The disadvantage of a post-tension slab is that it tends to deflect more than a conventional slab. In addition to requiring more concrete, it also requires more reinforcement. This type of construction is ideal for a frugal floor design, because it minimizes the need for columns. Its advantages include a low cost of maintenance due to cracking and durability. In addition, it is easy to adjust the tensioning in order to balance the deflection and keep the structure stable.
Another advantage of a post-tensioned slab is that it requires less steel than a conventional slab. Conventional concrete slabs require 5 to 7 lb. per square foot of steel, whereas a post-tensioned slab requires only two to three lb./ft2 of steel. The formwork used for the slab can be removed immediately after stressing. It can be moved to a subsequent pour without any problem.
A major disadvantage of post-tensioning is that it makes it harder to make complex designs and curves. As a result, post-tensioned slabs are more prone to corrosion and accidents, as they are often improperly installed. The tensile strength of the concrete and steel tendons are directly related. As a result, they have a higher load-bearing capacity.