1. Before painting an exterior wall, brush it down well to remove any loose material start at the top and use a fairly stiff brush.

2. Kill mould and algae with a solution of 1 part bleach to 4 parts water. Leave for two days, then wash down and brush off.

3. Rusty metal and leaky gutters can easily cause stains, so cure the leaks and clean and prime al metal first. Sterilize the stain and brush down.

4. Holes in the wall are often created when old down pipe brackets are removed. Brush them out well and damp the surface with a little water.

5. Fill the hole with a sand and cement mixture using a small trowel. Small bags of ready-mixed mortar are ideal for jobs of this size.

6. If the wall is powdery or highly porous, or if a cement-based paint has been used previously, seal the surface with a stabilizing primer.