Indoor short span natatoria house short course pools and have a narrow width, around 100 feet. Such a space can accommodate all types of pools as long as their widths are in the range listed above. A short span across the building offers greater variety of materials in the relative cost range. Concrete is considered a first choice for life cycle costs due to its total resistance to corrosion and its lifetime durability if properly engineered, constructed and coated. A concrete roof system can be cast-in-place with beams and deck, it can be built up with precast T’s and precast planks or it can be a combination depending on the structural type of the building.
When the natatorium width exceeds100 feet, the depth of the beam and its length begins to add significant costs for both fabrication and for delivery. At these costs, alternative roof structural systems become attractive. The most economical systems are steel trusses, which must be covered with a high-build epoxy coating to protect against corrosion. Glulam beams with wood decking have been successful when the wood is properly processed and humidity in the natatorium is controlled. Tensile roofs are successful in some building types if budget is available for first cost and environment control. If a steel system is chosen, the trusses should be pipe or box-type. Bar and angle joists are difficult to coat and recoat due to recesses and the high number of welds, bolts and webs. Corrosion may occur in these poorly or non-coated points.