55-inch spiral staircases offer the comfort of a wider tread depth without requiring the larger floor opening of an IRC-compliant spiral. A 55" spiral stair requires a 57" x 57" minimum ceiling opening and is a strong middle-ground option for lofts, basements, decks, and second-floor access in moderately sized spaces. At this diameter, a spiral stair is not IRC compliant for primary egress, so 55" kits remain best suited for secondary access and where local code permits.

We offer 55" spiral stair kits in three product lines: the Manhattan (indoor, all-painted steel construction), the Denver (indoor, solid beech wood treads with powder-coated steel), and the Naples Exterior (outdoor, hot-dip galvanized steel rated for all weather). Each is Italian-designed, ships ready for DIY installation, and offers adjustable rise and a universal landing. Browse the available 55" options below, or see our complete spiral staircase buyer's guide for help choosing between indoor steel, indoor wood, and outdoor configurations.