The Steel Sub-Structure used in MAAX Spas® units has the highest strength to weight ratio of any building material available. The light-gauge steel frame provides greater structural integrity than wood, as well as superior corrosion protection for a much longer life. Unlike wood, steel is dimensionally stable. It will not expand or contract with moisture, which over time can damage the spa’s exterior. Sturdy and built to last longer, the inorganic properties will never rot, warp, split or crack and eliminate worries of animal infestation or termite damage. Stronger, more durable, and ideal for the environment – it’s the obvious choice for a lifetime of worry-free fun.