repairing leaks around roof vents

[DanSTL]

Prepping for first time sealing (PO never did in 3 years they had it), and have 6 cartridges of Dicor self leveling sealant at ready. I just noticed my first small leak in December, near 3 way fridge door and open to advice.

1. Can anyone tell what sealant was used here? Especially the dark grey stuff behind the Fiamma awning, seems to be different than rest?

2. Planning to just lay Dicor self leveling over top of caulking which looks pretty good in some places, and remove any loose caulk (but not all caulk if possible). I understand the Dicor self leveling won't stick if it's silicone.

3. Planning to use the plywood method (with shells down).

4. In closing I've heard applying Dicor over top is okay, but curious on pros/cons of this approach and any other tips.

Thanks

[Shane826]

Lap sealant is ok to apply over lap sealant as long as it’s still secure, just cracked. But if you don’t know what the old stuff is, better to remove it all first. Silicone was used for a long time. Nothing sticks to dry silicone, not even new silicone.

[Larryjb]

Where you can, remove the vents and risers, apply new sealant so that it is sandwiched between the roof and riser, and between the riser and vent. This was the only way I could fix my leaks.

I now use ProflexRV sealant. It can be applied in a neat bead, and you can apply over old ProflexRV. Unfortunately, you still have to remove old silicone.

[DanSTL]

Thanks all, based on help and other info here going to knock out front shell edges and center strip only for now. Will strip caulk off edges and center seam with removal tool, mineral spirits, and Nylox brush/drill..then wipe with alcohol before apply Dicor self leveling (and non self leveling for vertical surfaces).

Seems the Dicor isn't as permanent as some of the 3M products, but really like I can just reapply and touch up every few years (and it is garage kept), so hopefully this works.

If not, will remove and reattack center strip next. Believe my 2009 2720QB likely has 3M 760 sealant along center strip, and would consider either that or the Eternabond tape.

Unsure what sealant is around my vents and A/C, but it's very neat and suspect it's not Dicor, so will probably have to take it all out and add Dicor there if small leak by 3 way fridge continues.

[Shane826]

If you’re gonna mess with the center seam at all, just Eternabond it and be done with it. You could actually Eternabond along the edge trim on the sides of the roof, too.

[DanSTL]

Well once I started removing caulk I just kept on going and knocked out 3 vents + antennae too. Now that I think I got the hard part (prep) complete, a few questions before I will apply Dicor self + non self leveling.


Larryjb - Maybe I will have to come back again and remove the vents and risers, but ran out of time/steam. Wondering

-Should I try to remove trip pieces to get these stray pieces of caulk out from the vent and front trim?

I removed enough for the new caulk to join with metal frame and trim, so hoping that is sufficient.

- Is 7 tubes of caulk enough for just the front shell? (Have 4 self leveling and 3 non self leveling)

-Have a trip planned for 28 March (4 hr one way) so held off on the A/C shroud for now, especially because it's very hard to get under the back portion.


Shane826- thanks for the advice on Eternabond. How long have you had yours on? Heard the struggle to remove is huge, and that sun can cause wrinkling of the tape.

Thanks !

[Wavery]

Originally Posted by SMCrane1554

Suggestions for best way to repair leaks around roof vents?

Pretty hard to answer your question without knowing the year of your TM.

A picture of the current calking would be helpful.

If your old calking is pulling away from the roof or vent... ya, by all means, remove the vent and clean the old calking. These razor blades make the job EZ without scratching the roof.
https://www.amazon.com/dp/B08YF7TFJD...roduct_details

Replace the old butyl tape and reinstall the vent.
https://www.amazon.com/dp/B001FCB4JS...t_details&th=1

Then lay down a thick layer of Dicor lap sealant. This stuff is self-leveling. Don't worry about making it pretty when you lay it down because it will flow into a nice uniform contour as it sets.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

If the old calking is just cracked, move on to scrubbing the area to be sealed with rubbing alcohol then apply the Dicor lap sealant above. No need to remove old calking that is still tight to the surface that it's applied to.

NOTE******* Never try to use ANY calking compound over silicone calking.

[Bill]

For some reason, I have an unopened bottle of Motsenbocker's Spray Foam and Silicone Caulk Remover. I don't know if it really works, or if it is one of those "magic potions". It says it is a water-based formula (no fumes) and works by breaking the bond between the caulk and the substrate, rather than dissolving the caulk. Specifically calls out that it removes silicone caulk. Does anyone have any experience with this stuff? Inquiring minds want to know.

Bill

[Larryjb]

Originally Posted by Bill

For some reason, I have an unopened bottle of Motsenbocker's Spray Foam and Silicone Caulk Remover. I don't know if it really works, or if it is one of those "magic potions". It says it is a water-based formula (no fumes) and works by breaking the bond between the caulk and the substrate, rather than dissolving the caulk. Specifically calls out that it removes silicone caulk. Does anyone have any experience with this stuff? Inquiring minds want to know.

Bill

As I understand it (I could be wrong), the only thing that actually dissolves silicone sealant is acetone. Unfortunately, acetone also softens the paint.

Maybe your Motsenbocker stuff will dissolve silicone and not paint? That would be nice.

Larry

[Bill]

Larry -

Again, the ads for the stuff say that it does not dissolve the sealant, but instead, breaks the bond between the sealant and the substrate, allowing you to remove the sealant strip whole. How can it do that? I dunno. Does it really work? I dunno. I'm looking for a guinea pig - er, tester.

Bill