Saturday, December 9, 2023


The real reasons why RV roof sealants are failing

Want to know the real reasons why roof sealants are failing and leaking?

First, during production the manufacturers are building the coaches within three days (in most cases). They are using a minimal amount of sealants so that the unit can quickly dry and be transported for sale.

Also, in order to save time during production, the fasteners and screws are being installed with impact guns. This damages the integrity of the structure they’re being secured to.

Multiple shortcuts are used, including screws being missed in multiple precut holes and the ends of moldings for security and a finished looked. Moldings are often being cut short. When the unit flexes, it causes the moldings to separate from the thinly applied roof sealants.

Now, what owners need to be aware of! All roofs require maintenance—it doesn’t matter if the unit is stored inside or is exposed to the elements.

What they don’t tell you is that the roof sealants need to be cleaned as well as the roof membrane. If you are cleaning the sealants and cleaning and treating the membrane, the roof and the sealants will last a lot longer. When sealants heat up, the oil in them bleeds out and then dust and dirt stick to them. This causes the sealants to shrink, crack, separate and lift up. This is what causes your roof to leak.

Just like an ink cartridge

Lastly, we have all bought a printer at one time or another. It comes with a starter printer cartridge and the starter cartridge does not print that much. The next thing you know you’re out of ink and it’s time to go down and buy that expensive ink cartridge. This is the same situation after a little while with the roof. Because of the above issues, the roof will require to be thickened up or completely re-sealed. If this is not done, then your roof will leak and it will cause damage. Just like the air in your tires getting low and it’s your responsibility to fill them back up.

Brands of RV roof sealants

There are basically two main RV sealant brands out there: Alpha and Dicor. Keep in mind that for years both brands have been used on all roofs. We only use Dicor. Why?

Because other brands have adopted different chemical regulations, this causes their brands to fail to self-level, and not to adhere to roof surfaces. This also applies to the glue used on the roofs.

Wonder why RV roofs lift in travel? The same thing applies: They have changed the chemistry of the glue. (It’s not sticky).

So why are RV owners jumping on the EternaBond tape wagon and other brands of roof tape? Because influencers are advising you and pushing their products. Oh, it’s so great… NOT!

Did you know that the tapes don’t seal off the air from inside or outside the units? As the interior air pressure rises and hot and cold air attempt to force itself out of the gaps, it causes the tape to lift, allowing condensation underneath.

Be safe, have fun, and keep up with your maintenance.

DIY product links:

Thank you,
Dustin Simpson

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Dustin Simpson
Dustin Simpson
With over 25 years in the RV Industry, Mr. Dustin Simpson has worn many hats. From an RV Technician, Warranty & Parts Administrator, Parts & Service Manager and Business Owner. Outside of these typical roles and responsibilities within the industry, Dustin enjoys being a Content Creator, Brand Ambassador, Author, and Expert Witness. He has served as an expert witness in multiple cases in California, Washington, Idaho, and Texas. His repair facility has been servicing customers at the same location since 2003. What sets us apart from the dealerships is we are here to fix and maintain what you have, and not sell you a new one. Whether you own a million-dollar unit or an entry level, my message to you will be the same, it needs to be maintained.


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Jeri Geblin (@guest_264216)
1 day ago

Is Dicor 551LSW-1 Non-Sag Roof Lap Sealant better than Dicor 501LSW-1 Epdm Self-Leveling Lap Sealant? I’m buying a new Winnebago 33K. Should I seal w/Dicor right away?

Neal Davis (@guest_257021)
1 month ago

Thank you, Dustin!

Fred Deffinbaugh (@guest_256946)
1 month ago

What a bunch of crap ( why sealants fail). Is this a add or an AI generated article?

JCB2 (@guest_256716)
1 month ago

I’m an RV newby that just installed a Winegard Connect2 antenna dome to my Dutchmen trailer roof. The instruction warned to check with the roof manufacturer to specify what caulking to use. It’s a TPO roof made by Alpha and they guarantee only if Alpha caulking is used. There are different tubes for horizontal and vertical use. After cleaning the surface with mineral spirits, I used the horizontal and was well pleased with the ease of flow, adhesion and cohesion.

Kelly Hodges (@guest_256572)
1 month ago

A good friend of mine (only one I trust to be on roof) pressure washed my roof and I decided to use Flex seal. She only used a quarter gallon and it has held through 2 summers and this is the 2nd winter. We’ve had a few good rainstorms and TA DA no leaks!! It’s affordable and really works.

John the road again (@guest_256564)
1 month ago

“As the interior air pressure rises and hot and cold air attempt to force itself out of the gaps, it causes the tape to lift…”

Seriously? Unless there’s an RV out there somewhere built like a pressurized airliner, I can’t imagine any being air-tight enough for that to happen.

Cancelproof (@guest_256565)
1 month ago

You are 100% correct. No chance that the tape is peeling as a result of interior pressures not equalized with the exterior. Zero possibility. It’s peeling because it’s not sticking……

“Ink cartridge comparison”? Huh? Why not a box of cereal comparison? It runs out too and then you need more. A roof coating is not a consumable.

Last edited 1 month ago by Cancelproof
Cancelproof (@guest_256562)
1 month ago

Dustin, I think it would be worthwhile to inform readers that the “extended life” Dicor product is silicone, versus the standard acrylic by Dicor. The difference being that acrylic is water based and thus is not really waterproof without the reinforcing fabric and tape. Obviously, silicone is silicone and is waterproof but the draw back with silicone is nothing will adhere to it except for silicone. (Think silicone bakeware). Which means tapes or urethane or acrylics can’t be used for repairs once the roof is silicone. Only more silicone. This may explain better, for some, why tapes are peeling off some Dicor roofs like cookies from a silicone baking sheet.

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