To Caulk or not to Caulk?

[marchesi]

Hello everyone,
I took my Bambi to the only RV store in Bozeman Montana and was told that my Bambi needs to be re caulked (is this a word?) around the airconditioner and the Supervent because the caulk seems to be old and ready to give. I don't have any leaks in the inside and some people around here say "if it's not broke don't fix it". The Bambi is going to see her first snow this year with probably a foot collecting on the roof. Could this be a problem with old caulk?
So here it is... To caulk or not to caulk?
Paolo
BTW: I think the caulk is the original from 2004

[Wingeezer]

I would be inclined to think it could be $$ well spent - "an ounce of prevention" and all that!

I suppose to a degree, the condition of the original caulking could be somewhat dependent on where the trailer is stored, but in our case, we bought a used 2005 last Fall and the first thing I did when I got it home was to get up on the roof and check the caulking.

Although there was as yet no evidence of any water leaks inside the railer, I found that in several areas the heavier caulking, - especially around the plumbing vent as I recall - showed deterioration and cracking, so it was due for attention.

When at Jackson Centre to take the factory tour, I picked up the two types of cauling that hey recommend for my year of trailer - likely would be the same for yours. It is Acryl-R for thin seams (ie between alum. panels etc.) and Sikaflex 221 (I think) which comes in regular cartridges for a caulking gun and is used for heavier applications such as roof vents, skylights etc.

The Acryl R is much more fluid and "wicks" into seams. it comes in a can with a screw to lid that screws into a special dispenser that looks like a pump type oil can that you buy as well.

I generally plan to do a walk around check plus get up on the roof at least twice a year to try and keep the caulking in good repair - its a whole lot cheaper than the alternative!

I know this from bitter experience with our last trailer (not an AS) which developed water leaked and required several thousand $ of interior repairs to correct - removing rotted wood etc.


As for AC units, I could well be mistaken, but I didn't think they needed to be caulked.

I thought that they were sealed by means of a gasket that is fitted as part of the original installation, and that if water leaks should become evident, it would likely require removal of the AC unit and replacement of the gasket.

I haven't worked on any RV AC installatons so I'm not 100% sure - be interested to see what others may say in this regard.

I suppose if there were water leaks found around an AC unit, they could be due to weather or could be due to condensation drain tubes getting blocked and the normal condensation from the AC process finding a different route.

Brian.

[marchesi]

Thanks for the info Brian! Yes, you are right, I have been told that the AC has a gasket that only needs to be replaced once every 10+ years. I included pictures of the caulk to give an idea. How should I remove the old caulk? Have you used any products like caulk remover? Do you scrape it off? Which of the two products I should use for these applications? I imagine the Sikaflex 221... And can you walk on the roof or do you need to work from a ladder?
Paolo

[Wingeezer]

To access the roof, I use a ladder gently leaning against the curb side awning near the rear of the trailer, the ladder is so close to vertical that it puts very little pressure on the metal slats that protect the awning.

Once on the roof, I wear clean soft soled shoes and I am very careful to step only on the rivet lines as this is where the roof supports are located. As far as I know, this is an acceptable practice and it seems to work fine!

The one thing you MUST do is to stay off the end caps as they will dent very easily.

I found this out the first time I went up on the roof! The previous owner, or an RV repair person must have been on one of the end caps as it had a fairly big dent not visible from the ground! Luckily I was able to pull it out 95% using a body shop suction puller!

I can't offer too much advise on how to clean up the old caulking. The damage on mine was pretty much the way your plumbing vent looks - cracks opening up in what otherwise looks like fairly solid caulking, so I just filled in the cracks this time around!

Your caulking around the antenna and skylight looks more surface- crazed from UV exposure - might not be that bad.

I think it would be tough to get all the old caulking off. If I were to try it, I would try using something like mineral spirits (paint thinner, not lacquer thinner) and soft tools like popsicle sticks with a chisel end cut into them, or plastic throw away knives.

You might just try cleaning the surface of the old caulking and then filling any obvious deep cracks

I'll be interested to see if anyone has better advice, I'm sure no expert!

I would be inclined to use the sikaflex in the applications you show.

Where I used the Acryl R was around all the rub rails on the trailer, around the window frames, etc.

Because even the newer Airstreams still use wooden floors (you'd think they could use something more durable for the $$!) I am a bit paranoid about getting hidden water leaks that will rot the floor. I did find some open gaps in the rub rail trim around the bottom of the trailer, and the Acryl-R sealed them very nicely.

I you can't find a local source of these products, I think you will find them on the Airstream website store.

[Farmer Dan]

marchesi,
The roof of my '02 Classic caulking looked exactly like your pictures. I was concerned that the weather-checked sealer would leak. I described my scraper solution to bimpy in a post the other day,but will repeat. The best tool was a nylon-like slick product I had gotten from a tile center as a transition piece under a door for my home. It is
1 3/4" X 1/4" and 3 or 4 feet long. Get a handy length and cut a one-sided bevel of 45 degrees or sharper if possible. If it is too wide @ 1 3/4", rip it w/ table saw. A heat gun used carefully will soften the caulking around the roof openings. Work the sharpened "tool" under the caulk a little at a time. This took most of the caulking off. The little pieces left were softened with mineral spirits and "filleted" off with the "tool". A little scrubber pad and the MS removed all traces. If you don't too aggressive scraping it won't even hurt the roof paint. I also removed the vulkem over the windows with same tool. Then I resealed with vulkem running 2-3 beads of vulkem and then smoothing with a plastic putty knife or my finger. ( Resharpen the tool frequently if necessary.)
Dan

[ROBERT CROSS]

Is that grey stuff they used around my black tank vent vulkem?

If so thats the best reason to replace it with something better.

Factory missed a few screws on installation and the grey stuff was badly cracked after two season's.

[marchesi]

Hi everyone,
After receiving some great info from one of our members (sent directly through private message) and asking a few vendors, it seems that the way to deal with old Caulking is to use Dicor Self-Leveling seal that can be bought from RV supply place. You scrape off loose caulk, clean it with soap and water, let it dry throughly and then apply the Dicor right over the old caulk. How is easy is that?
Paolo