Which Roof sealant is better?

[SantinoDad]

I have a 2016 Winnebago Minnie Winnie 22R that has developed a leak in the nose cap area. I called Winnebago about which aftermarket sealant they recommend and was directed to Manus-Bond 75-AM XTREME Ultra Clear.
The shop that is doing the prep and reseal of my rig's roof/nose cap area is showing Dicor as the sealant.
Is Dicor acceptable or should I insist on Manus-Bond?

[edge68474]

75-AM Ultra Clear

Looks good to me. Nothing wrong with Dicor either. Dicor is very popular


Removing the old sealant and doing a VERY thorough cleaning is VERY important.

[ftodaro]

Just to be clear are we talking about the joints that are on top of the roof where the cap meets the roof, a horizontal surface? is this a fiberglass roof? if yes to both dicor is a populate and acceptable product. IMO, the manufacture will recommend what they used during manufacture which in my case was a silicone base product. I did NOT use silicone on my reseal, I used dicor. Why? Silicone is a great product and lasts a long time on the original install but on reapplication it is a bear to work with. You have to remove 100% of the silicone residue before reapplication because nothing sticks to old silicone. With Dicor you can apply new over old and makes repair easy. Its also easy to remove if you want to start with a fresh coat. At the end of the day all you want is a water tight seal. Dicor will do that on a clean surface. I do not know if the product they recommended is silicone, I am just saying that using an after market product is fine.

[NCY-UFO]

I always use elastomeric on all the seams. Never had any water problems, Check annually...

[bevandtomH]

If the seams are not seen from the street, you might consider Eternabond Tape
With minimal prep you can go right over existing sealant with no issues
Available on Amazon

[youracman]

Originally Posted by bevandtomH

If the seams are not seen from the street, you might consider Eternabond Tape
With minimal prep you can go right over existing sealant with no issues
Available on Amazon

^^^^^^^^^^^^ X2 ^^^^^^^^

Not all agree, of course ..... but you might want to consider it.

On that seam: I "knocked down" the old chalky sealant that was applied (and re-appplied) by the PO of my coach and then applied 4" Eternabond tape using their cleaner and a hard rubber (2") roller (pressure is your friend). After prep, I had about an inch or so of "virgin" fiberglass (Filon) for the EB tape to adhere to (fore and aft.) It has been up there 5+ years now and looks almost like the day I applied it. Works for me. I did stop the EB tape at the roof cove edge so it can't be seen from the street and I work non-sag Dicor into that area.......it needs touched up annually (maybe a lot of movement there from traveling or maybe expansion and contraction?)

I have also used self-leveling Dicor around the sewer vents and it performed well. Seems like I have to touch it up (after cleaning well with mineral spirits) every couple of years.

Good luck on your project and safe travels to ya.

BTW- If you haven't already done so, watch a "bunch" of AZ Expert youtube videos re WBGO roofs. You will then know a LOT about WBGO roofs (I think they are good design, personally ..... just don't slack on maintenance.)

[BCam]

AZ Expert has been using Pro Flex RV Sealant for the caps and roof seams. While you're at it, make sure your roof's radius seams are inspected. I suggest you watch this video before proceeding with any decisions:

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

Note, Dicor is a sealant while both Manus Bond and Pro Flex have adhesive properties that Dicor doesn't.

[edge68474]

Good video. Thank you for sharing it with us.

[BCam]

Like youracman, I've used Eternabond tape on my roof and have been happy with the results. Before applying you need to make sure that everything is well sealed. It has very little tensile strength so shouldn't be counted on to hold things together.

Be advised that it is a pain to remove. Once the outer protective layer is removed, the adhesive layer is very difficult. There are numerous Youtube videos and other links on how to do this. The good news is, if you're going to reapply, you can put new tape over the sticky residue.

AZ Expert doesn't like Eternabond and shows videos of where it's deteriorated significantly and has to be removed. I haven't experienced this in our California sun but he's in Arizona. I also suspect that some of what he's seen might not be Eternabond but some look-alike.

Here's another AZ Expert video, this time regarding Dicor on Winnebago roofs:

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

[Mudfrog]

Ours is an 03 Itasca and still has almost all the original sealant in place. I do routine checks and have only had to reseal the joint where the front cap meets the fiberglass above the side windows. Everything else is still pliable, adhering fine, and in great shape. Because of this, I'm gonna try my best to use what Winnebago used when they built our rig when it does require new sealants.

Here's a pdf showing the part numbers of the sealants used on the 2016 Minnie Winnie. It does not give names of the different sealants but you can search the part numbers and find the correct products.

22R Sealant Callout Sheet

[BCam]

Originally Posted by Mudfrog

Ours is an 03 Itasca and still has almost all the original sealant in place. I do routine checks and have only had to reseal the joint where the front cap meets the fiberglass above the side windows. Everything else is still pliable, adhering fine, and in great shape. Because of this, I'm gonna try my best to use what Winnebago used when they built our rig when it does require new sealants.

Here's a pdf showing the part numbers of the sealants used on the 2016 Minnie Winnie. It does not give names of the different sealants but you can search the part numbers and find the correct products.

22R Sealant Callout Sheet

One of the advantages in sticking with Winnebago's recommended sealants is that you're ensured that there won't be a compatibility/adhesion issues between the old and new sealants. I mentioned Pro Flex since I know AZ Expert uses it and, based on his videos is careful about such issues.

[NeilV]

Originally Posted by SantinoDad

I have a 2016 Winnebago Minnie Winnie 22R that has developed a leak in the nose cap area. I called Winnebago about which aftermarket sealant they recommend and was directed to Manus-Bond 75-AM XTREME Ultra Clear.
The shop that is doing the prep and reseal of my rig's roof/nose cap area is showing Dicor as the sealant.
Is Dicor acceptable or should I insist on Manus-Bond?

Dicor is not usually acceptable except for around an antenna or vent that is screwed down securely. The Manus-Bond is a Urethane Adhesive with much stronger bonding properties than the Dicor Sealant. That said a competitors Urethane Adhesive Sealant with similar specifications would be the only acceptable substitute.

Be wary of old stock on the Urethane Adhesive Sealants as most only have around a 9 month shelf life after the date of manufacture after which they loose too much of their solvent base and won't flow or bond as well.

[BCam]

Originally Posted by NeilV

Dicor is not usually acceptable except for around an antenna or vent that is screwed down securely. The Manus-Bond is a Urethane Adhesive with much stronger bonding properties than the Dicor Sealant. That said a competitors Urethane Adhesive Sealant with similar specifications would be the only acceptable substitute.

Be wary of old stock on the Urethane Adhesive Sealants as most only have around a 9 month shelf life after the date of manufacture after which they loose too much of their solvent base and won't flow or bond as well.

I would add a bit to Neil's post and expand on my previous comments. The commonly used Dicor is a "lap sealant" that is formulated to be used on top of fixtures to cover over the mounting screws, seal the edges of fixtures, etc. It's available as a self-leveling version for flat surfaces and a non-self-leveling version for vertical surfaces. It's not designed to be used under fixtures, caps, etc. where adhesive properties are needed. It's also primarily formulated for use on EDPM and TPO (rubber) roofs, not fiberglass roofs like your's.

If you check out the sealant call-out sheet for your MH, you'll see that in most locations, two or more sealants are specified. Generally, one is used under the fixture and another on top. Here's a link to a Winnebago "Service Guide" should help you understand the nature of the different Winnebago-specified sealants.

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

Winnebago's "Sealants Call-Out Sheet" for your MH:

https://www.winnebago.com/Files/File.../000210036.pdf

You'll note that, for the front cap, the call-out sheet specifies Sealant C = 185987-03CHT, which, per the service guide, is a polyurethane based sealant. This has the necessary adhesive properties that are missing in Dicor. A little Googling will cross-reference this part # to Manus Bond 75AM, which is the same brand name that Winnebago gave you. The front cap requires both adhesive and sealing properties which are provided by Manus Bond 75AM. Using Dicor in this area is inappropriate. To properly reseal the front cap, it needs to be resealed between it and your roof, gooping sealant on top of the joint isn't enough.

As I noted previously, AZ Expert has begun to use Pro Flex RV Sealant instead of Manus Bond 75AM for these applications. I can't personally vouch for this substitution but AZ Expert has a ton of experience with Winnebago roofs and I don't think he'd use something inappropriate.

Here's another video about not using Dicor on Winnebago fiberglass roofs:

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

[ftodaro]

Bob C

The I watched the video you posted. Nothing sticks to silicone residue. Silicone will not stick to silicone. If you disagree test putting silicone on top of silicone and tell me if it sticks. I agree that Dicor is not a proper product to securing fixtures but it is acceptable IMO for waterproofing horizontal joints if the surface is properly prepared. In my case after extensive cleaning I also ruffed up the surface. You would need to do the same thing when using silicone. To each his own as they say. I did my rig 4 years ago and it has adhered and stayed dry.