If you’re happy with the overall look of what you’ve got, then interlocking asphalt roof shingles are definitely worth considering. They work fabulously well as inexpensive, attractive, long-lasting exterior wall siding. They’re also simple to install and nail down easily over the material you’ve got now. I’ve installed them on three buildings. My first installation is 21 years old and shows no sign of deterioration. Regular roof shingles work well as wall siding too, but you’ll need to glue down their lower edges after installation with tar, to stop them from flapping in the wind. Interlocking shingles connect together mechanically, and their more visually intricate joints look nicer on walls. They’re rarely stocked by building supply dealers, but they can be ordered.
What kind of inexpensive exterior wall siding can I install on top of the painted roll roofing that’s above the two doors of my garage? What’s there now has lasted two decades, but needs replacing.