Before you buy, the roof deserves a very careful inspection because even a small leak can turn into rotten wood, mold, soft walls, and repairs that cost far more than the RV is worth. Start with a visual check from the ground, then get up there if it is safe and allowed. You want to look for cracks, splits, soft spots, bubbles, seams pulling apart, patched areas, and any signs that the roof material is drying out or curling. Pay special attention to places where the roof meets vents, skylights, antennas, air conditioners, ladder mounts, and corner edges. Those are common leak points.
If the roof is a rubber membrane, press gently with your hand to see whether it feels firm or spongy. A soft spot can mean water has gotten into the plywood underneath. On a fiberglass or metal roof, look for dents, lifted seams, missing sealant, or corrosion around fasteners. Sealant is supposed to protect joints, but if it is cracked, peeling, or shrunk away from the edge, that usually means maintenance has been neglected. A roof that has obviously been resealed many times is not automatically a deal breaker, but it does mean you should ask why.
Inside the RV, check the ceiling and upper corners for stains, discoloration, sagging panels, or a musty smell. A roof can look decent outside and still have hidden damage inside. Open cabinets near the ceiling and look for dark spots, warped wood, or peeling wallpaper. If there is an enclosed attic space or hidden cavity, use a flashlight and inspect as much as you can. Bring a flashlight and, if possible, a small ladder or step stool so you can get a better view without guessing from the ground.
If the seller allows it, use a moisture meter on suspect areas. It will not tell the whole story, but it can help you spot areas that have absorbed water. Also ask for maintenance records. A roof that was cleaned and resealed on schedule is usually a better bet than one with no history at all. If the RV has been sitting outside for years, especially in hot sun or heavy rain, be more cautious.
One last thing: if you are not confident, hire a qualified RV inspector. Paying for a professional inspection is often cheaper than finding out after purchase that the roof needs major repair. A little time spent checking the roof thoroughly can save you a lot of regret later.
