How to Prepare Exterior Siding for a Fresh Coat of Paint

Siding represents the first line of defense for your home against the elements, and its condition dictates the longevity of your paint job. Skipping the preparation stage is the fastest way to ensure your new paint peels within two seasons. When done correctly, this process isn't just about cleaning; it's about creating a stable, receptive foundation that locks the new coating to the structure. Taking the time to scrape, patch, and prime is where the real work happens. A fresh coat of paint might hide the surface, but it cannot fix rot or moisture traps hidden beneath old, failing layers. Treat the preparation as the most important part of the job, and the final application will take half the time and last twice as long.

Clear the Wall First. Remove all shutters, light fixtures, and house numbers from the siding. Trim back any bushes or tree branches that are within two feet of the wall to ensure full access.
Blast Away the Grime. Use a pressure washer on a low-pressure setting or a stiff-bristled scrub brush with a mixture of water and mild detergent. Scrub away all mold, mildew, and loose dirt, working from the top down.
Remove Failing Paint. Use a carbide-tipped paint scraper to remove any bubbling, peeling, or flaking paint. Be aggressive enough to reach solid paint, but avoid gouging the wood or siding material.
Feather the Edges Smooth. Use a sanding block or palm sander with 80-grit sandpaper to feather the edges where the old paint meets the bare siding. This creates a smooth transition that won't be visible once painted.
Seal Every Imperfection. Fill any holes, cracks, or deep gouges with a high-quality exterior wood filler or patching compound. Once dry, sand the patched areas until they are perfectly flush with the surrounding surface.
Prime Bare Wood Now. Spot-prime all bare wood or patched areas using a high-quality exterior-grade primer. This seals the surface and ensures the topcoat adheres evenly across the entire wall.