Westlake Royal Citadel Plus is a polymer modified bituminous sheet material intended for use as underlayment. Underlayment is manufactured as a fiberglass mat surface impregnated and coated with modified bitumen, with a self-adhesive underside and a polymeric surface. Underlayment rolls have approximate dimensions of 72ft x 3ft. Underlayment is self-adhered.
Product has met specification requirements of ASTM D1970.