I will probably use a similar product
Extruded physical cross-linked extruded polyethylene Density: 30/33 Kg / mc Color: anthracite gray Thicknesses available: from 2 to 12 mm Material description: Closed cell polyethylene foam. Extruded lattice. Excellent physical properties in the static and dynamic field, elasticity, thermal deformability, shock absorption. Thermal insulation, minimum water absorption, low water vapor permeability, resistance to water atmospheric agents, non-polluting, behavior inert chemical. Applications: boating, sporting goods, packaging, camping, construction industry, automotive, healthcare, lighting.