Chestershield Underslating Felt is a traditionally manufactured, hessian-backed felt for use under tiles or slates. Its fibre base is fully impregnated with a penetration grade bitumen in a saturation bath prior to being jointed with a jute hessian in the coating section.
Coating bitumen is then applied, laminating the hessian to the underside of the saturated base and covering both the top and bottom surfaces. The resulting felt is lightly sanded both sides to prevent sticking.