An apparatus for working a wet coating on a surface and a method of the same

An apparatus for working a wet coating, such as render material, applied to a surface, comprises an actuator 70, 75 arranged to move an arm 60, 65 across a surface having a wet coating applied thereon; a controller configured to move the arm 60, 65 across the surface along a tool path; and a tool head 80 mounted to the arm 60, 65, the tool head 80 comprising a compliance module 105 and a tool mounted to the compliance module 105 such that the tool is movable in a stroke direction (135 fig. 3) towards the surface relative to the arm 60, 65. The compliance module 105 comprises a biasing module such as a spring 180 arranged to urge the tool in the stroke direction (135 fig. 3) to maintain contact between the tool and the wet coating such that the tool works the wet coating as the arm 60, 65 moves across the surface. The controller may adjust the tool path based on a sensed parameter such as the displacement of the tool relative to the tool head 80 in the stroke direction (135 fig. 3) or a force applied by the actuator 70, 75. The tool may comprise a trowel or a scraper (145 fig. 6). The apparatus may compriose a gantry 50 comprising a frame 55.