The Rive House will have a floating tread staircase with 29 stairs in total. Building codes require that a ball of 4 inches in diameter cannot pass through any opening in a stairway. With a step-to-step height of 7 inches that means that the tread thickness must be greater than 3 inches. A solid wood slab of this size and 42 inches in length would be prohibitively expensive. Off-the-shelf engineered treads in any decent species of wood run between $300-$400 per tread. I have decided to build our treads from bamboo plywood and constructed the quarter-length prototype pictured above to work out all the construction and assembly details. I really like the result and Jeanine gave her thumbs up as well. The bamboo cost will be $100 per tread so we will enjoy considerable savings as well.