How to Prep a Surface for Exterior Paint

Clean the surface. Dirty surfaces lead to spotty coverage and chipping later on. For exterior siding, use a pressure washer to get rid of dirt and grime. Furniture is best cleaned with a sponge and trisodium phosphate cleanser. Outdoor masonry should be washed with a muriatic acid cleanser and a rag.

Sand slick surfaces with 220-grit sandpaper. An existing glossy finish needs to be roughed up for better paint adhesion. Masonry obviously does not require sanding, but slick vinyl siding or varnished furniture needs some abrasion before you paint.

Protect fixtures and hardware with painter's tape, and protect large surfaces with plastic sheeting.

Apply primer to surfaces before painting. Priming is perhaps the most important exterior preparation. Painting over primer leads to longer-lasting, more professional-looking results when compared to painting over raw surfaces. General-purpose exterior primer is useful in most cases. For rigid masonry, elastomeric primer is best. Very slick, nonporous siding requires bonding primer.