Almost all materials and finishes used on the outside of a building will last longer if they are regularly cleaned. Cleaning removes dust, dirt, mould, mosses and salt spray - all of which can hasten deterioration.
Cleaning should be carried out with a low-pressure hose and a soft brush. (Water-blasting or harsh brushing might damage the finish or cladding or force water into the wall assembly, and some chemicals can also break down exterior coatings.)
Wash down the exterior of the building yearly. Increase cleaning frequency to 3-monthly in geothermal or severe marine areas.
Where unpainted steel cladding is used, wash down areas not rain-washed at 6-monthly intervals.
Clean glass every 3–4 months, more frequently in severe marine areas.
Regular maintenance of a building exterior will ensure that cladding materials and finishes will have the best chance of performing throughout their relative lifespan and that any potential faults in the exterior are identified – and hopefully dealt with – before they result in a weathertightness failure.
Updated: 19 November 2015