The wonderful thing about designing a stair is the opportunity it presents for playfulness. Unfortunately, this potential is rarely realized. Too often, code and budget restrictions, along with complicated structural considerations, take the fun out of the design.

That was not the case with this Fire Island, N.Y., project. When Jerry Caldari, of New York City based Bromley Caldari Architects, PC, designed the summer house, he didn't skimp on space. The double-height living area boasts a soaring ceiling framed by steel trusses and a custom-built 20-foot folding door that opens to the sea. Such a dramatic room, Caldari decided, deserved a stair that could hold its own, both literally and visually.

Thus, he conceived a steel-framed, semidetached structure that swoops between floors on stringers made of welded steel plates sculpted into whimsical shapes. Most stairs made of steel are commercial stairways; the added dead load of concrete poured into the steel pans for treads makes them heavy, stodgy affairs. This stair, though, combines relatively lightweight oak treads with a beefier stringer design than is commonly found on the commercial versions; it is both very light and very strong. Also, the inside stringer is bolted to a steel angle within the wall; the steel angle is bolted to the wall studs.

To incorporate the code-required intermediate landing, Caldari widened the stringers halfway up. And, in a bit of inspired whimsy, he kerfed the top of the stringer below the landing and the bottom of the stringer above the landing to represent the positions of the treads and risers. The railings are made of simple flat steel bars; the two undulating intermediate members and the curved handrail are welded to straight verticals. Master Rail, of East Quogue, N.Y., fabricated the ironwork.

Caldari's stair is sturdy, inventive, and code-approved. New York state has one of the least restrictive codes in the country in terms of stair construction, and Caldari's design reflects that. In many other areas of the country, though, the codes dictating spacing and height for balusters, risers, and railings are much more restrictive. In these regions--and in any household with children--an open, minimalist design like Caldari's would need to be modified to satisfy safety requirements.