Aluminium rainwater systems are becoming increasingly popular, and cater for all types of domestic, commercial and industrial building, either of traditional or modern design. Plain finish products are available, but much more in vogue are the polyester paint powder-coated finishes that are available and which can complement or contrast with brickwork, windows and roofing as required. The durability of both painted and unpainted aluminium rainwater goods is excellent. The benefits of pre-painted aluminium alloy coil are put to good use by manufacturers offering on-site guttermaking and fixing. A liberal coating of bitumen is recommended as an insulant between, for example, lead flashings in contact with aluminium gutterwork, and between downpipes and any touching cement or brickwork. The advent of powder-coating techniques and of pre-coated aluminium coil has added a colourful new dimension and led to a significant growth in demand.