Same as Low Density Expanded Polystyrene, except:
Common name: High density Bead Board
Thermal Resistance: RSI - .028/mm R - 4.0/in. High.
-- It is less fragile than the low density bead board and can take higher compression pressures.
-- Inside foundation walls, outside upper wall framing under siding, roofs.
-- It has proven reliable in underground applications for external foundation insulation where the low density board is not recommended for this.
-- Under concrete slabs, extruded polystyrene is a product better able to take the long term pressure.