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DIY leak pressure test

rlw999
Explorer
Explorer
I've found that I had a small leak in my RV roof at the end of the season last year but couldn't find the source. I kept it covered during the rainy winter (along with a dehumidifier) and figured that I'd take it to a shop for a pressure test after the rain ended. I called around to a few places nearby and they are booked up for 6 - 8 weeks.

So I did it myself. I started with this post and this website

I'd heard about people using leafblowers, but some also said that they couldn't get enough pressure. So instead, I used a 1 hp "bouncy house" inflator - those blowers are rated to produce up to 9" water column pressure, so I knew it had the ability to pressurize, as long as I could seal up enough leaks.

I cut up some foam art boards to fit over a window, and cut a hole for a 6" HVAC hose. Then used a foam board to fit that 6" hose over the suction side of the bouncy house blower. Whatever that blower body is made out of, tape doesn't stuck to it, fortunately there's enough suction to hold the foam board in place during operation.

I used some 1/2" tubing to make a water column pressure gauge to make sure I didn't over inflate. Turns out that wasn't a problem.

I taped over every air outlet I could find - drains, RV dash vents, stove vent, etc.

Powered it on and the pressure gauge didn't move at all, so I walked around the RV and found that even though I had taped over the stove vent from the inside, the vent housing must have had other gaps as I could feel strong airflow coming out of the outside vent, so I taped it over from the outside. My roof vents were also leaking considerable air, they aren't really made to keep pressurized air in, so I put a couple water bottles on each one to hold it closed. Also I could feel air escaping around the RV door so I taped that up from the outside as well.

Finally the water in the pressure gauge moved about 1/16" of an inch. I wasn't sure that'd be enough, but I figured I'd give it a try. I went up on the roof and sprayed every seal with soapy water and sure enough, I saw big bubbles coming out around the dicor that seals the antenna, I lifted it up with my fingernail, and the roof membrane was cracked there.

I sprayed all of the windows and other penetrations on the sides, and I also found bubbles coming up around the door frame.



I ended up covering the leak on top of the roof with a piece of eternabond tape, then Dicor lapsealent on top of that whole penetration. I ordered some Dicor non-sag sealant that I'll use for the door frame (I'm sure a better fix would be to pull the doorframe and put in new butyl tape, but that's more than I want to tackle myself)

Here's the blower:



And the roof leak:



And the door leak:





And here's a link to the 1HP bouncy house blower I used.

My total cost for this was $160 to get the blower (though looks like the price increased to $180 now), since I already had everything else. I'd have paid $350 - $400 for the test at a dealer.
6 REPLIES 6

billyboy
Explorer
Explorer
Last week I. Bought a 1520 cfm blower from overstock .com for 70.00 and mount4d it in my kitchen window. It seems to have enough pressure after sealing floor vents etc.it looks to be leaking where the fiberglass roof sits in the aluminum trim, that Winnebago uses and its so cheesy and stupid for a winny.
09 winny adventurer 32h 33 ft towing 015 focus

Durb
Explorer
Explorer
Informative post. A visual inspection most likely would have not picked up those leak points.

DrewE
Explorer II
Explorer II
I've read (here, I think) that a shop vac can also be effective. If I were attempting to do this sort of test in a DIY fashion, that's what I would try first since I already have one.

Gdetrailer
Explorer III
Explorer III
Cool idea, bouncy house fan most likely would be MUCH quieter than any leaf blower..

Hmm, makes me think of the spare huge old furnace fan I have laying around..

gbopp
Explorer
Explorer
Great project, thanks for sharing. :C

Grit_dog
Nomad III
Nomad III
Nice work!
Thanks for sharing.
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