Inspecting a Used RV Before You Buy It

Pack light but pack deliberately. A pin type moisture meter, a bright handheld light, a small mirror on a telescoping handle, a plastic tipped tap hammer or a quarter, an awl or a thin screwdriver for probing, a tire tread depth gauge, a non-contact voltage tester, a pair of nitrile gloves and a notepad cover almost everything. Knee pads and a headlamp make the underside survey tolerable. A step ladder matters if the coach has no roof ladder, and never climb onto a roof you have not first confirmed will carry your weight from the edge.

The order is roof, exterior walls and caps, slides, interior, systems, then chassis and paperwork. Each stage feeds the next. A cracked sealant bead at a roof vent tells you exactly which interior ceiling corner to examine with the meter. A stain at the base of the wardrobe tells you which exterior seam to re-examine from outside. Working in this direction means that by the time you are inside, you already have a short list of suspect locations and you are confirming a hypothesis instead of wandering around opening cabinet doors at random.

Give yourself two to three hours and tell the seller that up front. An inspection that gets rushed because somebody has a dinner reservation is the one that misses the soft floor. Ask permission before probing anything with a sharp tool, and probe in concealed locations such as inside a storage bay or under the edge of a step rather than in the middle of a visible panel. Photograph everything you flag, with something in frame for scale, because you will want those images later when you are pricing the work.

Get on the roof only if it feels solid from the ladder. Walk the perimeter first, staying over the rafters near the edges, and pay attention to what your feet report. A slight give between rafters is normal on a thin decked roof. A distinct sponginess, a crunch, or a spot that stays depressed after your weight moves off is a decked substrate that has absorbed water and lost strength. Note where it is, because that location almost always sits directly below or beside a penetration whose sealant let go some time ago.

Then audit every penetration individually. Roof vents, the air conditioner gasket, skylights, refrigerator vents, antennas, solar mounts, the ladder standoffs, and the front and rear cap to roof transitions each get a close look. What you are looking for is not dirt; it is a bead that has shrunk away from one side of the joint, cracked across its shoulder, or hardened to the point that it no longer moves with the panel. Press a fingernail into a suspect bead. Fresh lap sealant yields. Old sealant that has fully cured out is brittle and crazed.

Identify the membrane while you are up there, because it changes the maintenance picture. EPDM rubber chalks white and transfers a residue to your hand. TPO stays whiter and gets brittle rather than chalky. A fiberglass roof shows gelcoat oxidation and sometimes stress cracks radiating from mounting points. Any patch you find made from a material that does not match the membrane, or any place where somebody smeared a general purpose silicone over a self-leveling joint, is a repair done in a hurry and it is worth investigating what it was hiding.

Stand at the front corner and sight down the length of the sidewall with the sun at a low angle to your left or right. Raking light turns a flat wall into a topographic map. Waves, dishing between framing members and a slight bulge with a defined edge all become visible in a way they never are from straight on. A ripple pattern that follows the framing usually means the adhesive bond is releasing. A localized bulge with a hard boundary usually means water has collected between the skin and the lauan facer behind it. Confirm either one with a tap test.

Move to the seams. Front and rear cap to sidewall joints, the belt molding, the window flanges, the entry door frame and every service door flange are all mechanical joints that depend on sealant and screws. Look for screws that have backed out, sealant that has separated on one leg of a joint, and any streaking on the wall below a joint that suggests water has been running there. On a fifth wheel, examine the front cap radius carefully, since that panel takes the most road spray and the most flex.

Run every slide out and back in, with the unit level and on shore power, and listen. A healthy room moves at a steady pace with an even motor tone. A room that stutters, that pauses partway, or that makes the motor labor as it approaches full travel has a mechanism problem, a synchronization problem or an obstruction. Watch the exterior seal as the room comes in and confirm the bulb seal compresses evenly along its entire length. Check the interior floor at the leading edge for staining, which is the classic symptom of a seal that has been leaking quietly.

Inside, take the meter to the same five places every time: the base of every exterior wall, the wardrobe floor, the floor under the bed, the rear corners, and the ceiling directly around each roof penetration. Establish a baseline reading on a wall you are confident is dry, then compare. Smell matters as much as the meter; a musty note that appears when you open a closed cabinet is decayed lauan, and it does not come from anywhere else. Press a thumb firmly into the wall at the floor junction. Sound paneling resists. Compromised paneling gives.

Probe the subfloor where it will not show. Inside a storage bay, at the back edge of the shower pan, beneath the entry step, and along the slide out floor rails are the usual candidates. An awl pressed into sound plywood stops within an eighth of an inch. In delaminated or rotted plywood it sinks with almost no resistance, and that is your answer. Walk the entire floor slowly in stocking feet, especially along the slide rails and the perimeter, and note any location that flexes more than the area around it.

Then load the systems all at once rather than one at a time, because sequential testing hides the problems. Start the refrigerator on shore power and again on propane and let both run long enough to feel a genuine temperature drop, which takes considerably longer than most buyers allow. Light the water heater and the furnace, run the roof air conditioner, run the microwave, and turn on the water pump. Anything that trips a breaker, browns out the lights, or refuses to light under load in that combination is telling you about a real deficiency you would otherwise discover on your first trip.

Get under it with a light. Read the date code stamped after the DOT prefix on every tire, including the spare; the last four digits give the week and the year of manufacture, and rubber ages out on a calendar regardless of tread depth. Look for sidewall crazing and for cracks at the base of the tread blocks. On a leaf sprung trailer, examine the equalizer, the shackle links and the bolts. Original unbushed bolts wear oval and let the axles walk; wet bolt kits with grease fittings are the common upgrade and their presence tells you the owner was attentive.

Keep going. A leaf pack that has flattened or has one leaf sitting proud of its neighbors is sagging and it changes ride height and axle alignment. On torsion axles, check the ride height against the other side and look at the rubber cords through the end cap opening if it is accessible, since torsion rubber compresses permanently and cannot be adjusted back. Spin each wheel with the axle raised and listen for bearing roughness or feel for play at the twelve and six o'clock positions. Look at the generator hour meter, then start it and put a real load on it, because a generator that runs unloaded proves very little.

Now do the arithmetic. Put a labor hour estimate next to each item and multiply by the rate it will be billed at, which here is $210 per hour for body and paint, $260 per hour for mechanical and electrical and $285 per hour for in depth diagnostics. A full sealant refresh is commonly six to ten hours. A slide seal replacement is four to eight. A rear corner subfloor section is twenty to forty. A shop level pre purchase evaluation goes further than an owner walkaround, since a lift, a pressure test and a moisture survey by the systems department produce documentation a seller has to answer to. Systems evaluations are $150, credited against an authorized repair.