Roof Caulk Nightmare 2006 T1N/2007 AS Interstate

[duckdave]

Well, it was time to face the music and get up on the roof of my Airstream Interstate to see if I could figure out anything about the water leaks.

OMG!!!!! There must be 50 pounds of caulk up here!!!


There's at least 3 layers of caulk around the Fantastic Vent:


Here, I've stripped down some around the vent


OK, so the Fantastic Vent is an old model 6000A, and it's likely original, as in— installed in 2006. Here's what works: Fan—3 speed, manual open (auto open does not work—stripped gear in lift motor, needs new lift motor), thermometer might work, water detector/auto close does not work. Vent sticks on closing—likely needs new lift arm. Screen missing most screws—needs new screen. Parts here would be around $80.

I'm thinking the aggressive caulking might be due to persistent leak. A possible explanation for persistent leak would be a cracked frame. I've been told that is a "fatal flaw" that requires a new fan. So far, I've not uncovered a crack, but I'm only 1/2 way around removing the heavy caulk to expose frame. If it doesn't have a crack, I can see where it might before I'm done.

I seem to have 3 layers of caulk, maybe 4. Bottom layer might be silicon rubber (stuff that smells like vinegar before it cures), next is a flexible, but tough layer of stretchy stuff. On top is a very hard layer of caulk that come off better with pliers—very hard to cut through with blades or with hammer and chisel. There may be a layer of butyl rubber (black stuff) in there too. The different compounds do not seem to be well bonded together.

I'm thinking of "sacrificing" the unit; i.e., just buying a new one. That could facilitate quicker removal (I won't have to be careful in removing caulk), and once the unit is stripped away I should be able to remove the residual caulk quicker.

Thoughts about this last point? Advice to hasten the job?

As always, thanks for your input!

[Rocinante]

At this point, assuming it’s an option, I would remove / replace that particular not-so-fantastic fan with a new unit. Maybe that nice Max Air fan that has a rain-protection hood that also raises and lowers automatically?

[DBinSD]

I would further recommend that you have done the HARDEST part, now replace the entire fan.

You have to re-sell so, might as well be a new fan!

Good luck, hope you find the culprit of the leak.

Dan

[InterBlog]

No doubt about it - haul that sucker out of there. I did a partial take-down and cleaning of our Fantastic two weeks ago. It's a miracle the thing is even still running. It has already given me rain sensor hell, and I would not hesitate to rip it out of there at the slightest sign of repeat trouble.

Here is my blog post describing my roof caulk job. Rule #1: No layering. Strip everything back before adding more.

What's our current verdict on the best Sika formulation? We'd been using Sikaflex 221 because that's what Lewster recommended. But then someone chimed in on another thread stating that Sika has released a newer formulation.

BTW, Duckdave, you better do those roof lap seams before they get out of control on you. I can already see incipient corrosion, and once it starts, it accelerates. Here is my POR-15 write up, but POR-15 itself was not enough - it doesn't stand up to UV very well. So here is a reminder link to my Bus Kote job. You certainly don't have to use that product, but something probably has to cover the POR-15 or whatever anti-corrosion product you choose to apply to the seams.

Ain't T1N Interstate ownership FUN?!
:-)

[duckdave]

Hey, I've already been to the Camping World and got a new unit, Fantastic Vent 80-3350. It has Auto/Manual lift, 3-speed reversible fan, rain protection and thermostat. Everything but the remote. I also got the Ultra-Breeze cover.

I will have a couple of days before installation, so if anyone has feelings about a better brand/choice I'd be happy to consider alternatives.

I got what sounded like a good suggestion for "de-caulking". My salesman, who admitted not having direct experience, said guys in his shop use an oscillating tool to remove the heavy stuff, then trim off the finer stuff with plastic razor blades. I have an oscillating tool, but for some reason had not thought to use it. I also have plastic razors, but they aren't cutting the heavy!

Rocinante, DeBinSD and Interblog—thanks so much for your comments and suggestions. IB, I thought you might chime in on the corrosion! As soon as I get the major systems usable, I'll tackle the other (important) items. Fortunately, I am able to store indoors, so the weathering should be slowed to some extent.

I'd also like to hear about caulking recommendations. I naively bought just two tubes of Sikaflex 221, I'll likely need more? Seems the stores in my neighborhood (50-mile radius) prefer Dicor, in fact several folks have recommended Dicor self-leveling

[BurntAsphalt]

Wow, from looking at your caulking pics, I'm afraid to get on the roof again and inspect mine! My 2011 AI has a Maxxfan which does a nice job. It is all manual which I also like because I have too many remotes to keep track of already. I also think the low profile smoke tinted integrated hood looks better than the Fantastic Fan hood. The only issue I've had with mine was the lifting gear broke but it was an easy repair.

[Lily&Me]

It looks like someone caulked over caulk over caulk, rather than scraping it down to the bare metal each time.

Depending, in addition to all the caulk, there may be poor installs of vents and the Fan that may have been covered with caulk rather than done properly...we found those on our roof, leaks not resolved until the vents and Fan had been redone from the bottom up.

Take your time, and a good look at what’s under all that caulk.

Good luck,

Maggie

[perryg114]

Sometimes Aircraft Stripper of Zipstrip Gel will soften that caulk if you can't get it off. I don't like anything made of plastic on the roof especially things like vent frames because they crack and leak. Vintage Trailer Supply has metal sewer vents and air vents. Plastic lids can be replaced without replacing the frame but those will also crack. Also check are door and window frames for problems.

Perry

[InterBlog]

There seem to be a fair number of MaxxFan fans out there. I myself have not done the research. I'd look for whichever was the quietest. From the pictures, the MaxxFan units appear similar to Fantastics, so I wonder if the noise varies much.

As with every RV component, I have to ask the question: Is there a higher-end third option on the market?

[DBinSD]

Depending on the caulking used, Rubbing Alcohol has worked well for getting the remaining "pieces" that really stick.

With Sika products (probably others as well) it is very important to have a very clean slate. Use a small hole in the tube as it can get messy, take your time.

[twobikes]

Oscillating tool +1. !! After taking the bulk of it off like a recruits boot camp haircut, you won’t mind the little scraping with plastic scraper and solvent. The tool will catch a corner and scratch the white paint a little bit , but it covers with your pristine new caulk...

[wachuko]

Originally Posted by InterBlog

...BTW, Duckdave, you better do those roof lap seams before they get out of control on you. I can already see incipient corrosion, and once it starts, it accelerates. Here is my POR-15 write up, but POR-15 itself was not enough - it doesn't stand up to UV very well. So here is a reminder link to my Bus Kote job. You certainly don't have to use that product, but something probably has to cover the POR-15 or whatever anti-corrosion product you choose to apply to the seams...

Agreed!

Duckdave, from the photos it looks like it all requires some TLC to avoid problems in the near future. I would also recommend using Silver POR15 and then coated with something to protect it from UV rays. As InterBlog mentioned, POR15 is a great product but needs to be coated if expose to the sun.

[68 TWind]

Careful use of a heat gun really speeds up caulk removal.

I have the same FF you just purchased and have been very happy with it for several years.
On my fan, they may have changed it, the holes in the flange were countersunk for the countersunk screws included in the box. Don' use them. Instead get pan head SS screws of the same size, ( #8 or #10- I don't remember) and SS washers. This will spread the pressure over a much much bigger area when you tighten them down as opposed to the small contact area in the countersink. This will help prevent cracks from starting which used to be a common problem. I did not use the foam gasket but instead a good bead of Vulkem, been 7 years and no leaks.

[InterBlog]

Originally Posted by duckdave

...IB, I thought you might chime in on the corrosion! As soon as I get the major systems usable, I'll tackle the other (important) items. Fortunately, I am able to store indoors, so the weathering should be slowed to some extent....

Your attitude is refreshing. You are taking it all in stride, whereas other T1N Interstate newbies have been known to melt down upon realizing just how much labor their vehicles are going to require.

To an extent, I understand this reaction - people buy older Interstates to camp, not to have as labor-intensive driveway ornaments. But the inescapable fact is that these are ten-plus year old vehicles. This kind of work comes with the territory.

[duckdave]

Originally Posted by InterBlog

Your attitude is refreshing. You are taking it all in stride, whereas other T1N Interstate newbies have been known to melt down upon realizing just how much labor their vehicles are going to require.

I just spent about 4 hours up on the roof. My attitude now needs serious adjusting!!! I did not even manage to get the old one off yet. My idea to use the oscillating tool worked a bit, but the "caulk removal tool" was too flexible; I bought a more rigid one on my way home. I managed to finesse all but 4 of the rusted head screws off. I might go after them with a Dremel tool tomorrow.

I also realized that the 14 X 14" fan hole spans two raised ridges on the roof! Too early to tell for sure, but I don't think the installers (Airstream, I presume) bothered to build a base to support the unit, they just filled the gap in with caulk.

Interestingly, the new Fantastic Vent fan comes with very minimal installation instructions. And they recommend installing the fan using a provided closed cell gasket, and just caulking the edges and screw heads with silicon.

Much of the caulk is silicon caulk, which is very difficult to remove. It just sorta rolls in the face of a razor blade. There's also a soft, very stretchy caulk, and a hard as a rock caulk. Oh, joy!

68TWind: good call on the screws. I'll need to get longer screws anyway. The screws coming out are in very bad shape, zinc I'm guessing. Well, they have been up there 12 years...

perryg114: Aircraft Stripper or Zipstrip Gel? Would either of these strip the paint? Don't want that!

DBinSD: Rubbing alcohol. That's isopropyl alcohol. I have "Denatured Alcohol" which is ethanol with something poisonous added to discourage drinking. I may have to try both.

wachuko: Yeah, I've already added POR15 to my to do list.

Thanks, all.

[InterBlog]

Originally Posted by duckdave

I just spent about 4 hours up on the roof. My attitude now needs serious adjusting!!! ...

Podcasts are great for tedious work. I made a weak attempt yesterday to be Jordan B. Peterson's one millionth YouTube subscriber. However his fans pushed him over that milestone in the middle of the night, and I wasn't willing to sacrifice any sleep to my bid.

[duckdave]

Caulking Battle UPDATE:
I have now managed to get all 28 screws out, or broken off. In the process, I have determined that wood shims were used to accommodate the roof ridges. Today, that FAN will be OUT OF THERE, or BUST.

Comments are sought re: installation of new ceiling fan/vent (Fantastic Vent model 3350).

Instructions obtained from the company recommend the use of a closed cell gasket (provided, looks like packing material!) between the fan flange and roof (no sealants mentioned). Screw the unit down utilizing all 28 screws, evenly. Then apply sealant (they recommend silicone) to edges and screw tops.

My plan: I need to fashion a shim to accommodate the roof ridges. I plan to make the shim using plastic lumber per this persons YouTube (shim fabrication starts at 7:45). Shims will be 1/2" x 1 1/2", trimmed to allow for ribs. I don't plan to use silicone per advice from several on this forum. But, I don't think Sikaflex 221 sticks well to plastic lumber. So, I plan to do it per the YouTube video referenced above. Put a layer of butyl tape under the shims, and between the joints. Place shims around cut-out.

This is the part I'm less sure about: Should I follow Fantastic Fan's instructions and use the closed cell gasket? That's the way the video did it. Just use the supplied gasket, top with fan. Drill and mark for holes (hopefully they will align with existing holes!) and screw it down, using Stainless Steel #8 x 1 1/2" sheet metal screws. I am still undecided whether to use oval head screws, or to use pan head with washers per 68 TWind's suggestion. I will top everything off with Sikaflex 221 around the seams and screw heads.

Ok, off to the trenches...

[Lily&Me]

Fantastic Fan gives reliably good instruction, and talked my late husband thru via cell phone the new install of ours...he on the roof, not very handy, cell phone in hand.

There is a wooden frame piece between the outer and inner vehicle frame that you should take a look at before you install the new fan....mine was found during re-caulking to be rotted a couple of years ago, causing screws to have loosened and the whole thing with potential to go flying off whilst driving down the road.

It was replaced, the fan then properly secured.

There are pictures and a fuller discussion from others on the Interstate Maintenance & Upkeep thread, if you want to look at that for more information.

Maggie

[duckdave]

OMG, in addition to the 25 lbs of caulk on the outside, there’s another 20 lbs on the inside!

[InterBlog]

Sikaflex 221 adheres to many things. I’ve used it to seal the brick face on our house where the a/c condenser lines go up to the attic. Sticks to brick, copper, rubber, and closed cell foam in that application.