Further product information Our window sills are 4-4.5 cm thick as standard and can be manufactured with straight edges all around or with three straight edges and a simple or rustic tree edge on the front. Surface treatment The natural edge is brushed and lightly sanded to preserve its natural character. We seal larger knotholes, natural cracks, and unevenness with a very dark, black epoxy resin. Smaller knotholes, cracks, and dried-out wormholes are treated with wax on the surface. For...