Walkable roof decks are limited to the use of membrane covered roofs except where a roof planking system is specifically designed to support this by other means, specific to the particular plank system. Using any of the flat membrane roof approaches accommodation for decking is first accomplished by adding extensions to the perimeter Primary corner posts through the roof membrane and though a plastic end cover cap sealed around the base of the extension post with silicone sealant. Edges of the corner post extension profile must be rounded smooth to help prevent cuts in the roof membrane. These extension corner posts then serve as the foundation for a standard deck grid like that of the standard perimeter deck but using only 50mm high profiles. The floor grid is raised from the membrane surface by modified plastic end-caps, door stops, or round alloy baseplates placed at cross-points in the frame grid. (these have no attachment to the roof surface, only resting on top) The same decking used in the standard perimeter deck system is then installed along with any hand rails supported by corner extension posts and base perimeter beams.
Alternatively, the corner extensions can be used just to support just hand rails and a perimeter tie beam that locks continuous roof deck aluminum or polywood profile planks, as made by a number of manufacturers. These interlocking planks work much like floating hardwood ‘snap’ floor planking and are designed to drain rainwater chiefly in one direction. This is also used as an option in perimeter decking.
Prefabricated wood or polywood deck tiles can also be employed with this same perimeter tie beam serving mostly as a perimeter frame.
Note that decking and hand rails should not extend beyond the perimeter of the Primary structural frame of a Utilihab structure. Cantilevered roof overhangs do not support walkable decking, but may incorporate lighter features such as Green Wall based green roof panels.