Is there a simple way of dealing with powdery surfaces on outside paintwork?

Powdery or chalky old paintwork is caused by the paint film wearing away due to exposure to weather. This natural erosion of the paint coating can often be removed by thoroughly washing down prior to repainting. If washing doesn't remove a chalky surface, seal with the appropriate Weathershield Stabilising Primer before painting, or in severe cases remove the chalky surface entirely.