In this build I’m taking you through the full exterior process of a DIY tiny house on a 20-foot trailer, start to finish. The big takeaway is that the exterior isn’t one “step”—it’s a chain of details that all have to work together: weatherproofing, windows/door layout, siding, stain/paint choices, and a roof system that won’t leak. I built this the same way I build everything on the channel—real tools, real costs, and real results—so you can copy it without guessing. This exterior took me about four weeks, and most of that time is the unglamorous stuff that makes the house last: sealing, flashing, cutting clean openings, and making sure the roof and wall layers shed water the right way. I also cover the specific products and tools that make the job faster (and less frustrating), like metal-cutting attachments, good sealant, ice-and-water barrier, and a siding tool that helps keep your lines consistent. If you’re planning a tiny home on wheels, this video is the roadmap for getting a tight, clean exterior—and part two is where I’ll move inside and start finishing the interior.