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Best RV Caulks and Sealants For Exteriors: Top Picks and Reviews

Need to find the best RV caulk and sealant for your RV exterior? We've got you covered.

When maintaining your RV, it’s crucial to keep up with the monthly and yearly maintenance and to caulk your RV to prevent leaks. In this article I’ll chat about the best RV caulk for you exterior.

After our rig started showing signs of a leak in the back, we remembered that it had been over a year since we’d done any RV exterior caulking. It works great when you remember to do it often and is horrible when you forget.

After noticing the leak, we took our rig to the local RV repair place thinking that there was some hole somewhere. We were happy to find out that it was just do to the broken seal in the caulk, but also a little upset with ourselves for letting it go so long.

To make sure that doesn’t happen to you, just get the best caulk for RV exterior and make sure to add the task or a reminder to your calendar so you know when it’s time to do it.

Whether you’ve noticed a leak starting and want to fix it or if you’re trying to keep your RV in top shape, maintainting it using caulk is one of the simplest things you can you.

So do you need a special kind of RV caulk and is buying the RV specific stuff really worth the price or can you can away with the regular 30+ year latex caulk?

Best RV Caulk Comparison Table

IMAGEPRODUCT
TOP PICK!1. Geocel 28127V Pro Flex Bright White RV Flexible Sealan
  • Suited more for roof
  • Full manufacturer warranty
Check Latest Price
2. EternaBond RSW-4-50 RoofSeal Sealant Tape
  • Uses MicroSealant Technology
  • Simple installation
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3. Dicor 502-LSW Self-Leveling Lap Sealant
  • Great overall product
  • UV stabilized
  • Compatible with EPDM
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Best RV Caulks and Sealants

Geocel 28100V Pro Flex Crystal Clear RV Flexible Sealant

The Geocel 28100V is composed of multiple polymers and offers excellent “stick” to most any substance on your RV. It’s not water-based, so it will dry in damp conditions, though you’ll want to make sure the area you’re sealing is as clean and dry as possible.

This will not clean up with soap and water and is formulated to stick to any surface, including your skin. If you cut too large a hole in the tube or apply it inconsistently, it will be very hard to get a smooth, clean line of caulk.

Wear gloves, use a bit of soapy water to dip your fingers in to get a smooth line, and avoid applying this product in a thick bead. Additionally, keep a lint-free rag close by for globs.

ToughGrade Self-Leveling RV Lap Sealant

If you need to touch up the seams on the roof your RV, ToughGrade sealant is a great choice. This is a self-leveling caulk that will stick to any surface that’s clean, so if you need to go over old sealant just for seasonal protection, this is a great choice.

Make sure to follow all application instructions and wear gloves; keep mineral spirits around for final cleanup.

This is a self-leveling product, so it give a great seal on your roof but can’t be used on your windows. It won’t form a consistent seal and will sag down vertical seams before it dries.

Additionally, take care to really manage the amount of product you’re putting on the seam so it stays consistent. Too much caulk on a bead will quickly get messy.

EternaBond RSW-4-50 RoofSeal Sealant Tape

The name doesn’t lie; EternaBond RoofSeal tape will stick forever! It’s available in a variety of widths and fairly simple to install on a long run. Apply this tape to a properly cleaned roof early in the day to avoid air bubbles and dust settling. Best of all, you can use what you need and put it away for the next installation and it won’t dry out as caulk can.

It’s possible to get air bubbles under this, which can weaken the tape over time. You will need to work in very short sections even with a long piece of tape to get it properly smoothed.

Do not skip any cleaning step for a proper seal. Finally, be aware that this tape is stuck once it’s applied and can stick to itself if you get folds in your application. Avoid interruptions for the best quality job. Curves can be a bit of a challenge; be careful with your cuts and your layout.

Dicor 501LSW-1 Lap Sealant

A Dicor roof system is a multi-step process to a watertight seal, and this Dicor product is the third. This lap sealant is used to create a second layer of protection and sticks well to properly cleaned aluminum, vinyl, and fiberglass.

Your RV roof seal is secure with this product on top. Many RVers use this product as a standalone sealant and have had excellent results.

There is some confusion on self-leveling vs. non-self-leveling. Dicor sells multiple products; the #1 lap sealant is self-leveling and will work for roofs. Don’t use any self-leveling products on vertical seams.

By design, they won’t last. This can be used over old sealants, but you will lose cling if the existing sealant is cracking or breaking away from the surface. Remember that this is a secondary sealing product. If you need something thicker or to seal a bigger opening, look for a non-self-leveling product.

Sashco Clear Lexel Adhesive Caulk

While this product is designed for home use, Sashco Clear Lexel is an impressive tool and could be used on vertical RV seams. It dries clear but can be painted after 24 hours. It offers terrific flex and excellent UV resistance.

This product is extremely sticky and skins over quickly. Try to use it early in the day so you have as little air movement as possible. Keep water close by so you can maintain a clean bead and be ready to practice a bit at the start.

It does take a while to cure completely and may pick up debris and dust as it dries. Try to protect your new caulk with a tarp awning or windbreak to keep the dust out.

Alpha Systems Self-Leveling RV Roof Sealant

If you have a rubber roof on your RV, this self-leveling sealant is a great product to have in your toolkit. Alpha Systems roofing products are extremely flexible and ideal for areas with high UV exposure.

It’s an excellent sealant on flat surfaces and will reflect sunlight for a long lasting seal.

This is not a great product for fiberglass or metal. If all you’re working on is your rubber roof, keep a tube or two close by. However, if you need to seal around solar panel brackets, your metal AC housing, or anything that isn’t TPO (Thermoplastic Polyolefin).

Don’t use this caulk for those applications. Also, let this product cure completely before using any other sealant in other areas.

M Marine Adhesive Sealant

Like a lot of marine products, the M Marine sealant is very tolerant of moisture, salt exposure, swelling, and shocks. If you and your RV are going to be spending a lot of time on the seashore, this is a great choice. It bonds to multiple materials once properly prepped, including plastic, fiberglass, and metal.

Like a lot of marine products, this sealant isn’t cheap. It will take some time to fully cure and goes on very sticky. Invest in gloves that fit well and work with a small bead for best results.

This sealant is tinted tan, which may not be the same as the tan of your RV. If you’re going around windows, do a patch test to make sure the color will work on your rig. Once you’re ready to start, try to use the whole tube; caulk can be hard to store.

Sashco 10016 Big Stretch Caulk

The Sashco Big Stretch performs as promised and is designed for use in stick and brick houses. It is paintable and cures quickly. If you have cabinetry in your RV that tends to show gaps after a rough road, this could be a permanent fix for these cosmetic problems.

While this may be a great sealant on anything that needs to flex, it’s not recommended for anything that will suffer from moisture exposure. If you decide to use it in your RV, consider putting a moisture proof sealant over it.

Make sure to clean the surface as required prior to applying and work fast; this skins up quickly. Gloves and soapy water are a great accessory when applying this product.

Gray Tremco Vulkem 116 Polyurethane Sealant

The Tremco Vulkem line is designed to bond to many different surfaces, from porous to smooth, and will tolerate being underwater with the right prep and primer.

This is not a self-leveling product, so if you need to work on window gaps or any breaks in your RV walls, this product will fill and flex as you move down the road. Airstream-ers love this sealant!

This sealant is truly better living through chemistry. Make absolutely sure that you prep the surface as instructed and use fans to move air through your RV, even if you’re applying this to the outside.

The curing time may vary; if you don’t have to be in the RV, let it air out for an additional 24 hours just to be safe. This product will outgas and is restricted in certain countries.

3M Marine Adhesive Sealant

RV caulking can be expensive. If you’ve ever tried to save a tube, you know how frustrating it can be to find that there are several dollars worth of sealant frozen in the bottom of the tube because the top is dried out and plugged up. The 3M company has reduced this headache by offering their sealant in small, disposable tubes.

Pay attention to the color; this is not paintable. This marine sealant is very popular with divers, so if you’re sealing anything plastic, you’ll be happy with the “stick” of this product.

This marine sealant is designed to work well against water pressure. If you need something to protect your RV from sun damage, make sure you don’t get the black sealant. Study the UV tolerance of any marine sealant to reduce the risk of putting the wrong product on your roof and windows.

Why is RV exterior caulking necessary?


When you’re driving down the road and going over bumps with your RV, it tends to move and twist and give in the right spots. All this moving causes the seals to break down and crack.

Since the seams crack over time, you want to setup a scheduled maintenance plan to reseal all the trim, windows, doors and anywhere else where water can get in.


Your RV’s roof also has seals that you’ll need to reseal, but you’ll want to use a different product to seal this area and we’ll cover that below.

Will typical Silicone caulk work ok?

So many people think that you can just add any type of sealant and it will work. But this is not correct. The issue with silicone is that it doesn’t hold the seal when the RV moves and twists so it’s like you’re not even adding a sealant to protect your RV.

The other issue with silicone is that moisture can easily get underneath where the silicone breaks from the RV flexing. When this happens, you have a very diffult time finding the leak.

Should you recaulk or remove old caulk before applying?

When you’re caulking, can you just apply over the old caulk or do you need to remove all the old stuff before reapplying. Many people ask this because it’s not the most enjoyable thing to do to cover your whole RV seals and so they want a shortcut.


If you purchased a used RV and someone sealed the windows and doors with silicone, then you’ll definitely need to remove all traces of the old caulk because nothing will adhere to it, not even old silicone.


To prevent from scratching or removing the paint on your RV, you can use a plastic razor scraper

How long does it take to recaulk an RV?



Now that you know all the details about recaulking, which one should you use? Some people try to get by with the cheapest stuff out there. But why pay all this money for your RV just to scrimp on the sealant?

Many people suggest the RV ProFlex. When you go to reseal your roof, then use the Dicor Lap Sealant. This is a self leveling sealant that will work on most roofs. You can also use Eternabond for the roof sealing areas. This is a tape that you can apply over older sealant on the roof and it will bond with it and provide a good seal.


You can watch this video that will show you how to properly seal your windows and doors for your RV

Conclusion

Now that you’ve found and applied the best caulk for RV exterior, your rig should be good to go until the next maintenance time.

Resources:

RV Expeditioners

CypressTrail RV

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