Seats and backs . The seats and backs of Bertolini chairs are made of marine birch plywood. This type of plywood holds up especially well in Hawaii or the coastal Southeast, where humidity is a problem. North American Seating uses polymer resin boards that last longer than plywood. How wood and frame meet is a defining point in the strength of a chair.
Bertolini chairs have a rivet on one side and a bolt that passes through the frame into the rivet.
Other manufacturers use special screws to secure the connections. Padding plus . Polyurethane foam, used to pad chair seats and backs, is measured by density and softness. Over time, the padding in any chair will compress and the chair may not feel as comfortable. But if you feel the wood in a chair soon after purchasing it, the quality of its foam may be suspect.