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A floating pool for Paris
An Olympic-length swimming pool, therapy baths, and a rooftop running track are floating on the Seine inside a sleek, steel-structured barge named Annette K. Designed for public use year-round, it’s a bold return to river life, made possible by the quiet strength of molybdenum-containing stainless steel.
© Sergio Grazia / Seine Design
In the heart of Paris, something remarkable has taken shape on the water. Launched through “Reinventing the Seine”, a city initiative to bring new life to the river, Annette K. is part of a broader ambition. The goal is to reconnect Parisians with the Seine, not only visually but also physically as a place to swim, move, and gather. In design, spirit, and material performance, Annette K. marks a new chapter in Paris’ relationship with the water that shaped it.
Stainless strength and smart space
The centerpiece of Annette K. is a fully structural pool made from Type 316L stainless steel, an alloy containing about 2% molybdenum. This composition provides exceptional resistance to pitting and crevice corrosion in chloride-rich environments, like chlorinated pool water. The alloy was selected not only for its durability, but because it allowed for a thin, efficient structure that maximized usable space inside the floating building.
Thin steel walls mean more room for people and amenities, like lockers, therapy rooms, or technical systems, without expanding the barge’s footprint. The pool shell and supporting framework double as both a water container and an architectural skeleton, eliminating the need for suspended ceilings or raised floors.
Unlike concrete, which requires thick walls, tiles, or protective coatings, Type 316L stainless steel elements can be prefabricated and then welded together on site to form the pool shell. The remarkably thin 3mm embossed floor and 4mm smooth wall panels create a lightweight, watertight structure. The pool won’t leak, crack, or degrade. Its non-porous surface is easy to clean and naturally resists the buildup of algae and bacteria.
Services run through the exposed ducts and steel framework with the clarity of a shipbuilder’s plan. The spider-like structural legs support walls and panels while guiding an organized network of utilities through the building, including the pool’s inflow and outflow piping, which are also made of Type 316L stainless steel to ensure long-term corrosion resistance.
Discover more about the Annette K. here.
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