found the leak, what kind of caulk do I use?

[decodancer]

I have had an occasional leak in my 1988 Terry travel trailer for some time now. Only shows up during heavy rain (most recently Irene) and drips off the outside corner of a cabinet. The interior ceiling looks perfect. Finally had some time for detective work and looked inside the cabinet with a flashlight for damage. Can see minor warping starting mid cabinet on the wall. At the same spot on the roof there are gaps in the caulking at the edge. It is hard and dry and I can chip out peices with little problem. The rest of the roof looks good, no obvious cracks or damage. I've got two days off to remove all the old caulk but not sure what to replace it with. Hopefully something I can get at the local hardware store. Thanks for your input. Kathleen

[Senior Chief]

Is this old caulk at the trim on the edge where roof meets the sidewall?

If you need to fix this immediately, try removing the screws that hold on the trim piece. If you can, get some gray butyl caulk tape at a local RV or trailer supply. If you can't, pick up some Dicor or C-10 self-leveling sealant at your local big-box hardware place. If you can't find that, any good elastomeric caulk.

NO SILICONE. Repeat, no silicone.

Remove any loose caulk. Apply the new caulk all over in the roof area under the trim piece, including all the screw holes. Replace the trim and screw down with all new screws, preferably stainless screws.

If there is any place the screws won't bite, try a longer or thicker screw at that point, or at worst, fill the hole with caulk so it is not a leak source.

Later you can order some Eternabond tape and apply over the trim to permanently seal this area (see the multiple threads about Eternabond).

Many RV owners have tried the "squirt in a little caulk where you see a hole" type of repair, and it rarely repairs.

As always, JMHO

[njs42]

X2-- with senior chief----drip here---leak way over there where you least expect it---best to begin again. X2 on the products---and nix on silicone.

[decodancer]

OK guys, I'm sure you know what you're talking about but too late in this case. We're expecting lots of rain today so I spent yesterday removing the old stuff (only one side and yes, where the roof meets the sidewall) and replaced it with silacone. Three guys at the hardware store told me that was the best thing to use. Why is silicone a bad choice? I'm willing to start over with the right product, just curious. I know that this may not be the source of the leak but did find an area where the awning attaches near the rear of the trailer. The screw had pulled out slightly so I fixed that and used more silicone around the screw hole. Honestly, I'm afraid to go on the roof (fear of falling through and of heights in general) so trying everything I can do from a ladder first. My coworker was up there a month ago and saw no obvious issues. The roof looks really good but there seems to be air space between the fiberglass and the framing when you push down on it. Is that normal?

[Norm4015]

The guys at the hardware store don't know diddly squat about RVs. Sun (ultra-violet) light decays silicone and it won't adhere to many surfaces and it's hard to remove if it does stick. Silicone "may" work for a year and then you'll be replacing it with the correct RV caulking. Your best bet is to go to a RV dealer and ask them what type of caulking to use for your surfaces and application.

[Senior Chief]

Silicone is a pure-T booger to remove completely when it fails, and it WILL fail. It is simply not meant for outdoor applications. It doesn't work that well indoors either, IMO. Hardware store dudes are not a fund of good information, usually.

Nothing else, including new silicone will stick to old silicone, so your attempts to fix this leak will now include painstaking removal of that silicone you squirted around.

Good luck with that.

As to the fiberglass, you may have a "floating" fiberglass roof, or else the fiberglass has come unbonded to the substrate. Not much you can do about it.

I don't think its likely you will come crashing down through the roof if you go up there, particularly if you take a couple 12x12 or 18x18 squares of plywood up with you and use them to distribute your weight. But...

If you have fear issues with going up on the roof, you'll need to budget the money to have someone else do the maintenance and repair up there. Your roof and AC really needs inspection twice a year & HOPING you won't have leak and repair problems won't actually prevent them.

All the best.

[decodancer]

Thanks for all the great info, guess my rush to get it done will cost me in the long run.
I will bite the bullet and get up on the roof, the plywood will make me feel more secure and damn, I'm not that heavy . Never did rain today so don't even know if my roof repair worked. Spent the day doing interior remodels.