Is it necessary to clean your walls before painting?

When I’m asked to make estimates for interior painting contracts, this is a question which I often hear. Well, it all depends on the surface you want to paint.

Washing the surfaces for interior painting

For interior painting, most of the time, cleaning is not really necessary to paint walls or ceilings. However, for really dirty walls, or for walls with greasy stains or cigarette smoke residues, it’s better to clean thoroughly the walls in order to avoid problems of stains reappearing through the second coat. One could also choose to apply a paint which has stain blocking technology as we now see them on the market, but we still recommend to always cleans your walls first.

Washing exterior surfaces

For exterior painting, a pressure washing is often necessary. This process allows eliminating the mold, damages caused by pollution, streaks left by acid rains, rust particles in suspension, spider webs, chalk, and much more. Note: pressure washing, just like spray gun painting, is not a hazard for cars and neighbor buildings if it’s done by an experienced professional.

Pressure washing: what is it?

Pressure washing is performed with a specially conceived pressure washer. There are a variety of models available on the market with different capacities in terms of pressure. Ideally, go for a pressure washer which allows you to adjust the desired pressure: you should use a lower pressure for a wooden surface and a higher one for a metal surface, for example.

Depending on the problem, it’s sometimes recommended to use hot water, or even vapor (boiling water) to properly clean the dirty surface. In some cases, we will add to the water a soap or industrial degreaser. At FinDecor’s, we prefer eco-friendly and biodegradable solutions when possible. Please note that the use of chemical cleaners is not always necessary.

Finally, washing thoroughly the walls maximizes the paint adhesion of a paint on a given surface: we often recommend it before starting to paint a building. However, this is not always mandatory. We should always ask an expert’s advice to make sure.

Call us now for a free estimate.

Dave Beaupre Master-painter and estimator