Guest Column - September 2014
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Design Corner

Making a Splash
Adaptive Use of Older Structures Suited to Small Natatoriums

By David Petta and Diana Hayton

Accommodating a pool within such a structure means removing the slab, since pools require decks with exacting tolerances of one-quarter inch of slope and, if the concrete will be the finished surface, a brushed surface to mitigate the risk of slip falls. (Auto garages, by contrast, feature flat, smooth concrete.) Even this is a simple operation, since the slab itself isn't structural. Earthworks, laying pool piping, creation of a pool shell—these follow the normal procedures for any other pool.

Ancillary spaces can be a bit trickier to accommodate within an existing building shell just because the quality of the space will vary and space will sometimes be limited. Splash's pool is a 60-by-36-foot rectangle notched by seven water benches and an entry stair, surrounded by a narrow deck. Behind glass at one end, parent viewing (three rows of chairs) gives way to girls' and boys' toilet rooms; a family changing room with seven private cubicles; a unisex toilet and a pool deck shower; and the entry lobby, check-in desk and one small administrators' office. Storage and pool equipment occupy small rooms added to the west exterior, a demonstration of the 6,500-square-foot building's tight plan.

Much of an adaptive reuse involves deciding what to keep—and embellish. Splash kept one operable garage door in place next to the pool entry (it helps hold the garage aesthetic and allows large objects to be brought in or out), filled the lobby bay with a glass entry door and storefront glass, and filled the rest with concrete block. The previous use was strictly utilitarian, so certain accoutrements, such as operable sun shades, needed to be added for the comfort of kids and their parents and caretakers.

The most difficult aspect of natatorium construction, here and elsewhere, is the design of mechanical systems. The pool area is kept at 91 degrees for the comfort of swimmers, while the glassed-in dry portion is conditioned to around 70. The air-circulation system ensures that there are no dead zones within either space and must be aimed to prevent condensation from rusting fixtures and from forming on the glass between the cool and warm zones.

The final price tag on the Splash adaptive reuse was $1 million, with the building's landlord picking up the cost of a new roof and roof insulation. At a time when municipal natatoriums have become more like waterparks and cost their cities hundreds of thousands of dollars to operate, a building project of this scope—with a business plan that is solidly in the black—offers another path toward meeting demand for recreation services. And for the city of Walnut Creek, the refurbishment of an older structure helps meet its longer-term goals for a neighborhood transitioning from light industrial to mixed-use.

David Petta, FAIA, LEED AP BD+C is a principal, and Diana Hayton, AIA, LEED AP BD+C is an associate principal, with ELS Architecture and Urban Design in Berkeley, Calif. For more information, visit