- Scrape out and replace any crumbling caulk in joints between siding and trim.
- Sink any visible nails with a nail set. Coat the nail heads with primer, fill the holes with exterior putty, and sand flat.
- Remove loose paint. Scrape off all loose, cracked, alligatored, and peeling paint. Soften stubborn spots with a heat gun (but never use a propane torch!). If paint won’t come off, it has probably bonded to the wood; you can safely paint over it.
- Sand smooth. Sand down the edges around all scraped areas so that the difference between areas with and without old paint won’t show through the new coat. Start with extra-coarse sandpaper, then switch to medium.
- Prime raw areas. Prime all scraped wood, caulk, or putty. If you notice issues with your existing paint job, be sure to troubleshoot first, then fix the problem before painting over it.