Roof Gutter Sealant

For Class A Winne's, the fiberglass roof butts up to the roof rail/gutter on both sides of the MH. Over the years I have seen the sealant fail here allowing water to leak in. Besides typical silicone, is there anything better that should be used to reseal this area?

Same question for sealing windshield leaks.

A lap sealant, e.g. Dicor 501 or Dicor Ultra, works fine (don't use the self-leveling type).  So does Geocel Proflex or Proflex RV.  Or Sikaflex 715. They all remain flexible, which is the main criteria for RV seams.

The gutter/roof rail design does not allow water to enter. That is with or without sealant. The main purpose of the sealant is to keep the fiberglass roof in place.
I applied Eternabond to the rail to end the constant attention that it needed. That is the only long lasting solution that I am aware of.

You mentioned silicone. You do not want to use silicone on a RV as it breaks loose easily and nothing will stick to it when reapplication is needed.
Gary named some sealants that can be used and none of those are silicone.

We have a bunch of threads about roof to sidewall sealants. As far as the windshield, forget it. If it's leaking the glass needs to be pulled, the rust treated and then the glass is mounted according to the latest Winnebago procedure and sealant callout.

Gary RV_Wizard said:

A lap sealant, e.g. Dicor 501 or Dicor Ultra, works fine (don't use the self-leveling type).  So does Geocel Proflex or Proflex RV.  Or Sikaflex 715. They all remain flexible, which is the main criteria for RV seams.

Click to expand...

DON'T use any of that on a Winnebago roof or you will have a major cleanup and restore issue.  A lap sealant will not hold that roof in the gutter and that is a critical seal to continue to be a happy Winnebago owner after a high wind.  Proflex will make sealant replacement agonizing as it does not clean out well.  Winnebago's are unique in that the seal serves as an integral part of the roof assembly, not necessarily for water sealing.  Not a great design, but the design none-the-less.

This is one of the best videos around for sealing the Winnebago roof.

https://www.youtube.com/watch?v=BJz7doxPQXg 


http://www.rialtainfo.com/winnebago/winnebago_images/caulking_&_sealants_roof_sealants.pdf


Ironically, silicone is exactly with Lichtsinn recommends for the painted roof seam.

Didn't mean to jump out Gary - your response is near perfect for any other coach but I've had to be extra-educated on this particular issue.  I have about 2' of clear proflex on mine that not only looks like hell but it's going to get the paint when I remove it.

My 'sperience aligns with what Harry B and Mile High said.  I removed the old, dried sealant from my (used) rig and applied Geocell Pro RV.  In some areas the original sealant was actually missing for several feet in length........but I have never had a water penetration problem.  After 5 months (and about 4500 miles this summer) my nifty-lookin'  Geocell was cracked down the center for almost the entire length of the channel.......luckily the roof does not "give" under the "push in" thumb test in that area; so it is apparently structurally OK, even with the longitudinal crack in the center of the sealant.  I recently tried to remove the Geocell and go with Winnebago-recommended Manus Bond (maybe just another Urethane Sealant?) but after several hours of removal effort, I had progressed about 8 feet or so ............... so I re-filled that section with Manus Bond bond gave it up. 

Next: A 2-inch Eternabond overlay down the entire length.  No real structural strength there, but it should at least shield the sealant I applied from UV radiation damage.  (Some have had this fix in place for 10 years or more....... that would sure work for me.)  My lifesaver: I have a white fiberglass roof (about as white as Eternabond)  The installations I have seen pics of look very "acceptable" but I understand that eventually one will probably see a darker line along the top edge of the tape as its adhesive edge attracts road grime or whatever.

The Eternabond thing can be a little nerve wracking....at least for me.  I have used it elsewhere just enough to know that it is unforgiving of errors; i.e., you don't get to "start over"

I'll try to keep folks apprised of my success...........or lack of it; maybe help someone else decide what approach to take.

Safe travels..............

youracman said:

...After 5 months (and about 4500 miles this summer) my nifty-lookin'  Geocell was cracked down the center for almost the entire length of the channel.......luckily the roof does not "give" under the "push in" thumb test in that area; so it is apparently structurally OK, ...

Click to expand...

Winnebago resealed our roof-sidewall joint and the belt line (the trim right above basement doors) and it cracked after a couple of years. But the "push in" test as you mentioned can determine if the roof-sidewall sealant has failed or if it's just a cosmetic issue. I wish Winnebago's sealant guy could find a sealant that maintains structural and cosmetic integrity.

I took a closer look at the gutter rails and there are 3 holes (about 1/4" square) located at each end and one randomly in between. I was thinking about adding a few more and I can not tell if and debris has blocked up the channel to allow any water to drain if it does get by the sealant. I may try blowing it out to see if air travels freely through it also but I am thinking a few more holes won't hurt. Has anyone added more drain holes?

Looks like a job for 3M 5200, with a UV protectant over the 5200.

3M 4000UV has UV protection built-in. And it has more elasticity (stretch).

It seams these days there are many sealants that are capable to do the job but just as important based on the design would be to make sure if and when ay water leaks by to ensure it has a way out which is not in the MH!

I am going to see if bowing air in one drain hole freely comes out the others, if not I plan to add more drain holes.

This is not a simple Dicor sealant issue and anything like it is absolutely the wrong stuff. If this seam opens up in the right place, you will leave your roof on the side of the road if the conditions are right; there have been posts of exactly that. That seam needs to be LOCKED into its channel with the proper adhesive. I did mine several years ago with the Winne recommended adhesive and it's still solid (The difference is I did it right). Something like 5200 is is ideal and the OEM have similar spec's IIRC, but I don't think 5200 comes in clear tho, so it will show.

5200 is also the right adhesive for rebonding the lousy Winnebago workmanship on the generator and engine compartment doors that break loose from their frame.

As far as the windshield, John is correct... if it's leaking, it's likely rusted through and I guarantee you won't like what you see. I'm in nice n' dry California and never expected to see the damage that I saw when I had the windshields replaced. If it wasn't do difficult to resize pix on a pad I'd post what you're likely to find.

SCVJeff said:

....5200 is also the right adhesive for rebonding the lousy Winnebago workmanship on the generator and engine compartment doors that break loose from their frame.

Click to expand...

I've used WEST system epoxy thickened with one of their specialty fillers to re-bond all of the metal parts that have popped loose over the years.

As far as the windshield, John is correct... if it's leaking, it's likely rusted through and I guarantee you won't like what you see. I'm in nice n' dry California and never expected to see the damage that I saw when I had the windshields replaced. If it wasn't do difficult to resize pix on a pad I'd post what you're likely to find.

Click to expand...

I wanted to see my windshield frame after factory service pulled the windshields at this year's GNR and it was ugly. They wouldn't let me take a picture but I can vividly describe it. The frame was pitted, the worst pitting might have been as deep at 0.5 mm to maybe 1.0 mm. Winnie has a new metal prep system for the frames and a new adhesive so hopefully this will be the last time we have to deal with this.

If you have an easy way to resize pix, I'll send u mine to post. It was really ugly

Jeff - you should have a photo editor packaged with whatever OS you are using.

https://www.youtube.com/watch?v=zbXoyP9d5lI
According to this guy the cause of the rust/leak issues is the molding retention brackets that are install using adhesive strips which absorb water and cause the rusting issue to occur. (Obviously the window metal frame was not treated well to prevent rusting in addition) Once it advances far enough that seal between the window and frame is lost and the leaks start. He states that he uses a different adhesive strip which does not hold water in addition to the rust inhibitor primer that is painted on after the rusted surface has been sanded to clean bare metal.

And I thought the side gutter seal was a PIA! LOL