method, in 1955.