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One of the most common repairs an RV owner will face is preventing a leak from infiltrating into their camper. What type of caulk should be used on campers?

When you consider the long-term effects of mold or mildew growing inside the frame of your camper, what starts as a minor annoyance can quickly become a major complication. If mold grows unchecked, the result can be a camper that is not structurally sound because the moisture has rotted the inner structure, or even worse, create intense allergies and respiratory issues for your family. The last thing you want to do is to make your family sick or find out in the middle of a storm that your camper has sprung a leak because water is pouring in from an untreated area.

The type of caulk needed will vary depending on the project. You want to ensure that you use a flexible caulk that forms a good seal and offers protection from UV rays for exterior repairs. Indoor applications generally use water-soluble and paintable caulk for the best effects.

Regular maintenance of an RV must include an inspection of all seams and joints (inside and out) to ensure that no unwanted moisture finds its way into your vehicle. When you consider that regular caulking can also help increase the resale value of your unit, not to mention extending your camper's longevity, it is easy to see how essential regular maintenance can be.

This article will examine the caulk you should use to keep the water out and your family dry. You need to be familiar with different kinds of caulk to help you use the suitable compound for the proper repair.



Interior Vs. Exterior RV Caulk

Believe it or not, there is a difference between interior and exterior RV caulk.

Interior caulks are generally sealants that can be molded and used to fill up joints between fixtures and interior walls where there will not be a lot of movement or stress. The caulk used must be able to seal correctly and be airtight but soft enough to be paintable, should that be needed.

The exterior of your RV or camper gets exposed to all kinds of stresses during its lifetime. There are UV rays from sunlight exposure, winds, moisture from rain, and even movement caused by the bumps and imperfections of the road. (Every time your RV goes over a pothole or dip, the exterior caulk must be flexible enough to absorb the shock without losing its sealing properties).

The dual purpose of sealing joints and cracks dictates that most exterior caulks are made of different compounds. Some are self-leveling in allowing gravity to expand the caulk into joints and crevices, filling cracks you may not be able to see, and creating a tighter seal. Once dry, the caulk prevents water intrusion but can be flexible to handle the stresses your camper faces as it travels down the road. Self-leveling compounds are great for roof repairs.

Can You Use Residential Caulk for RVs?

Many residential caulks are marked for indoor use, meaning they are not flexible enough to use on rooftops and seal other porous surfaces. While most residential caulks are cheaper than RV caulks, don’t be fooled into thinking they are suitable substitutes for campers and RVs. The money you save will just be spent in a couple of months when you find the caulking must be repeated.

Types of Caulk

If you walk down the caulk aisle of your local hardware store, you will be overwhelmed by the sheer number of caulks available. Here are some of the basic types of caulk.

Latex Caulk

Latex caulk is sometimes called painter’s caulk because it is inexpensive. Generally, it creates an airtight seal between tile and shower fixtures and forms paintable seals on baseboards. Some manufacturers make outdoor latex caulks, but they do not handle outdoor elements well, like the constant UV rays your camper has to endure. A latex caulk will break down much faster than other kinds of caulk, so best to use this kind of caulk for interior needs.

Silicone Caulk

Silicone is a polymer that is sticky and much more flexible than latex. It is also resistant to UV rays but is non-paintable, rendering it useful in larger applications where painting is unnecessary. In addition, silicone is a sealant, not a glue, so use it on applications that need airtight applications.


The polyurethane compound produces a foaming sealant, used in insulating larger applications because it is highly resistant to temperature changes. Polyurethane is also a part of your refrigerator. The downside is that the foam turns yellow or brown when exposed to air over time, so it is not the best to use on your RV (if you care about resale value).


A Butyl-Rubber compound is ideal for outdoor projects because it binds quickly and effectively against sunlight and other external elements. It can be applied to a variety of surfaces which makes it ideal for use on campers and RVs. However, it can take a while to completely dry and is sometimes very difficult to work with. It requires paint thinner at cleanup, and while it is paintable, it is also very harmful if ingested or used in a non-ventilated area.

Is All Caulking Waterproof?

Not all caulking is waterproof, but most are. Be sure to check the label and the manufacturer's suggested uses to ensure that the caulking will meet the needs of the application you desire to fix.

Safest Caulk for RVs

By far, the most universal and ideal caulk to use for RV maintenance is

Geo-Cel Pro Flex Crystal Clear RV Flexible Sealant

Many RV enthusiasts have used this sealant with great success. It is flexible and fortified with UV protection so that it can be used in a variety of applications, both indoor and outdoor. Once dried, it is paintable as well.  This sealant is the Number one rated RV sealant on Amazon.

One of the best things about this caulk is that it can be used on top of itself, even when damp, so if you don’t get the bead right the first time, you can try again without worrying about messing things up. While it might be a tad more expensive than other brands, its versatility makes it worth spending a little extra.

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Ziollo Repair RV Silicone Caulking

If your definition of “safest” is the most eco-friendly, then this silicone-based caulk should be your choice. The company is committed to making an environmentally sound caulk, so you do not have to worry about breathing in toxic fumes. The application can be used indoors and outdoors - however, it should be noted that it is not paintable and only comes in black. It has terrific reviews and has received a 4.7 rating on Amazon.

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Most Durable RV Caulk

You want a caulk that will last so that you do not have to reperform this same project. For roof repairs, our recommendation is

Dicor Self-Leveling Lap Sealant

The best part of this compound is it is self-leveling which means that gravity helps level the caulk out without you having to worry about using a tool or your fingers to create a smooth, soft edge. But it lasts a long time, and while you might still need to inspect your roof for additional signs of damage, chances are it won’t be this joint or crevice.

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Least Expensive RV Caulk

If you want to save money and your job is not too large, we recommend you use the following.

Gorilla White Caulk & Seal, 10oz. 100% Waterproof Industrial Sealant

From the makers of Gorilla Glue, this sealant is waterproof and easy to apply. While we wouldn't suggest it for larger projects, it can work for more minor uses inside and outside your camper. It also has a clear version if you prefer that color over white.

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How to Choose a Caulk Type for Your RV

Depending on your repair, the correct caulking can make a difference. Inspect your trailer for cracks, crevices, and gaps. Consult with your RV body shop to get their recommendations and find out what they are using. Read the instructions and directions to know the limitations and applications of each sealant/caulking. Then prepare with the proper protective equipment and get started. A project never started is a project never finished.