I gots the rot...

[willdennis]

Well, shame on me for trusting my RV repair guy to do the inspecting of my roof seals... Found water in the rear toolbox compartment after some heavy rains last month, and then we noticed the bubbling in the rear ceiling near where the wall joins the roof. Got up a ladder when we got home from that trip, and sure enough, the roof is soft from the back seal between the aluminum rear cap and the rubber roof, up towards the front a few inches to about a foot in some places...

So I finally got the time to go up myself, and thankfully the rot is only in the rear - front and center all seem OK, roof good and hard. Looks like the water was coming in around the skylight over the tub, and in some places along the rear seal. So today I stripped off the old sealant from around the skylight, and along the rear seal - in one place, it had completely separated and you could just peel it off for about a foot 😞

So I have gotten one tube of Dicor Lap Sealant (self-leveling) - how much seam can I expect that will cover? (I can get more on Monday if needed.) And how clean does the old seam sealant need to be? (I have scraped off as much as I could, but there's still some left - don't want to risk putting a hole in the roof rubber by scraping too hard...) I saw somewhere you should pre-clean it with denatured alcohol?

Sorry so many questions- I'm really not much of a "do-it-youselfer" but I was too disgusted with my RV guy to let him do it, and I guess "if you want a job done right..."

Thanks,
Will

[willdennis]

Job complete...


Only took one more tube. Now for the rain test, shouldn't have long to wait...

[willdennis]

Well, here's what one tube of Dicor can do...







Of course I ran out before I hit all the screw heads...




Off to the store tomorrow then... Glad the rain's holding off 🙂

[willdennis]

opnspaces wrote:
If the only caulk that you are removing is the same as your first picture then it's not silicone. If you're not going to repair the wood then just peel the caulk back until you get to where it's stuck to the roof, Then lay a new bead down a little wider than the original and call it a day. I would just go right over the old bits that are still stuck as they aren't causing any problems.

Yup, while I'd like to strip and replace all the old rear caulking, I only have one tube of Dicor 🙂 I probably took off a bit more than needed, but I want to make sure I get all the leaky spots. I see there was an previous Dicor patch on the rear passenger-side corner, so I left that run of old caulk there, as well as some other runs around the roof fan front and sides, some of the rear bead caulk that still seemed good & stuck, etc.

We'll see how far I get on one tube - I see it's not supposed to rain now until Tues (but then it looks like solid rainy wx on and off thru the weekend) - I'll get more Dicor if needed on Monday.

[spoon059]

willdennis wrote:
@spoon059,

a) my trailer has an aluminum frame that is screwed together. Yes, the roof plywood is rotted, but the frame should be OK. In testing, I think the walls and floor are OK as well. I do not think the trailer will come flying apart as I run down the road.

An aluminum frame changes things. Rotted ceiling joists and wall studs wouldn't support the forces caused by driving. Non rotted aluminum framing will still support the walls and ceiling. Just be aware that the aluminum frame is sitting on a plywood floor. That water has to eventually go somewhere.

[opnspaces]

If the only caulk that you are removing is the same as your first picture then it's not silicone. If you're not going to repair the wood then just peel the caulk back until you get to where it's stuck to the roof, Then lay a new bead down a little wider than the original and call it a day. I would just go right over the old bits that are still stuck as they aren't causing any problems.

[willdennis]

@spoon059,

a) my trailer has an aluminum frame that is screwed together. Yes, the roof plywood is rotted, but the frame should be OK. In testing, I think the walls and floor are OK as well. I do not think the trailer will come flying apart as I run down the road.
b) no way i'm going to do the work, not qualified, don't have the time, etc.
c) if the cost for someone else to fix is over $1,000, not going to spend that kind of money on an old trailer. I have gotten some "back-of-envelope" cost estimates to let a qualified repair guy to do the job, and we're talking multiple $1,000's. As I said above, blue book value on the trailer is between $4-5K. Not going to sink another couple of $K into it at this point, not worth it. Will sell for best offer, and get another TT, hopefully in a year or two.

I think "Don't let perfect be the enemy of good" applies here.

[willdennis]

Here's part of the problem...



Yup, silicone caulk...

[spoon059]

I wouldn't even waste my time if I wasn't going to fix the rotted and wet wood. Without structure to support it, it will quickly fail again as you drive down the road and wind pressure pushes on the soft wood. Then you will dump your damaged trailer on someone else to deal with...?

Either fix it right or sell it AS IS to someone who knows what they are getting and can do the job right themselves.

[westend]

The first thing I would do if not addressing the rotten wood by replacing it would be to get some "Git Rot", an epoxy, and put it at least on the rotting roof. The Git Rot will at least stiffen up the rotting wood. I'd then treat the wall cavity with an antifungal. Then it can be covered. If you do nothing, all the wood will continue to rot and you just may lose the back end of your trailer.

Eternabond makes a variety of tapes, some that will conform to any curves or edging like Web Seal, which I've used. Web Seal needs to be painted after installation.

None of the Eternabond tapes will adhere to silicone sealant or any of it's varieties. I mean, any trace of it needs to be removed with a solvent. It sounds difficult but isn't. Buy some caulk remover (3M makes a good one), apply it on that mess of old caulk you have and cover overnight with Saran Wrap. Come back the next day and all of the caulk comes off with a rag. Use some acetone to remove any of the caulk film. Apply the tape and roll it with a small hand roller and your waterproofed for a good amount of years. Like said, Eternabond Roof Seal has it's own covering but Eternabond Web Seal needs to be coated.

I used acrylic roof coating to cover the Web Seal tape.
Tape applied around vent and over standing seam, also taped:


Tape applied over roof edge trim:


Finished roof with acrylic roof paint:


Good luck on the repairs.

[willdennis]

Hi @westend,

Definitely not up for tearing off the roof & doing a complete redo, or gutting from the inside... As i said, not the type who would do that myself, and definately not going to pay someone else to do it (at this point, TT is 10+ y.o, and book value is ~4-5K...) I'd like to get one more year (maybe two) out of it before I dump it; it's been a great 1st TT, but looking to upgrade in a year or so anyways... Just want to halt the damage before it gets any worse...

Somewhere I read that Eternabond tape is not what to use on bumpy surfaces... Where the rubber roof meets the aluminum, what with the bead cap and the screw heads, it's definitely a bumpy surface... Would it work if I get it wide enough to go 1" onto the rubber roof (shower skylight and rear bath vent wouldn't allow me to go further forward) and 1" on so onto the rear aluminum, which are relatively smooth, and let the middle part just cover over the seam bead/screws as best as possible?

Here's a pic of the seam:

[westend]

What about the rotting roof sheet and the back wall?

IMO. if you want these kind of problem areas sealed, Eternabond tape is the best solution. Dicor might be good on the skylight but the roof->cap area deserves Eternabond.