Roof leak around air conditioner

[The_Titan]

I suspect my air conditioner roof gasket is leaking, instead of replacing it I hope to caulk around it. My questions are, what kinds of caulk are compatible with TPO roofs and if I should have to replace the gasket, at a later date, will I be able to clean the caulk off the roof? I have been around long enough to know that patch up repairs rarely are a good idea, but in this case I want to try anyway.

[w8eh]

I had a Jayco that either the AC was installed with loose bolts or the bolts worked loose and caused a major leak. I pulled the AC off and could see where the water left dirt marks on the roof running under the gasket.

After cleaning the roof around the AC, I used the Dicor roof sealant on the bottom side of an new seal, effectively sealing it to the roof. Reinstalled the AC and tightened down the bolts to spec. Then I checked those 4 hold down bolts twice a season to be sure that they didn't work loose.

The AC bolts should be checked on your camper every time that the roof is inspected, which should be at least once a year.

Ernie

[deltabravo]

turbojimmy wrote:
The only way to do it right is to remove the A/C unit, and if you're going to do that you may as well replace the $20 gasket. If you try to caulk around it you'll just make a mess (BTDT).

But if you insist, I'd use an interior/exterior type door & window caulk. I've used it before and it peels off easily - at least off of my old-school aluminum roof.

Ditto.

Chances are good that the screws have worked loose. I've had that problem happen twice on the same rig, so the last time it happened, I put thread lock compound on the screws.

[fly-swatter]

I had the same issue last month, gave the bolts a couple turns and all seems good now

[Mark_and_Linda]

Just got through checking my bolts after a vibration I had from the fan.Three were loose.

Did you find your problem?

[RICK-ards_Red]

My last trailer the air conditioner also leaked, turned out it was not properly fastened to the roof and could have lost it while traveling. I agree with the others, don't caulk it - get it checked out first.

[HuckleberryHunt]

wildtoad wrote:
Do not caulk it, take the time and effort to remove the old and put on the new. The po of one of the used units I bought caulked and it still leaked and caused a real mess. Have you tried just tightening the mounting bolts and compressing the current gasket more?

Agree. Tighten up the bolts and if that fails go through the effort of getting a new gasket.

[RoyB]

I have had my four long screws get vibrated loose especially going down bumpy concrete separation every 8-feet or so.

You can pull the bottom cover on the interior ceiling side and see the gasket in question. It should be depressed about a 1/4-inch all the way around it...

Easy job to re-tighten the four long screws depressing the 14" x 14" gasket.

The only other times I have got water coming through the A/C ceiling vent is when it would ice-up during very humid days/nights... Could be doing this on you as well...

On those very humid nights in our OFF-ROAD POPUP trailer running one of those 11-inch O-2 COOL portable fan's inside the area really helped alot...

Roy Ken

[Toddupton]

Don't do it! It will take less time to replace the gasket that to try and caulk it.

[mike-s]

Dicor self-leveling lap sealant or Eternabond tape. Neither is easily removed completely, but if something more extensive is required at a later date, they can be removed enough to effect a further repair.

[wrgrs50s]

as stated earlier, tighten the bolts on the AC unit. It is a crush type gasket, and may need just a bit more tension to seal. Most likely that will do the trick.

[wildtoad]

Do not caulk it, take the time and effort to remove the old and put on the new. The po of one of the used units I bought caulked and it still leaked and caused a real mess. Have you tried just tightening the mounting bolts and compressing the current gasket more?

[Mandalay_Parr]

Maybe just tighten the bolts up a little.

[turbojimmy]

The only way to do it right is to remove the A/C unit, and if you're going to do that you may as well replace the $20 gasket. If you try to caulk around it you'll just make a mess (BTDT).

But if you insist, I'd use an interior/exterior type door & window caulk. I've used it before and it peels off easily - at least off of my old-school aluminum roof.