DURASHELL construction involves a process of pressure molding and thermally fusing fiberglass layers to a precision shaped EPS foam core by using a unique foaming epoxy that expands in multiple directions creating a solid, highly durable outer shell. Added between the multiple fiberglass layers is a special combination mat glass reinforcing material to give the board extra strength and durability (kind of like a grid of rebar set within a cement slab). DURASHELL construction gives the customer the best balance of performance, weight, durability, and price.