front/rear caps to roof seal

DanGlo52 · 05-05-2022, 10:08 AM

Re: 2004 Winnie Vectra 40 AD.
Good morning folks. I need advice from those who have already done this work. My seals at the front and rear caps to the fiberglass roof appear to be cracking and deteriorating. It is time to attend to this before it becomes a huge problem and leaks. I was thinking of stripping out all the old and cracked caulking, replace with Dicor self leveling lap sealant then cover the whole seam joint with a 4 inch Eternabond tape from left side to right side to make sure that everything is good and well sealed. Has anybody done it this way? Do you know for sure that this is a good fix or should I be doing something else. I thank you for your thoughts and especially your experiences.

BobC · 05-05-2022, 02:18 PM

1. Don't use Dicor, it's formulated for use on rubber, not fiberglass roofs. It won't cause damage but would be less effective than the sealant specified by Winnebago. I'd use the sealants specified by Winnebago in the sealant callout sheets.

2. There are two sealants involved, one that's underneath the cap plus a self-leveling sealant on top.

Front Cap:
Sealant A: 072889-10-000 which cross-references to Manus Bond 75AM, White
Sealant B: 131264-03-01A which cross-references to Nuco 311 Self-Leveling Silicone

Rear Cap:
Sealant B: 131264-03-01A which cross-references to Nuco 311 Self-Leveling Silicone
Sealant C: 094401-04-000 which cross-references to Manus Bond 75AM, Clear

I'm not familiar with your MH so I'm not sure why the rear cap needs clear Manus Bond.

3. I agree with using Eternabond.

4. If your caps are problematical, have you checked your roof edges? They may need attention as well. These also use Manus Bond 75AM

Sealant Callout Sheet: https://www.winnebago.com/Files/File..._s_sealant.pdf

And here's a Service Tip on Winnebago sealant callout sheet:

https://www.winnebago.com/Files/File...t%20Sheets.pdf

Here are two videos about not using Dicor on Winnebago roofs:

https://www.youtube.com/watch?v=14XxkXlMGDA

https://www.youtube.com/watch?v=lAsMySfJb0Q

**creativepart** · 05-05-2022, 02:33 PM

I put Eternabond tape across my front cap seam. I kind of wish I hadn't done so because it's so difficult to remove. But it's doing the job fine.

I had a small leak coming from above the driver's side window. I was on a trip and didn't want to dig too deep into finding the leak. So, the quick response was to put Eternabond all across that front cap joint.

But the leak continued so I slowed down, did a full examination and found a gap in the caulking on the side of the cap where it joins the side of the RV body. When I got home I got some Manus Bond 75, cleaned out the area and fixed it properly. No more leak.

The Tape wasn't really needed, and still isn't but it's on there, it's difficult to remove completely and it's not hurting anything. So, there it remains.

BobC · 05-05-2022, 04:27 PM

Quote:

Originally Posted by creativepart

I put Eternabond tape across my front cap seam. I kind of wish I hadn't done so because it's so difficult to remove. But it's doing the job fine.

I had a small leak coming from above the driver's side window. I was on a trip and didn't want to dig too deep into finding the leak. So, the quick response was to put Eternabond all across that front cap joint.

But the leak continued so I slowed down, did a full examination and found a gap in the caulking on the side of the cap where it joins the side of the RV body. When I got home I got some Manus Bond 75, cleaned out the area and fixed it properly. No more leak.

The Tape wasn't really needed, and still isn't but it's on there, it's difficult to remove completely and it's not hurting anything. So, there it remains.

It is hard to remove but, if you're going to reapply the Eternabond, you don't need to remove the sticky stuff, just the top layer. I had to completely remove mine from over the windshield when I had to have the windshield replaced. Messy but doable.

wyocamper · 05-05-2022, 04:45 PM

I've had to replace my TV antenna and the bathroom vent fan, both of which were taped pretty good with Eternabond. A heat gun and some patience and it came off fairly easily. The previous owner had pretty much sealed everything on the roof with Eternabond tape.

DanGlo52 · 05-05-2022, 04:53 PM

Thank you Bob, it appears that you have saved me from making a very grave error. I shall order the Manus Bond. Do you happen to know the required amount to seal the cap up properly right across? I guess I will order some white and some clear to follow the callout. I will probably still want to seal it also with the 4 inch eternabond to make it a permanent fix. Your comments are much appreciated!

Ray,IN · 05-07-2022, 03:06 AM

I had my front cap joint resealed a few years ago. They used regular Dicor non-sag sealant to fill the gap, then finished with Dicor self-leveling after the first application had time to cure a few days.

BobC · 05-07-2022, 09:17 AM

Quote:

Originally Posted by DanGlo52

Thank you Bob, it appears that you have saved me from making a very grave error. I shall order the Manus Bond. Do you happen to know the required amount to seal the cap up properly right across? I guess I will order some white and some clear to follow the callout. I will probably still want to seal it also with the 4 inch eternabond to make it a permanent fix. Your comments are much appreciated!

You'll want to remove all caulking on top and over the edge of the cap. Then inspect the sealant that's between the cap and the roof. That's the critical place. If it's failed, it will be dirty and/or you'll see that it's coming loose. I don't know how far it penetrates, but you'll have to dig out as much as you can.

Clean it well, finishing off with acetone and apply the Manus Bond. There's no need for the Manus Bond to extend out over the roof, it's what's between the cap and roof that counts. Let it dry and finish off with a layer of Nuco 311, lapping over the top and onto the roof about an inch each side or so. The Manus Bond has adhesive qualities that the Nuco doesn't. Nuco 311 is self-leveling, which Manus Bond isn't. The Nuco's function is to protect the sealed joint.

Alternatively, you can skip the Nuco 311 and use the Eternabond Tape. That's what I did. I also think it looks neater than the globs of self-leveling lap sealant as applied by the factory and others. I've seen it described as seagull "S***".

I come from a sailboating background and boats don't use lap sealant but rely on neat applications of sealant between the fixture and the deck. A sailboat deck is subjected to a lot more abuse than an RV rooftop. I can only surmise that the use of lap sealant in the RV industry is primarily to cover up and protect sloppy work.

Here's a boating link that describes the process you'll use for the Manus Bond:

https://www.boatingmag.com/seven-tip...arine-caulk-0/

With regard to Ray,IN's comment about Dicor, I don't know who "they" is but it wouldn't surprise me that a dealer or other RV shop would use Dicor. It simplifies things to only stock one type of sealant. To many, Dicor is the only manufacturer of RV sealant. Their brand recognition is second to none. As I mentioned, it won't cause damage, it's just not the best choice.

It's my understanding that Winnebago specifies Dicor for their towables, which have rubber roofs as opposed to the fiberglass (Filon) roofs of our MHs.

Wyatt · 05-07-2022, 10:46 AM

This is all good info Bob. I have a rubber roof so I use the decor line of products, but they don’t last long so I’ve coated the lap sealant on mine with flexseal and they look brand new after two years.

BobC · 05-07-2022, 12:08 PM

Quote:

Originally Posted by Wyatt

This is all good info Bob. I have a rubber roof so I use the decor line of products, but they don’t last long so I’ve coated the lap sealant on mine with flexseal and they look brand new after two years.

I didn't realize the Intent had a rubber roof. I see from another post that the Outlook does as well.

Ray,IN · 05-08-2022, 10:51 AM

I forgot to say, my front cap has such a large gap on each side they used backer rod in the gap first so the Dicor had something to prevent it from going in too far. The gap was so large it would have never filled up without the backer rod.

That was 6 years ago, no leak since.

BobC · 05-08-2022, 12:36 PM

Quote:

Originally Posted by Ray,IN

I forgot to say, my front cap has such a large gap on each side they used backer rod in the gap first so the Dicor had something to prevent it from going in too far. The gap was so large it would have never filled up without the backer rod.

That was 6 years ago, no leak since.

If you can find the right size, the rubber "spline" used on screen doors will work for this. If they're too small you can twist two pieces together.

Jim_HiTek · 05-08-2022, 06:10 PM

I just cleaned up the caulking a bit, front and rear seams. Washed, than used a solvent wipe. Then covered it all (seam and remaining caulking) with 4" wide Eternabond tape and sealed it over the edges of the RV on either side too, down to the rain gutter (~6" is all). Didn't try to scrape off and replace any of the caulking, just removed any small bad sections or over pours. Some areas had to cut off big lumps. The Ebond stuck fine to any areas that didn't have the caulking and not to bad on those areas that did have the caulking.

Here's how it looked the first install:

That was in 2016 and I did have to replace much of that rear Ebond seal because I'd originally installed it during wet weather. It puckered up and the road wind slowly lifted it up from the seam. Wasn't hardly any job at all to pull it up off the seam, clean a little again, than relay new Ebond. Easy. Thing was that since I'd left the original caulking up there, no leaks even as it pulled up over time. The Ebond is like a 2nd layer of protection that doesn't need maintenance.

Also installed 2" Ebond down either side of the RV to prevent the roof from pulling up and off when the caulking fails...which it had started to do. With the Ebond there holding the roofing material in the channel, I've not had any leaks and don't have to maintain it. Once down, Ebond stays put (for the most part, note that racking the RV repeatedly will pull Ebond off the roof edges). Still looks great, btw.

Here's how it looked after install. Looks the same years later:

Here's a link to my ad free blog stories about the roof: Roof and Roof Items...

AFChap · 05-11-2022, 04:40 PM

The original Manus Bond & Nuco 911 have done a great job for 18 years. Replace them & you're ready for another 18 or so. I see no need for the additional expense & effort of adding Eterna Bond.

Ray,IN · 05-19-2022, 04:26 AM

Quote:

Originally Posted by BobC

If you can find the right size, the rubber "spline" used on screen doors will work for this. If they're too small you can twist two pieces together.

Not a chance; the gap was approx. 3/8" wide, 1/2" dia. foam backer rod filled the gap perfectly, pushed it back in approx. 1/4" and filled with Dicor sealant.