Friday, March 24, 2023


What you need to know about resealing your RV’s exterior

By Dustin Simpson, California RV Specialists
Manufacturers recommend that you check your RV’s roof and body sealants every 90 days.

Resealing and caulking your RV helps to protect your investment and creates a watertight seal to protect your unit from outdoor elements.

Applying caulking around trim and windows helps to ensure that no outside elements get inside through the window frame or other gaps.

When there is no caulk to prevent blockage, dirt and dust enter the RV more freely. If moisture from condensation, rain or snow, or by washing your unit gets into the RV, it can damage the structure or cause dangerous mold and mildew. Water and mildew stains can appear on the carpet and on the walls. However, in most cases, it doesn’t show up right away, causing unnoticed dry rot to occur.

Caulking around certain joints creates a watertight seal that prevents water from the outside from seeping into the cracks and crevices of your RV. If water gets in, it can cause a lot of damage that can be extremely costly to repair and even total your unit.

Applying caulking can also help prevent hot or cold air from moving outside. If you don’t caulk the borders around doors, windows, and walls, cool or hot air will escape. As a result, your RV’s heating and cooling usage will increase to make up for the loss, causing energy costs to go up if you’re living in the unit full time.

At California RV Specialists, we offer a free exterior evaluation and inspection of the body and roof sealants. Get your unit inspected even if you’re not in our area. Ask your local shops if they do free inspections.

Tools you’ll need to reseal your RV


  • Denatured alcohol – (Some states and towns do not sell this anymore at local hardware stores)
  • Acrysol – Available in a spray can – (see online store)
  • Cosmoline – (Not sold to the public)

*Use paper towels or old rags when cleaning.


  • Plastic scraper
  • Window glazing stick
  • No-drip caulking gun
  • Plastic razor blades


  • Dicor cap sealant
  • Boss sealant
  • Geocel sealants

…or any RV sealants/RV silicone. Do NOT use Home Depot or Lowe’s silicone. There are hundreds of types of silicone. Make sure you use the right ones. When manufacturers say don’t use silicone, it’s because most people think of standard silicone or water-based silicone. You MUST use silicone and sealants made for RVs.


  • Screws
  • Insert moldings screw cover
  • Gutter spouts
  • Clearance lights

Most manufacturers don’t seal everything, probably because it’s such a long process—especially when they advise you, as the owner, to check and seal as needed as part of maintenance.

Some manufacturers recommend every 30 days, others every 90 days. That number depends on use and weather conditions.

I really hope this information helps protect your investment.




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Bob M
10 months ago

I was surprised that Dicor is junk. My 2 year old Jayco travel trailer’s caulking looked great about 6 weeks ago when I washed the roof. I was on the roof yesterday and seen a couple areas bubbling. When I checked, it was soft like play dough. Don’t use silicone. It don’t hold up and won’t stick to it’s self. The military quit using silicone on their RV type equipment and now use a two part epoxy sealant called Proseal. Only down fall is it has to be painted.
If RV companies would design RV’s that didn’t need as much caulking and used a quality product. We wouldn’t have to worry as much about seals and caulking. I’d rather pay more for a better product.

Sailor Bill
10 months ago

Article lacks details. I’ve never used cosmoline on any of my RVs. I suspect this article is written by a robot.

Dustin Simpson
10 months ago
Reply to  Sailor Bill


Thanks for replying. There are so many differences in RVs, it would be hard to list everything. The most important thing is to remind others about the maintenance needed to protect their investment. I would say on average, at least once a week someone comes into my shop because they have water damage or they come in for a different reason and we’re letting them know about water damage they have.

I can’t tell you how many times I’ve been told, “no one ever told me this needed to be sealed.”

Anyways, no robot here. Just an RV repair shop owner trying to help others protect their investment.

Thank you
Dustin Simpson

10 months ago

This article is meant to advise! Advise you to check the seals in an earthquake zone! Try driving your home down a road and see how many leaks you’ll have! Rv’s take severe beatings from twisting, 150deg f to -50deg f surface temps and wind buffeting too!

Winnebago provides a list of every sealant used – it would be great to know exactly where each is used! However, factory advice is just an email or phone call away. Do due diligence in maintenance and sealants and you will extend the life and cost of operation of your Rv considerably. Happy trails to you all………

Dustin Simpson
10 months ago
Reply to  DW/ND

Thank you.

10 months ago

This article is lame. No details about where and why to use what.
Cosmoline? It’s a waxy substance that is used mostly to protect new metal parts. Not available to the public? Then why mention it?

10 months ago
Reply to  Thom

Exactly. Just an advertisement containing a few tidbits.

Dustin Simpson
10 months ago
Reply to  Thom


The Cosmoline may be available in other states for sale, Just not in California. The other two chemicals do the same thing to help clean and prep the surface for resealing.

10 months ago

“Manufacturers recommend that you check your RV’s roof and body sealants every 90 days.”

Then they should publish a guide with the exact procedure and exact name of sealants required for that model, make sure stores stock them, and they should build in ladders on all models.

Just a blurb in the paperwork, to absolve them of legal responsibility for bad building.

Dustin Simpson
10 months ago
Reply to  wanderer


Some manufacturers go the extra mile and some don’t. Just another reason why I make these reminders and tips.

As far as a ladders, I just posted some pictures and videos on my business site about that as well.

Some units are not walkable and some manufacturers don’t want older owner getting up on the roof for safety reasons.

Funny my wife doesn’t want me to get up on our house roof, but I’m up on RV roofs almost everyday. 😂

10 months ago

“Most manufacturers don’t seal everything, probably because it’s such a long process—especially when they advise you, as the owner, to check and seal as needed as part of maintenance.”

Huh? Is the author really saying that it’s a basic RV manufacturing procedure to intentionally bypass sealing all needed areas because it would cost them too much?

Even in today’s “slap it together and ship it” environment, I find it hard to believe that MOST manufacturers have a policy of not trying to caulk up their RV’s, where needed.

Dustin Simpson
10 months ago
Reply to  Spike

Thanks for sharing.

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