Roof Caulk Nightmare 2006 T1N/2007 AS Interstate

[Rocinante]

Originally Posted by duckdave

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

Wow! If the installation was bad, I guess no amount of caulk can fix it.

[duckdave]

OK, I exaggerated. It was a mere 7.5 lbs of caulk was removed. I weighed it. More pictures, and questions, to come soon. I think I'll need to do the POR thing sooner than I was planning. That will add a few days to the finished product.

[troubadour1]

Originally Posted by duckdave

OK, I exaggerated. It was a mere 7.5 lbs of caulk was removed. I weighed it. More pictures, and questions, to come soon. I think I'll need to do the POR thing sooner than I was planning. That will add a few days to the finished product.

This reminds me of the snl skit "more cowbell" with Walken. But it's for caulk. "More caulk!"

[68 TWind]

I must confess, my suggestion for the screws and to not use the foam gasket came from an old VAP podcast from many years ago.
To me it just made a lot of sense to increase the surface area under pressure. Counter sunk screws in a plastic flange cause a lot of pressure to be applied in a small area. Keep us posted on the finished project.

[duckdave]

Originally Posted by 68 TWind

I must confess, my suggestion for the screws and to not use the foam gasket came from an old VAP podcast from many years ago.
To me it just made a lot of sense to increase the surface area under pressure. Counter sunk screws in a plastic flange cause a lot of pressure to be applied in a small area. Keep us posted on the finished project.

68 TWind,
Your suggestion might make even more sense today... the 2006-7 unit that was removed had 28 screws, the new unit has only 16 screws . On the negative side, more holes will be made. On the plus side, only a few existing screw holes align and many holes are oversized due to rusting.

So your idea to distribute the pressure over a wider area is even more valid with fewer screw holes.

[rowiebowie]

Originally Posted by duckdave

OK, I exaggerated. It was a mere 7.5 lbs of caulk was removed. I weighed it. More pictures, and questions, to come soon. I think I'll need to do the POR thing sooner than I was planning. That will add a few days to the finished product.

7.5 lbs. of caulk? Why that's only 12 tubes.

Thanks for documenting That's wild!

[duckdave]

OK, out with the old...


Rust Never Sleeps. Looks like I'm in for some POR-15 action for sure now. Reading through InterBlog's excellent blog article about fixing seam-rust on their rig, and reading through the links to Sprinter Forum provided (here). Making a list...


Still seeking an ideal way to remove multiple species of caulking. The outside one was very hard. I had to run the oscillating saw at full speed to cut through that one. What might be the original one, is soft and flexible. It come off pretty easy, but not down to the paint. Then there's plenty of silicone—it is really difficult to remove as it sort of rolls, even in the face of a razor blade. I haven't tried the heat gun suggestion yet. What about MEK? Acetone? (removing a little paint won't hurt right?) I gotta look up Aircraft Stripper—do they carry that in the big box stores?

Will it really remove caulk?

Well, I can't really tell if it's working or not. I guess it's working, cause my rag sure got dirty. I also tried rubbing alcohol (91%) and denatured alcohol. I can't really tell if any of them are working, but it seems to be getting lighter. Silicone is the worst.

At least I have a place to sit more comfortably:

This picture shows from the top the extent of the rust around the opening. It also shows the extent of caulk removal at this point. There is still some caulk there, but the gray stuff is roof paint, I think the brown and white stuff is primer. There's some metal showing through. The black stuff??? Who knows??? Maybe it's mold! No, it's some sort of paint or something that appears to have been sprayed on between some major layers, what's shown here is overspray.

Well, it looks like we are NOT taking the T1N Sprinter Van camping this weekend. Fortunately we still have our '79 AS Sovereign that has not been out of the cave in a year. Think I'll spend today getting it road ready! We are joining our local AS Club in Fayetteville (where my daughter and SIL just happen to live) for a long weekend and will get to attend a Razorback Baseball game. Woooo Pig Sooie.

[InterBlog]

What a nightmare.

I mentioned Marine Forumula Debond in my blog post, but the thing with that product (and probably many other products) is that you have to have a large surface area to volume ratio for it to work. It's really intended for residue removal moreso than wholesale removal of large accumulations. I never found any method other than elbow grease for removing accumulations.

[Rocinante]

Any thoughts about mineral spirits? I've seen it do a nice number on removing recently cured Sikaflex. Don't know what else it might do a number on, so check with experts before using.

[duckdave]

I will try mineral spirits, as I have on hand, thanks for the suggestion. "Mineral spirits" , sounds so benign, but you never can tell what will work. All suggestions welcomed. Thanks!

[Tincampers]

Originally Posted by duckdave

I will try mineral spirits, as I have on hand, thanks for the suggestion. "Mineral spirits" , sounds so benign, but you never can tell what will work. All suggestions welcomed. Thanks!

That’s what I used when I went through this nearly identical test of endurance. It worked really well.

[Alden Miller]

I can't find my picture of my over caulked vent. It had a similar volume that you had. I used a heat gun and putty knife to remove the majority and then stripper to remove the small remainders.

I replaced the caulk with eternabond tape. Now a couple years later the vent has finally died. I have a new one and will be going through what you are in process with in a month or so when we have consistently good weather.

-Alden

[Mansderm161]

Wow..I have brand new AI and its blobbed on pretty heavy on top. I don't see any way someone could caulk over it....maybe that's the point! Now you wonder if previous owner did yours or a service center...if it was a service center, never want to go back there!

[duckdave]

Time for an update!
I've been busy the past few weeks removing stuff (roof attachments, caulk, more caulk, paint, rust) from the roof of my 2006/7 ASI. Here's some pictures showing the most important tools I used:
I became very attached to my ladder.


And my oscillating tool was indispensable.

I used it with a stiff scraper blade for cutting through caulk, and with 80 grit sandpaper for scrubbing off caulk.

I also used a air compressor grinder for scrubbing off paint and rust. A gasket scraper was used to get some caulking off. It was useful b/c it could be resharpened. Plenty of razor blades were used, both to cut stuff off, and held upright and scraped across the roof surface helped get the silicone caulk off. I tried plastic razor blades, and they helped some, but not too much. I didn't worry too much about messing up the paint on the roof because I planed to paint over the messed up parts with POR-15, followed by BUS KOTE for the entire roof for a topcoat. Pretty much following the steps described by InterBlog in her description of fixing the roof on their ASI found here.

Here's a panoramic view of everything cleaned up and ready for POR-15.

The POR-15 steps are:

1. Degrease
2. Metal Prep
3. Paint

Degreasing is basically a fancy term for washing the roof. Since my roof maybe had NEVER been washed, I first washed it with straight up Krud Kutter from that big box depot store.The amount of dirt that came off was amazing! Then I did it again using the special degreaser that's part of the POR system. The process done from the ladder and was to apply degreaser with spray bottle, then wipe it up with a big sponge, and rinse with water from a bucket with the sponge. Move the ladder 4 feet, repeat. Every second time down from the ladder, I got clean water and rinsed the sponge.

Metal Prep etches the metal and leaves behind a zinc phosphate coating to aid in paint bonding. I applied it to exposed metal and rust areas around each roof penetration with a 2" sponge brush, kept the area wet for about 20 min, then rinsed it off as before. I then got worried that I might have failed to remove sufficient amounts of degreaser using my tedious bucket and sponge technique, so I backed the Interstate out of the warehouse and hosed it down, being careful not to run too much water directly into the big holes. I ended up having to mop some up from the inside, but not too bad.

Finally, Paint. This is a significant milestone because now I am adding stuff to the roof instead of removing stuff. OK, POR-15 paint is expensive. I got a 1 pint can and it cost about $35. Per InterBlog's suggestion, I poured it into a 1 quart can for thorough mixing. Then, I poured about 1/3 pint each into two new pint cans and put the lids on firmly. I painted from the quart can, being careful not to get paint onto the paint can rim. I did not want the paint to fuse my lid to the can. I've heard if your not careful you end up having to cut the can open to get to your paint.

Here's what it looks like after one coat of silver POR-15.

I got the second coat on. My lid was NOT fused to the can!. This stuff is tough, tough, tough. Between coats I sanded (thanks oscillating tool) with fine sandpaper. I sanded the roof ribs by hand with wet/dry 320 grit.

A word about Silicone Caulk. DO NOT USE THIS PRODUCT ON YOUR ROOF! First, it is extremely hard to remove. Picture scraping with the edge of a razorblade hard. It is also not compatible with other caulks and paint. I worked very hard to get it all up, but did not succeed completely. Wherever there was a bit of silicone-caulk, it acted like a force field against the POR paint. It actually repelled the paint away leaving a circle of unpainted surface. The folks at POR told me these spots are called fisheyes. They were easy to spot, and the razerblade edge took care of the spots of silicone left behind.

I filled in all the screw holes with POR Patch. It's basically very thick POR paint that comes in a tube. I was able to do this without leaving a raised bump, which is good because it would have been difficult to sand them down, that paint is so tough. This might have been an unnecessary step, but it seemed to me that the fewer holes you have in your roof the better.

Currently I'm in the process of shaping some plastic boards to use as shims around the roof ribs so I have a nice flat surface to mount my Fantastic Fan.

Soon, I be applying caulk of my own!

[thiel]

“Roof Caulk Nightmare” is a great name for a college band.

[wachuko]

Originally Posted by duckdave

...My lid was NOT fused to the can!.

I laughed so hard!!! I have been there!! But with lid fused to the can!!!

Thank you for the update!! Coming along great!

[duckdave]

Progress Report—The Nightmare is almost over.
When I last left you, I had pretty much cleaned off everything on the roof, painted with POR15 for rust and was ready to reinstall removed parts and replacement Fantastic Fan.

The first step in replacing the FF was to come up with some sort of shim to accommodate the roof ribs. Near as I can tell, the original install just used some thin boards to shim up the low spots. 10 years later, these boards were little more than soft sponges, not capable of holding back any water.

I found this video on YouTube that inspired me to use plastic lumber to make my roof shim: Sprinter Van Fantastic Fan Install.

First, I cut the plastic lumber to 1/2" thick x 1 1/2 wide. I don't remember the lengths, but I had two short edges going lengthwise, about 14" long, and two long lengths going across, about 17" long. I removed the texture on one side using a buddy's planer. All fits were checked, double checked, triple checked. I must have done the ladder climb 50 times. I marked where the rib cutouts had to go (shown in the middle photo below), and cut them out with a table saw, followed by sanding and fileing to fit. When all was too my liking, I epoxied everything together using 5-min epoxy and picture frame clamps, and some long clamps to hold everything together. Next day I did some more shaping and fixing until I was reasonably satisfied it would go together.

Next, I drilled holes in the plastic using the fan-base holes as a template. I had to use an extension on my drill bit to drill around the fan dome. Fan-base outline and holes drilled shown in the left photo. Roof side of shim showing cutouts for ribs in center photo. Next, I positioned my shim frame over the 14 x 14" roof cutout (in reality, more like 14.25 x 14.25 cutout) and held it in place with spring clamps (right photo below) and used it as a template to drill the holes in the roof. The old fan had 29 screws, the new one only 16, so basically none of the old holes lined up with the new ones, which was a good thing, b/c the old screw holes were much enlarged due to rust and the trauma of removal.



The next photo shows the installed Fantastic Vent (what they call it, I always call it a Fantastic Fan). At this point, I've caulked everything. I used less that one tube of caulk. I had purchased 6!


Next up, painting...

[wachuko]

That looks amazing!! Great job!!!

[Alex AVI]

Originally Posted by duckdave

Progress Report—The Nightmare is almost over.

Been following thread so I can learn a lot when the time comes. GREAT job DUCKDAVE. Totally pro job. I doubt any rv shop would be so patient and careful.

I suggest after all is finished you change you forum name to FANTASTICDAVE because CAULKINGDAVE is just too lame

[rowiebowie]

Thanks for the update.


A long, hard job for sure. But done right!