Caulk hairline cracks on the surface and around windows, doors and other trim with paintable silicone caulking. The Paint Quality Institute warns that power-washing before sealing cracks forces water under the siding, which can cause paint adhesion problems and interior rot and mold.
Clean the synthetic stucco siding with a power washer, using a 45-degree (white) tip. Narrower chiseling tips may damage synthetic stucco, which is softer than wood or traditional concrete stucco. If it is not heavily soiled, a garden hose with a spray nozzle attachment will work just fine. Allow the siding to dry for at least two days.
Repair damaged areas with synthetic stucco patching material, available at most home improvement stores. Apply the patching material to match the existing texture, and allow it to dry for at least eight hours.
Apply one coat of 100 percent acrylic primer with brush and roller or an airless sprayer.
Apply two uniform coats of 100 percent acrylic (water-based) paint, allowing at least eight hours of drying time between coats. Two coats of paint will last longer and look better than one thickly applied coat.