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Preventing RV Roof Leaks (Dicor Maintenance)

Preventing RV Roof Leaks (Dicor Maintenance)


Just about everything attached to the roof of an RV is a potential entry point for water. The TV antenna, vent fans, satellite dish, plumbing vents, solar panel mounts or anything else screwed into, or transitioning through the roof to the interior are places that invite leaks.

The main line of defense against water damage is vigilance — periodic inspection of the Dicor waterproof sealant. Dicor self-leveling lap sealant is ubiquitous in the RV industry, sealing roofs on everything from pop-up trailers to diesel pusher motorhomes and everything in between.

The best way to avoid ever developing a leak in your RV is to check the roof at least a couple of times a year, looking for any cracks in the Dicor. One of the surest signs that an owner is meticulous in caring for their RV is to look for the tell-tale signs of Dicor patching on the roof. Dicor develops small cracks over time, and the periodic application of fresh Dicor to cover those cracks leads to the patchwork look of a well-maintained roof.

Dicor is available at just about any camping supply store or RV dealer, and requires only a standard caulk gun to apply. Before applying new sealant, just clean the area to be patched with mineral spirits. We have a fiberglass roof but if you have a rubber (EPDM) roof, it’s OK to clean the Dicor with mineral spirits. Just go easy on the quantity, being sure not to soak the rubber.


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Bob

Friday 6th of May 2022

I'm removing the old, crusty, cracking Dicor from the very front of my travel trailer where the front cap meets the EPDM roof, it comes off pretty easily by carefully using a heat gun and plastic putty knife. Can I replace it with a new application of self-leveling Dicor, wait a few days then cover that with 6" Eternabond tape, then seal those edges with Dicor? Is this overkill or just smartly adding a second layer of water protection to a sensitive area?

TheRVgeeks

Friday 6th of May 2022

Hi Bob! We love Eternabond, and think it's worthwhile considering using it instead of Dicor in some places. But we'd be reluctant to use both together for anything other than covering something really small, like a screw hole. That's because the Dicor stays pliable permanently, meaning that the Eternabond would be placed over a surface that's able to flex somewhat. It also won't stick well to the Dicor. Over time, those factors could lead to weakening of the tape itself, which we've seen when it's not adhered as flat as possible onto a rigid/solid surface. We'd suggest either going with a replacement layer of Dicor, which is certainly a fine choice, or switching to Eternabond. But we wouldn't do both. By the way, our rig came from the factory with Dicor used in almost every place you'd expect on the roof (around vents, fans, antennas, etc). The only place Newmar used Eternabond is where the front and rear caps meet the roof. Perfect place for a single 8-foot-long, 6-inch-wide strip at each end of the rig. Hope this helps!

Chris

Tuesday 24th of March 2020

Hi Guys! What product do you recommend to seal other parts of the RV. For instance, around the lights or receptacles on the side on the RV. Thanks!

TheRVgeeks

Wednesday 25th of March 2020

Hi Chris! We generally recommend that you contact your manufacturer to ask what they use in that application. Seems like they all have their own preference... or engineering need based on flex, etc. Barring being able to do that, we like ProFlex Clear Sealant (https://www.thervgeeks.com/our-favorite-gear/geocel-28128-pro-flex-clear-rv-flexible-sealant-10-oz/) for sealing things on the sidewalls. It's clear AND UV-stabilized, so it will last. And since it's not silicone, it doesn't cause problems with preventing anything else from sticking. The only down side is that it's not quite as "friendly" to work with as a pure silicone caulk would be, so it takes a little bit more care when applying it (we recommend using painter's tape to mask off the area so that you can apply the ProFlex, then immediately pull up the painter's tape to leave a nice clean, smooth edge). Hope this helps!

MarkV

Monday 14th of January 2019

Great post as always guys!! I also have a fiberglass roof that I clean every six months or so and then seal it with 303 protectant. I do notice that as years go by i can't get it as sparkling white as the previous cleaning which drives me nuts. Do you guys ever reseal your roof with elastomeric paint or another coating from time to time?

TheRVgeeks

Monday 14th of January 2019

Thanks, Mark! Sounds like you’re doing more than we do, as we don’t put anything on our roof. We used 303 once, and didn’t like how slippery it made it... we’re up there too often and it was dangerous. We just power wash ours regularly and get it as clean as we can with regular car wash. We’ve never considered any kind of coating, as we’re not convinced it won’t end up requiring more upkeep over time... and we can live with a not-quite-white roof! ?

Gary Grosser

Saturday 29th of September 2018

Hello RV Geeks, I'm a New to the RV world and I am learning a lot from your videos. I really appreciate them! In one of your episodes that you covered replacing the roof wood after a leak and you stressed inspecting all of your joints and seals for possible leaks.

Now, I've read several articles and watched many videos regarding this same subject. But it occurred to me that no one has ever done a video of what some of the signs would be if a joint or seal was leaking. Although this might be a tough thing to do, would it be possible to make a video covering how to inspect the roof/side joints and seals and things to look out for when inspecting.

Thank you.

TheRVgeeks

Saturday 29th of September 2018

Hi Gary! The only signs we're aware of that leaking is occurring are water stains on the interior walls of the RV, or softness in an area of the roof. The latter symptom is how the owners of the RV in the other video realized that there had been water penetration. We're quite certain that because they had only owned the rig for a short time, it was very well underway during the time the previous owner had the rig. The best thing to do is have a professional pre-purchase inspection done (which theses buyers did do, but it was apparently missed). It can be an insidious problem, and the inspection and touch-up steps we've outlined in this video have kept us dry for over 13 years in our Mountain Aire.

Ken

Sunday 23rd of July 2017

What do you use to re caulk the vertical corner seams of a fifth wheel

TheRVgeeks

Sunday 23rd of July 2017

Hi Ken,

We haven't had to do this on our RV, but we've asked Newmar specifically what we SHOULD use and they told us "Dow Corning 999 Clear Silicone Sealant". So our first suggestion would be to contact your manufacturer and ask them. Silicone is common, but so is ProFlex... and there could be other sealants that we're not even aware of. If you can't get an answer out of your manufacturer, you could also try posting that question to the appropriate brand forum over on iRV2.com. It's free to join, free to post, and there's likely someone out there with your exact coach who has already tackled this project.

Sorry we can't be of more help!

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