Precast parking structures are subject to sub-structure concrete deterioration due to the high number of control joints. Typically constructed with double tees and inverted tee beams supported on cast-in-place or precast columns, the structural pieces are cast off-site. These pieces are then erected by a crane-supported construction crew. At the intersection of each precast piece is a control joint. Original construction detailing usually includes installation of an elastic caulking system to seal the joints from water infiltration. However, there may be problems with the caulking system that lead to failure: the caulking may be poorly installed; thermal movement at the joint may overcome the caulking elastic properties; or the caulking degrades due to sun exposure, traffic wear, and poor maintenance practices. Water infiltration of these joints initiates corrosion in the reinforcing steel at critical structural areas. This leads to expensive concrete repairs.
Older precast parking structures may have a concrete topping field cast on top of the double tee system. Some precast suppliers currently provide pre-topped tee systems. In either case, the concrete deck is subject to deterioration from many factors such as environmental conditions, salt application rates, traffic counts, and original construction quality. Urethane traffic membrane systems, when properly selected and installed, can protect parking structures from water infiltration and concrete deterioration.