Remove any loose paint pieces by scrubbing the wall with a wire brush.
Hose the wall down with a garden hose to remove dirt and any remaining loose paint pieces, then allow the wall to dry.
Apply a single coat of acrylic-latex masonry primer to the wall with a roller brush and allow the wall to dry. Use a roller brush with a wide nap to substantially reduce the application time.
Apply a layer of acrylic-latex paint in the chosen color to the wall with the roller brush.
Wipe down the surface of the wall with clean water and a sponge, then allow the wall to dry. The goal here is to remove any heavy deposits that might gouge the wood during the sanding process.
Sand the surface of the wall lightly with fine-grit sandpaper to remove any loose paint pieces.
Wipe down the wall a second time to remove the debris left by the sanding process.
Apply fast-drying oil based primer or latex primer only to any areas of exposed wood with a paint brush.
Apply a coat of exterior house paint to the wall. Use a roller brush if the wall is flat. Apply the paint with a paint brush or with paint pads if the wall has a staggered surface.
Spray the wall down with a pressure sprayer. Avoid spraying close to doors and windows to avoid water spraying into the home. Clean the areas surrounding doors and windows with a stiff-bristled brush.
Apply a coat of acrylic-latex stain-blocking primer to the wall with a paint brush. Apply the paint horizontally rather than vertically, starting at the top of the wall and moving downward. Note that this type of paint is available for either vinyl or aluminum siding. Check the paint label to ensure that you are purchasing the paint designed for your surface.
Apply the paint of the chosen color to the siding with a paint brush. Do not apply paint that is darker that the original paint color, which can attract heat and potentially warp the siding.