The library evaluate using the former pools as landscaping, but faced challenges due to soil loads on the parking structure roof. But, observing rooftop gardens, they began to see other opportunities for reuse.
After consultation with structural engineers, the library confirmed that a roof system would be feasible. The project was fully funded by the American Recovery and Reinvestment Act "Green Project Reserve" adminstered by the Oklahoma Water Resources Board.
The first step was to remove the old terrazzo and install a new waterproof membrane to correct leakage problems. The next step was to add insulation and a root-stop barrier. The bottom white later is styrofoam insulation, which was also helped to raise the bed.
Next, a moisture retention layer was added. This was critical due to the long, hot, dry summer in Tulsa as well as the garden's location on a southern exposure. Roof top gardens often also have moisture loss from constant winds. Rather than using soil, LiteTop(r) growing media was utilized to help minimize weight.
Plants were chosen to minimize the need for irrigation and maintenance. A drip irrigation system was installed to assure plant survival while minimizing water consumption. The landscaping design was developed specifically to deter misuse or vandalism of the beds. The final installation is an attractive as well as educational addition to the library. Along with overall beautification, the library has seen a decrease in the amount of abuse and litter in the surrounding plaza.
