Apparatus (1200, 1300, 1400, 1600, 1800, 2100) for spraying an insulation material on a surface of a void, the apparatus (1200, 1300, 1400, 1600, 1800, 2100) comprising: at least one elongate member (1202, 1302, 1408, 1602, 1801, 2101) having a distal end and a proximal end, and defining a longitudinal axis; at least one spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) rotatably and mechanically mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801,2101) for spraying the insulation material in a spray pattern, wherein the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) is configured to be mounted at an angle relative to a ground surface, and wherein rotation of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) about the longitudinal axis sweeps a path of the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) through an arc; a ground-engaging member (1218, 1318, 1420, 1618, 1804, 2103) mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) and arranged to facilitate translational movement of the apparatus (1200, 1300, 1400, 1600, 1800, 2100) over a ground surface of the void in response to pushing the elongate member (1202, 1302, 1408, 1602, 1801, 2101) in a direction of the longitudinal axis and in response to pulling the elongate member (1202, 1302, 1408, 1602, 1801, 2101) in a direction of the longitudinal axis; a camera (1206, 1306, 1406, 1606, 1803, 2105) mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) and connected to a camera output, the camera being arranged for capturing images of the spray pattern and the camera output being arranged to facilitate the viewing of captured images of the spray pattern from the proximal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101); and a control mechanism arranged to control the operation of the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) from the proximal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101). at least one elongate member (1202, 1302, 1408, 1602, 1801, 2101) having a distal end and a proximal end, and defining a longitudinal axis; at least one spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) rotatably and mechanically mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801,2101) for spraying the insulation material in a spray pattern, wherein the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) is configured to be mounted at an angle relative to a ground surface, and wherein rotation of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) about the longitudinal axis sweeps a path of the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) through an arc; a ground-engaging member (1218, 1318, 1420, 1618, 1804, 2103) mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) and arranged to facilitate translational movement of the apparatus (1200, 1300, 1400, 1600, 1800, 2100) over a ground surface of the void in response to pushing the elongate member (1202, 1302, 1408, 1602, 1801, 2101) in a direction of the longitudinal axis and in response to pulling the elongate member (1202, 1302, 1408, 1602, 1801, 2101) in a direction of the longitudinal axis; a camera (1206, 1306, 1406, 1606, 1803, 2105) mounted at the distal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101) and connected to a camera output, the camera being arranged for capturing images of the spray pattern and the camera output being arranged to facilitate the viewing of captured images of the spray pattern from the proximal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101); and a control mechanism arranged to control the operation of the spray nozzle (1204, 1302, 1404, 1604, 1805, 2102) from the proximal end of the elongate member (1202, 1302, 1408, 1602, 1801, 2101).