Q. We had an extension built and now have exposed white plastic windows and waste pipes, a brown pipe going into the drain, a grey plastic soil stack, and black plastic gutters and down pipes. Would the life of all this plastic be prolonged if painted, and is there a special paint for the job?
A. All plastics become brittle through exposure to u/v light, but not at the same rate. This will depend upon the type of plastic, the colour, and the amount of u/v stabiliser used in manufacture. Your white internal waste pipes are probably polypropylene, and the windows, brown and grey drainage pipes, and black guttering, are PVC-U.
The biggest maintenance requirement for PVC-U (the ‘U’ stands for ‘unplasticised’) products is to keep them clean. The plastic surfaces seem to attract dust and pollutants – possibly by electrostatic attraction – and white PVC-U can quickly become dirty. So all PVC-U windows and roofline products should be washed with detergent at least once a year – more frequently in towns or areas close to the sea. All plastics will last longer if painted. ICI/Dulux make Weathershield PVC-U paint – for use on weathered PVC-U windows – which will need rubbing down and re-coating every few years, like all paintwork, but ordinary spirit-based undercoat and gloss can also be used.