Sealant for radius and roof

[dennysbabe]

Getting ready to have the sealant replaced in both sides of the radius on our new to us 2008 Sightseer 34M and Winnebago parts list calls for Manus-Bond (white). That's what is currently on our unit most likely since the factory because it's turning to powder. It definitely needs replacing but has obviously held things together for several years. In reviewing several older posts on this forum I hear about people using Proflex as recommended by AZExpert but in the older posts some don't seem to think it lasts long. When I spoke to a customer care agent at Winnebago he said any kind of urethane. I'm wondering if there is a current consensus on which product is more durable.

Also I couldn't get a direct answer from Winnebago on a product other than Raptor to put on the flat part of the fiberglass roof or even if it's necessary. Definitely not going to do the Raptor. Other than washing the roof regularly is there a need to coat it and if so what would you recommend? TIA

[Ranger Smith]

Just did mine and used eternabond tape. There will be no more issues with sealing it. Went over channel on inside of gutter seam and on to roof. I used the 2" wide black because the edge of the coach is black. I originally sealed it with proflex but it came loose in areas after 1 year.

[KenB]

We are are in process of doing the roof radius on our 2005 Voyage 33V also. I chickened out on just using eternabond and decided to go with Manus-Bond and then after a good cure (30+d) I'll cover it with eternabond.


Wax the roof every year at least.

[creativepart]

Currently, Winnebago has moved on to "Henry's Stone Mason Gutter and Siding" sealant.

https://ca.henry.com/performance-add...siding-sealant

I'm not sure where you can get that in the US. It's seems to be widely available in Canada.

I've been looking at Sikaflex. They make dozens of kinds and this one seems like a decent candidate to me - polyurethane, strong adhesive, stays flexible, made for exterior use:
https://www.amazon.com/Sikaflex-1A-W.../dp/B00461KMIY

I did use Manus Bond 75M for my roof cap corner radius and it's held up very well for 3-years so far. Be aware it's very very messy and sticky to work with.

[dennysbabe]

Winnebago agent did say they had been using Henry's Stone Mason Gutter and Siding but that didn't suggest a replacement product since it's no longer available in the US.

The repair shop that's going to do the work plans to use Dicor Non-Leveling Lap Sealant.

[creativepart]

Originally Posted by dennysbabe

The repair shop that's going to do the work plans to use Dicor Non-Leveling Lap Sealant.

Wow... that's a huge twist. Never heard of anyone using Dicor for this application. Are you confident they know what they are doing? Or is it more "we use Dicor for everything on every RV?"

I checked and it is a Urethane - which is what Winnebago specs. So, who knows?

[dennysbabe]

Originally Posted by creativepart

Wow... that's a huge twist. Never heard of anyone using Dicor for this application. Are you confident they know what they are doing? Or is it more "we use Dicor for everything on every RV?"

I checked and it is a Urethane - which is what Winnebago specs. So, who knows?

I wondered the same thing but a large RV dealer in the area was going to use the same thing when we got a quote from them but of course their quote was a lot higher. I also asked Winnebago about it and they said it was fine.

[cruizerEd]

If you do it the AZExpert/Winnebago way most of the sealant is pushed out.

If you put a spacer in, like a screen door bead or some other small spacer you will get a nice even deep beed that will not drip down into the drainage and will provide a large volume and surface area. The large volume will help with aging as the top of the bead may age but the deeper part is protected. The larger area will provide good adhesion and will not fail as early because it project deep into the channel.

I used ProFlex. It is aging very quickly on the surface but because my bead is deep and wide the small amount of weather hasn't effected the seam at all.

I would not use ProFlex. Sikaflex seems infinitely better. Sikaflex never seems to age. I would not use the self leveling version it might flow and cause problems.

[Dan_S]

I have had good success with Henry HE212. They had it at Home Depot last year.
Dan S

[creativepart]

Originally Posted by cruizerEd

If you put a spacer in, like a screen door bead or some other small spacer you will get a nice even deep beed that will not drip down into the drainage and will provide a large volume and surface area.

Ed, I like this concept… but wonder about it being too secure. We’ve seen others that have screwed down or firmly affixed the Filon to the side of the RV end up with large wrinkles and tears in the roof at the radius. This is caused by chassis flex.

This joint has to remain playable. So pinning the material too much, as I fear the cording would, could lead to more serious trouble down the road.

This is another reason I like the idea of using Sikaflex. As any boater knows this stuff sticks like crazy, is very UV/weather resistant, and stays flexible. (I had a 31’ sailboat with lots of Sikaflex.) I would assume the factory doesn’t use it due to its high cost.

[Bobn1957]

I used Lexel a clear sealant on my radius seams without any problems so far, it remains flexible, sticks to even a wet surface and is stronger than silicone sealant.

[cruizerEd]

Originally Posted by creativepart

Ed, I like this concept… but wonder about it being too secure. .

You are correct that the roof to frame joint must have some flexibility in order to avoid non elastic deformation of the roof material.

I want to clarify that I have not conducted an engineering analysis of the problem, so the following is a high-level analysis of the proposed approach.

The screen door beading is approximately 1/10 of an inch wide and is not adhered to either surface. As a result, it will introduce virtually no rigidity into the system and will only cause a very small decrease in the radius. It is important to avoid using a material that is too rigid to fill this space, as it could lead to problems. By using a flexible material and introducing a 1/10-inch gap, a larger volume is created over which the material can flex in shear. Speculatively, assuming the adhesion has not failed, this larger volume would provide greater flexibility compared to a very thin layer of tightly adhered material.

Perforating the edge of the roof is a particularly poor idea because it creates opportunities for stress concentration at the edges, which could result in cracks. Additionally, using fasteners in these holes could make the assembly too inflexible.

Please note that while this analysis offers a preliminary understanding of the situation, conducting a comprehensive engineering analysis would provide more accurate and comprehensive insights.