One of the burdens and hassles of living in an RV is the issue of water. Water inside and water outside, and preventing water outside from coming inside.
RVers Corner shows off a device for testing leaks from the inside out. They use a new machine that pressurizes the inside of the RV and fills it with air like a balloon. By spraying soapy water on the outside of the trailer or motor home, you can see where the bubbles are is where air is pushing out through leaks.
The closeup pictures are amazing. Some of the leaks around the doors are typical, but some along the molding and other areas are not. And they are prime leak spot for water to get in from the outside.
The process is better described by Phrannie, RV Repair Specialist:
Don’t start taking things apart until you know where the water leaks are coming from!
To do this effectively, you need to “overpressurize” the interior of the RV. It’s simple, but can take some time. You will seek to have more air pressure inside, than outside. Simply tape up vacant “holes, cracks or other openings” and/or stuff them with what’s at hand. Then, run a line from an air compressor or (vacuum cleaner backside) into the RV. It’s not critical that everything be totally “tight.”
A more efficient (quicker) way to do the above leak check is to rent one of the fans used to inflate portable structures. It has a BIG fan and feeds the air through a very large flexible hose. You can stick the hose end in a window and plug the excess space with tape, cardboard, rags, etc., as above.
Before doing the leak check, you’ll need to open some of the inner ceiling so the air can pressurize the roof. Easier way is to remove trim from ceiling vents and (gently) pry inner ceiling loose and insert wedges, pencils, whatever to keep it open.
Once the air pressure on the inside is more than the air pressure on the outside, you go around the whole RV (sometimes on a ladder) and spray a windex-type bottle, with a mix of detergent and water, on any possible “leaker” place (like you would when looking for an LP gas leak). Seams, joints, whatever. If bubbles appear, that’s where air is leaking out — and that’s also where water is leaking IN. (This is basic high-school physics.) Mark these places.
Your next job is to fix those leaks! If you don’t do this first, and if you don’t do it properly, leaks (and more dry rot) will keep coming back to haunt you in the future.
If you are experiencing water damage and can’t track down the cause, this is an ideal method to get to the root of your leaks, and prevent more future water damage from leaks you didn’t even know you had.