Best Caulk for Fiberglass RV

Are you looking for caulk to fix some cracks in your RV? Well, no worries anymore, we are here to help you with everything. We have made a guideline on finding the best caulk for your fiberglass RV, and all you have to do is follow-through.

Having an RV is a dream for a lot of us, and for those who love to travel or camp, the RV becomes the second home to them, just like how we get anxious every time there is simple damage to our house and try our best to find the perfect solution to fix it as soon as, we also do the same to our RV.

Best Caulk for Fiberglass RV

It is very common for your RV to face some damages that include cracks and leaks. As the RV stays outside most of the time exposed to the harsh weather, it is inevitable for them to get some damage. They have to withstand the hot temperature as well as the severe rain.

There is the various method you can follow to fix these problems. But the most common or easy is to use caulk or sealant. Like any other product, it is also hard to find the right caulk that will work the best without giving you any worries. As we understand your pain, we are here to help you with that.

We have gone ahead and done some extensive research to find the top five best products that are currently available. We have put them on a list with all the necessary information for you. So, keep reading ahead to know everything.

Top 5 Best Caulk for Fiberglass RV List

EternaBond RSW-4-50 RoofSeal Sealant Tape

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EternaBond RSW-4-50 RoofSeal Sealant Tape, White-4" x 50'

Last update was on: June 10, 2024 8:29 pm
$52.00 $64.99

The first product we are going to suggest you are the EternaBond RSW-4-50 RoofSeal Sealant Tape. If you are looking for something to work during the sunny days, this could be the best option you will get around in your hand.

This sealant tape is what you need during the hot weather. It is not only useful with its performance, but also the easy to the installation process is what makes it much more helpful for all the RV users. To get the best out of this product, you will need to prepare a little by selecting the affected areas and carefully put the tape on. It will be good to go after that.

 The tape is extremely durable to use. It has adhesive on one side with silicone lining. The lining will prevent the tape from getting stick to other surfaces before you apply it to the right part. Once you seal it to the right place, it is not going to come off quickly. The duration also depends a little on the weather condition, but as long as its sunny outside, you should never face any problem.

The measurement of the tape is about 4 inches wide and 50 inches long. But you can always cut it according to the required size you need. The application is totally mess-free and very easy to do so. You can cover up as much space you need, and it will stick to the part for more than 20 years. The best piece of this tape is that it is also very resistant to UV rays.


  • Perfect for hot weather
  • Easy to install
  • Has silicone lining to prevent sticking 
  • Durable
  • Can be cut in pieces
  • Cover-ups a big area


  • Some people said the tape is too sticky to work with

Dicor 501LSW-1 Epdm Self-Leveling Lap Sealant

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Dicor 501LSW-1 Epdm Self-Leveling Lap Sealant-10.3 Oz. Tube, White, 10.3 Fluid_Ounces (Packaging...

Last update was on: June 10, 2024 8:29 pm
$12.98 $17.99

The next product from our list is the Dicor 501LSW-1 Epdm Self-Leveling Lap Sealant. Dicor is a very well-known brand, and the best thing about this is that it is available everywhere, so you will not have to worry about buying it.

This Dicor sealant is by far the best to deal with water problems. It is watertight, which means no matter how much it is pouring outside, your seal will never cause any leak. The adhesiveness of this sealant will be able to hold onto anything in any condition. Whether it is aluminum, wood, vinyl, mortar, galvanized metal, or fiberglass, the adhesive sealant will fix anything you want. It comes in the color white that will go with your RV anytime.

This sealant is compatible with everything you need to fix in your RV. If it’s the ceiling, pipes, vents, or any crack, you can fix it with the help of this sealant. It can be used for any problem, which makes this one of the best one from our list. Because of the color white, you will find it easy to apply as well as it does not make things look odd either. The sealant is resistant to UV rays, so you will not have to worry about any UV rays getting on your way to mess with your work.


  • Comes in the color white
  • Very easy to apply
  • UV-resistant
  • Can be used on anything


  • A little messy if you do not apply appropriately

3M Marine Adhesive Sealant 5200

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3M Marine Adhesive Sealant 5200 – Permanent Bonding and Sealing for Boats...

& Free shipping
Last update was on: June 10, 2024 8:29 pm
$16.06 $18.81

The next product we have for you is the 3M Marine Adhesive Sealant 5200, which is another strong adhesive that you can use on your RV.

Just like the name of the product suggests, it is made to be a marine-grade seal, which means it is as good as to used by any professionals. The sealant is powerful and tough. Once you apply it on the cracked part, it will take the whole thing just like it was before. The application is very easy. You will not have to mix it with anything else. Once you apply with a weak, everything will be cured.

The bond of this sealant is so strong that it can withhold any condition like heavy rain, earthquakes, or storms. It is made out of tough polyurethane polymer that is well known for resistant to any weather, even saltwater. The bond is so strong that it will easily last for several years without any touchups. The last thing we like the best about this product is that it can swell or shrink very well, which is not noticed in lots of products.


  • A marine-grade seal performance
  • Can withstand any weather
  • Easy to apply
  • Great for permanent bonding
  • Swells or shrinks


  • Not useful to seal holes

Sashco 10016 10.5oz 10016 Big Stretch Caulk

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Sashco Big Stretch Acrylic Latex High Performance Caulking Sealant, 10.5 oz Cartridge

Last update was on: June 10, 2024 8:29 pm

The next product we have for you is the Sashco 10016 10.5oz 10016 Big Stretch Caulk. If you are highly concerned about rainy weather, then you should give a try to this Sashco caulk, which can withstand rainy days the best.

For making your RV roof watertight, this caulk will come in handy. This one is created especially for rooftop problems. But the best thing about this product is that you can even use it during the heavy rainy days without any issues. As the glue can easily sick to the wet condition, that is why a lot of users prefer it to use in their RVs.

Another great thing about this product is that it is versatile. It can be used in any type of roof; whether it is concrete, asphalt, or plastic, it will stick as good as anything else. The product is free of freezing. In the winter season, you can expect it to work just like before.

This sealant comes in transparent color. It is a significant advantage as you will not have to worry about your RV ceiling looking messy with dark or deep colors. The transparent color will make things look right, anyway. This long-lasting glue is also resistant to UV rays.


  • Easy to apply
  • Can be applied in wet condition
  • Versatile usage
  • Works fine during winter
  • UV ray resistant


  • Takes a little longer to dry

Geocel 28100V Pro Flex Crystal Clear RV Flexible Sealant

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Geocel 28100V Pro Flex Crystal Clear RV Flexible Sealant - 10 oz.

& Free shipping
Last update was on: June 10, 2024 8:29 pm

The final product from our list of the best caulk for fiberglass RV is the Geocel 28100V Pro Flex Crystal Clear RV Flexible Sealant for you.

This sealant is mainly designed for RV. It is a crystal-clear sealant that will work as one of the best products you can get your hands on. The best thing about this product is that once you apply it, you can easily expose the adhesive to any weather condition, and it will have no effect. The glue will never budge in any situation. So, you can stay without any worries.

The sealant has a wide range of spreading that will allow it to handle any hot temperature. You can apply it to any kind of material, and it will work fine on everything. Any moisture or dampness will not make any difference in how it works. It will cover up any crack, pickups as well as the UV rays. It is also resealable, which gives it more dimension of use.


  • Can be applied in any surface
  • Can handle any temperature
  • Resealable
  • UV-ray resistant


  • Can’t be applied in wet condition

Types of RV Caulks

Silicone caulk:

Silicone caulks are among the most popular for fiberglass RV roofs because they don’t require a primer before application and cure more quickly than other types of seals. These qualities make them especially appealing when you need an emergency repair.

Silicone Caulk

Acrylic caulk:

Acrylic caulks are popular for use on fiberglass RV roofs because they’re inexpensive, easy to apply and clean up with water. Acrylic caulk is also excellent for sealing the seams between separate panels of roofing material which can be exposed in a tear or hole.

Latex caulk:

Latex is a good choice for sealing seams in fiberglass RV roofs because it’s easy to apply and cleans up with water. Latex caulk also bonds well, so this type of sealant can cover large areas quickly. It is also the most common type of caulking because it cleans up easily with soap and water. It is best for people who are sensitive to smells or allergies in general.

Polyurethane caulk:

Polyurethane caulk is the best caulking for fiberglass RV. It provides excellent insulation, adhesion, and durability like no other. Polyurethanes are also great because they don’t shrink or expand with temperature changes as much as latex-based sealants do. The only downside to polyurethane caulk is that it cannot be painted over without first applying a primer coat of paint.

Adhesives caulk:

The adhesive caulks are often used in applications where the sealant is not exposed to water. These sealants require an application of caulk over a rubber-based glue, which then dries into a flexible and durable compound that can be painted or stained without any issues.

Fireproof caulk:

Fireproof caulks are often used in fire doors and other areas that need to be protected from flames or heat. These sealants have high-temperature resistance, making them perfect for use around furnaces, ovens, kitchens, etc.

Lysol caulk:

Lysol is the best caulking for fiberglass RV because it’s not only non-toxic but also has antibacterial properties designed to help keep your home clean and sanitary between deep cleaning sessions. In addition, Lysol’s provides excellent adhesion with less shrinkage than some of its competitors on this list, making them ideal for any application where you want an airtight fit over time.

Vinyl caulk:

Vinyl caulks are often used for things like windows and doors or anywhere else where water is present. Vinyl sealants have a softer consistency than silicone which makes them ideal for use in places that are susceptible to moisture because they can be painted over with any color of paint you want without damaging the caulk’s performance.

Benefits of RV Caulk

  • RVs can be exposed to the elements, and caulking is a way of preventing cracks from developing in the fiberglass.
  • Caulk also helps prevent water damage by creating an extra seal on windows or doors that could leak.
Benefits of RV Caulk
  • RV caulking prevents mold growth – it’s much easier to spot and remove any potential spores if they are found early when there’s not yet extensive damage done by them growing outwards into your living space.
  • The most important use for RV caulk is repairing leaks! It’s often possible to find small holes before they turn into major problems with water leaking inside the walls of your campervan. Smaller repairs may only take a tube or two of silicone adhesive sealant.
  • Caulking is a cost-effective way to maintain the integrity of your RV, and it’s something that should be carefully considered before making any repairs or replacements.

Tips for Using RV Caulks:

  • Make sure the surface is clean before you apply any sealant.
  • Put your finger over the nozzle when pouring out sealant so that it doesn’t dry up.
  • Make sure the sealant is being applied to a flat surface and that you’re using enough pressure for it to adhere properly.
  • Use your finger or a rag to smooth out any bumps in the caulk before allowing it to cure so that they don’t get caught on anything later when you drive around town with your rig!
  • When storing this type of product inside an RV, make sure you have someplace cool and dark where there won’t be too much heat and light exposure. It will last longer if left out of direct sunlight!

Features Must Have in RV Caulk 

There are so many options out there for RV caulk, but only a few of them have what it takes to be used on fiberglass. The following is a list of some of the features that should come in handy when selecting an appropriate type of RV caulk:

Flexibility: A flexible sealant can adapt to any imperfections found along the surface which may not be visible or known at first glance. This property eliminates air and water from entering unseen cracks, which could lead to major damage later on down the road.

Rubberized Finish: Caulk with this feature comes pre-textured with tiny bumps. This helps keep dirt and moisture from sticking inside crevices where they shouldn’t be.

High-Temperature Resistance: This property is important because most RV’s are exposed to extreme weather conditions, which can lead to problems for the caulking job if it isn’t built with this characteristic in mind.

Rust Resistant: If you’re using a metal caulk on your fiberglass, then make sure that the product has been designed and created from materials resistant to rusting or corrosion as well. Otherwise, the sealant will eventually start leaching out onto surfaces where it should not be seen at all!

UV-stabilized: This property is especially important in RVs because they are often exposed to the sun, weakening or destroying caulking. UV-stabilized caulk resists this problem and will be able to keep up with your needs for as long as you need it!

Note: These features may seem like common sense when looking into an appropriate type of material for RV fiberglass, but they’re also other factors involved in finding one that will work best without any complications further down the line.

Things to Consider Before Buying the Best Caulk for Fiberglass RV

The thing about RV is that you will need to take some extended care for it to work for a long time. As your RV is always exposed to the hard weather and other conditions, it is totally reasonable for it to get damaged over time.

Things to Consider Before Buying the Best Caulk for Fiberglass RV

But no matter what sorts of damage it is, you cannot just leave it as it is. If the damage is something that will cause leaking, you will have to fix it as soon as possible. One of the most faced things for RV owners is facing cracks or holes. In this case, the best solution is using caulk.

We have already suggested the top products that you can find to fix your RV. But before you decide on the product, we will like to mention a few things that will help you choose the best out of everything. They are-


The first thing you should focus on is the compatibility of the caulk. The caulk needs to be able to stick to where you want to. Sometimes the surface of the area you want to use the caulk will not be suitable for the type. That is why when you are going to buy, make sure it is appropriate.


There is not various type available. The two types you can see from our list are tape or liquid. Usually, the tapes are not good for wet surfaces, and for wet surfaces, the liquid is much more suitable. That is why you need to see what you actually need when you are buying.

Weather Resistant

The next thing you should focus on is the weather resistance of the product. There is some sealant available that can withstand any sorts of weather conditions. It is always better to buy one of those. But some of the products may not be suitable for hot weather or rainy days, so you need to figure out which one you prefer the best for your RV.

Frequently Asked Questions of The Best Caulk for Fiberglass RV

Do RV Caulks Work on Every Material?

No, RV caulks may not work on all materials. However, they are made to adhere best with fiberglass and vinyl, so if you have a mix of these two surfaces in your RV, then this is the product for you!

Do RV Caulks Work on Every Material

What is the Best Caulk for Fiberglass?

The best caulk to seal fiberglass RVs are silicone-based products because they provide a flexible expansion joint and can be used underwater. Silicone is also waterproof and provides a long-lasting sealant.

What Materials Can I Use a Caulk?

It depends on the products. Some of the caulk is usable in any sort of material where some will specify the particulars.€Z

How Long Should I Keep the Caulk for Work?

It also depends on the product itself. When there are a few products that will start working without hours, but some may take more than several hours.


That was all from our completed guide of the best caulk for fiberglass RV. We are well aware of the fact that it is quite a hard task to find the perfect and the most suitable things out there. That is why we tried our best to provide you with all the right options and information.

If you are still confused, we will ask you to go with the EternaBond RSW-4-50 RoofSeal Sealant Tape, which is by far stood out the best to use with its features and capability. Or, you can just choose any of the top options, the choice is yours!

Let’s Check Our Best Pick:

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EternaBond RSW-4-50 RoofSeal Sealant Tape, White-4" x 50'

Last update was on: June 10, 2024 8:29 pm
$52.00 $64.99

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