Sunday, May 28, 2023


Service center says wrong sealant on RV’s roof, wants $1000 to replace. What?

Dear Dave, 
On a recent maintenance visit to a local RV service shop, the tech inspected the roof and told me that the entire roof had the wrong sealant on it. He said what was there was “Black Silicone” sealant and what should be there is white Dicor lap sealant. They wanted around $1000 to remove all of the existing sealant and reseal with the “proper” sealant.

The RV was probably a little over a year old when I bought it in 2019, so I doubt the previous owner would have replaced all of the sealant in the short time they owned the RV. I haven’t done any repairs to the roof since I’ve owned it. That would mean that Winnebago sealed the roof with the “wrong” sealant (which I also highly doubt).

I did not go ahead with the suggested work with this dealer because I suspect they are wrong. What are your thoughts on this? What sealant would Winnebago have used on the original roof and what do I need to do to maintain it properly? —Tom, 2018 Winnebago Sunstar 27PE

Dear Tom,
First off, Winnebago does not use Dicor products; rather, they have spec’d the appropriate sealant for the area and material. To me it sounds like a service shop drumming up work with an artificial issue.

What Winnebago uses for sealants

You can find out what Winnebago originally used for a sealant on their website by visiting and going to the owner tab and resources. You will find the sealant guide for your rig here.

Here is the beauty shot of the 2018 Sunstar from the online brochure. Notice the black shroud of the roof air conditioner, the black King Jack TV antenna, and black vent pipes coming up? That typically means they would have used a black sealant such as this picture showing the King Jack on a 2018 Meridian that I just replaced with a Winegard Air 360.


Notice the black sealant used around the base of the antenna. So the comment about the “Black Silicone” is not correct. Here is the actual sealant chart for your rig.

I got the descriptions from my tech contact at Winnebago.

131264-03-03A  Silicone, Black Self Leveling

131264-03-01A  Silicone, White Self Leveling

131264-04-01A  Silicone, Bright White/Sealant/Adhesive Fast Cure

131264-05-01A Replaced by 328744-02-01A Silicone/Sealant Fast Cure Black, -05-02A Replaced by 328744-02-03A Silicone/Sealant Fast Cure – Clear

Most of these are the NUCO brand NuFlex 311. He indicated that most of the sealants used on the roof during this time were black around black components.

If you are looking for the sealant that protects the fiberglass material as it covers the roof to sidewall joint and tucks into the awning rail, that is Item E, part number 090441-04-000, which is a non-leveling sealant so it won’t run all over the place.

So, if the sealant is not cracked, drying out, or separating, and you don’t have moisture penetration, I would not pay the $1000 to have them scrap off the factory installed sealant and install an aftermarket “Dicor” product. Not that the Dicor is bad; it just doesn’t need to be a white sealant when the components are black. I would find another service center as either this one is trying to drum up business or doesn’t know what they are talking about, which could be just as bad.

 You might also enjoy this from Dave 

What sealant should I use on my RV’s exterior?

Dear Dave,
I am starting to see some exterior sealant aging on my RV. What is the best exterior caulk to use? I get so many varied answers from friends, social media.… What does the expert say? —Wallace, 2020 Sunset Trails 18RD Traveler

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


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Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


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Thomas D
1 month ago

Must be nice to have Winnebago on your side. Best advice you’ve given. Using Winnebago part numbers

Sandi Pearson
1 month ago

That service center/tech doesn’t know Winnebago! The roof is fiberglass and they use silicone based sealants. All sealants are not the same, be sure to stick with the brand recommended by the factory. The Winnebago dealer in Forest City is a good source for crossing over Winnebago part numbers. We pay a little more and buy from them because we trust them and they are great to work with.

Michael Roach
1 month ago

$1000 to replace the sealants ? I got an estimate this spring to have my 22 foot Flagstaff TT resealed and it came in at over $3000. No thanks.

1 month ago

I don’t understand why they have BLACK components in the FIRST place! Or even colored ones to match the color scheme of one of the colors used on the side. A white roof and all white covered components would be more logical to have especially when they sit in the blazing sun for hours on end. I guess people want to constantly run their AC’s day and night just to keep the RV comfortable inside causing the RV Parks to raise their daily rates so high to cover the increase in electricity usage and rate increases.

I also can’t believe the number of DARK colored RV’s that I see while running the Interstates. What are the manufactures AND customers thinking? They have GOT to be hotter than hell inside when the AC’s are not running full blast.

1 month ago
Reply to  Dr4Film

Hi Doc. No question the black sealants will heat up more than a white one but the black ones are more stable against UV degredation. Its a catch 22 for sure. I would use white everytime regardless of it’s being less UV stable than the black.

Last edited 1 month ago by Cancelproof
1 month ago
Reply to  Dr4Film

I have commented more than once, here and on other forums, about how dark colors and black absorb and transfer tremendous heat.

My heat gun measurements on a 90F summer day in direct afternoon sunlight measured surface temps on black exceeding 190F! A cream color immediately adjacent was still hot at 130F, but 60 degrees is a huge temp difference impacting ACs and prematurely killing electrical boards in items like powered antennas such as the Rayzor. Same for black or smoke vent covers.

Everything on my roof is white.

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