Duties include handling roofs and exterior walls, including felting, sheeting, slates and tiles, to create a waterproof surface, measuring roofs or exterior walls to calculate the necessary amounts of underfelt, tiles, slates, cutting wooden battens; performing lead work, felt, and underfelt to the required size, laying and securing underfelt with adhesive compound, laying, aligning, and securing successive overlapping layers of roofing material, sealing roof edges with mortar to ensure watertight joints, mixing and applying mortar, laying bricks and concrete blocks.