An exterior paint job isn't as simple as slapping on a coat or two of fresh paint. Proper preparation is a must for an attractive and long-lasting finish.

1. Contaminant Removal

Contaminants settle on the paint over time, and they can make it hard for new coats of paint to adhere properly. These contaminants include air pollutants, pollen, bird droppings, and general dust and grime. Washing the siding before doing any other prep work is a must. It's typically done with a pressure washer or a deck brush. A cleaning solution may be used if there is stubborn grime. 

2. Sanding and Smoothing

Old, peeling paint, stains, and other coatings will also prevent the new paint from sticking properly. The peeling and flaking will simply transfer into the new paint and you'll end up with the same problem. Washing will remove some of the flaking paint, but further sanding is often necessary to fully remove it. This also smooths out any rough areas on the siding so that it will be better able to take on the paint.

3. Repairs

Now that the exterior is clean and sanded, it is easier to spot problem areas. Any holes or minor cracks may need to be patched with a wood putty. Rot is a more severe problem, as it results in soft, decomposing wood that can't be fixed. Any rotting bits of the siding will require a full replacement. The trim and eaves should also be checked for rot if they are made of wood and are going to be repainted at the same time as the main home exterior. 

4. Surface Dulling

Overly smooth or shiny areas won't take the new paint well, as it will simply peel off. To adhere, the surface needs to be dull and slightly rough. If you sanded the entire exterior previously to remove flaking paint, then this step is complete. On the other hand, if some areas weren't sanded because there was no flaking to deal with, they will need to be sanded with a fine-grain sandpaper before painting.

5. Priming

Priming bridges the preparation and painting parts of the process. A coat of a quality exterior latex primer will smooth out color inconsistencies so that the paint will provide even coverage with fewer coats. Primer also seals in stains so they don't soak through the new paint, while it also creates a surface to which the final coats of paint will better adhere. 

Contact an exterior painting service for more information on proper painting techniques.