General Surface Preparation

Loosely Bound and Peeling Paint

Remove as much loose and peeling paint by scraping, wire brushing or power-washing the surface. Feather sand rough edges smooth until they blend with bare surface.

Dirt, Grease, Oil, Chalky Surfaces

Remove these deposits by washing with a detergent solution using a sponge or brush. Protected areas need special attention to remove invisible deposits that can promote a premature peeling problem. After washing, thoroughly rinse with clean water and allow it to dry. Power washing is also a fast, effective method of removing dirt, chalky deposits.

Mildew

Spotty patches that look like dirt, but do not come off when scrubbed with detergent solution are probably mildew. Mildew can occur on any side of the house, but is more likely to grow in shaded areas or behind shrubbery. It can easily be identified from other forms of discoloration by applying a few drops of bleach. If mildew is present, the black, gray or brown color will bleach out and disappear within one or two minutes. Mildew must be killed and removed before repainting. If the mildew is not completely removed, the active spores will continue to grow and may almost immediately begin to reappear on a recently repainted surface. Where mildew is present, apply a solution of one part household bleach and three parts water.

Rust

Remove all rust by sandblasting, wire brush, steel wool or sandpaper. See Iron, Steel and Ferrous Metal section for SSPC preparation methods.

Cracks, Splits and Open Joints

Cracks and/or open joints, where water may enter should be sealed with a high-quality paintable sealer. Apply primer over sealed area.

Glossy Surfaces

Always rub down surfaces with sandpaper.

Rusty/Loose Nails

Replace loose nails with slightly larger, galvanized nails. Leave nail heads flush with hardboard surfaces and counter sink on all other wood surfaces. Prime with a corrosion resistant primer.

Wax Migration

This condition can be encountered on hardboard surfaces. If a stain or discoloration persists after removing dirt and/or mildew, it may be a wax migration from the siding. It can be identified by applying a few drops of water, both to a discolored area and an adjacent non discolored area. If the water beads on the discolored area, but spreads or is absorbed in the areas around the stain, a wax migration condition probably exists in the stained area. In most cases this discoloration can be removed with a hot detergent solution, followed with a thorough rinsing with clean water. In extreme cases removing the stain by wiping the area with a clean rag, wet with mineral spirits, may be necessary, followed by a detergent solution wash and clean-water rinse. Repeating either process may be necessary until clear water ceases to bead up on the affected area. Prime the affected area prior to top coating.

Previously Coated Surfaces

It is not always possible to remove all old coating for repainting works. Understand that any surface preparation, short of complete removal of all old coatings, may compromise the service life of the new coating system. Check compatibility of previously painted surfaces using a test patch with the coating if there is any doubt on recoatability.