How to Control Moisture and Mold in an RV

How To Control Moisture and Mold in an RV. Pin this to save it for later!

How To Control Moisture and Mold in an RV. Pin this to save it for later!

Most homes have central air conditioning, insulation, weather seals on windows and doors, plus other measures in place that regulates condensation, temperature, and humidity. Condensation forms when water vapor in the air turns to a liquid that settles on cooler surfaces. Temperatures fluctuate depending on your region and the current season. Humidity is the measure of water vapor in the air, you can’t see it but you sure can feel it.

In your average home, moisture can cause mold to grow, wood to rot, and metals to corrode. You can see the struggle it is for sticks and bricks homeowners to fight off these issues, so, you can imagine the increased difficulty for those who live in mobile homes full-time. Whether you’re in an RV, skoolie, or van, these harmful elements are one of your worst enemies. Since our homes don’t have the internal climate control like a “normal” house does, we fall victim to this more often.

This means one of our highest priorities is to reduce moisture so as to avoid mold and mildew. If mold or mildew is already present, we must find the source and eradicate it. Not only are we going to talk about how to remove mold, but also how to hopefully prevent it from happening again.

Buyer Beware

By the time we finally got Luna, we were beyond ready to get started on our renovations. During our demolition, however, we discovered the unfortunate truth about our new (to us) RV: it was severely water damaged and had tons of mold.

Black mold infestation behind the bedroom wallpaper.

Black mold infestation behind the bedroom wallpaper.

We thought we had done a thorough inspection and the previous owner claimed there was absolutely no mold or water damage. By the time we tore out the damage and affected areas, Luna was a shell of an RV. We actually had an infestation of two different kinds of mold, black mold and Chocolate Tube Slime.

You can read more on the ways to check for water damage or mold before you fork over any cash in our post “What to Look for When Buying a Used RV”. We do, however, want to highlight a few useful gadgets we talked about in that article:

  • A Mold Test Kit where you can swab areas of the RV and test them right in the moment. It will tell you if mold or spores are present.

  • This Infrared Temperature Gauge would have helped us know if the cabinets that covered the worst of our water damage had “mold heat”.

  • A Moisture Meter, like the temperature gauge, would have saved us from not realizing how much moisture there was in the rig.

If the RV you fall in love with does have water damage and/or mold, don’t worry!  Now we’re giving you our tips on repairing water damage, getting rid of mold, and hopefully preventing this from ever happening again.

Black Mold |  CREDIT

Black Mold | CREDIT

Chocolate Tube Slime Mold |  CREDIT

Chocolate Tube Slime Mold | CREDIT

Catching the Culprit

The main causes of mold and mildew are condensation, humidity, lack of air-flow, and temperature fluctuations. If you can find the source of what faults in your rig are causing it to grow mold, you can almost always eliminate the problem. Inspecting your coach regularly for leaks or dampness is crucial. Monitoring the temperature and humidity levels is also vital. Keeping the air-flow in your rig regulated can eliminate a whole host of problems. So, how can you prevent these issues from forming?

RV mold removal
  • Check ceilings for leaks, especially in the corners. Open upper cabinets and check in there also.

  • Go low as well! Check behind furniture such as couches.

  • Make sure the seals around windows and doors are solid.

  • Be aware of any discoloration in paint, wallpaper, or window treatments. Bubbling or cracking paint or wallpaper is a sure sign of moisture intrusion.

  • Check your plumbing; around the toilet for leaking seals, faucets and shower heads for drips, and the pipes for leaks.

  • Improve air flow in your RV. Invest in fans, open windows, etc.

  • Avoid condensation. Wipe away any dampness. Check your temperature and humidity levels, find ways to adjust so condensation does not continue.

As long as you are regularly inspecting these problem areas, you should be able to stay on top of it and prevent any mold from forming. Finding the source of the leak and then making the necessary repairs is vital. Just keep in mind that any water, standing or dripping, can potentially cause mold, mildew, and water damage. If you do find moisture and mold is already forming, don’t stress! We are going to tell you a few ways to remove the mold and prevent it from coming back.

Making the Necessary Changes

Every leak is going to be different; you might need to re-caulk or reseal your windows, or the plumbing under your sink might need some tightening. Since there can be so many different sources of moisture, it is hard to know how to control the problem. As long as you are making regular repairs and staying on top of your known problem areas, you are doing the best you can. There are a few lifestyle and maintenance changes you can make in order to lessen the amount of moisture you may have in your RV.





  • Dehumidifiers

    This is a must; it is our number one recommendation. These pull moisture out of the air and significantly reduce condensation. They do draw a bit of energy and you have to empty a holding tank. Just make sure you have enough battery power and use the water from the holding tank to water your plants!

  • Cooking

    We cannot stress this enough: Cover pots when cooking. The vapor from your delicious meal is going to create a whole ton of moisture and condensation. Open a window and turn on an exhaust fan. Make sure the RV is ventilated well before you start cooking! Cook outdoor if or whenever possible.

  • Showering

    Shorten showers. Avoid steam by using cooler water. Open windows and vents. Use exhaust fans if you have on in your bathroom.

  • Laundry

    If you’re an air-dry person, make sure to keep your clothes line outside. You don’t want to put all of that dampness back into the air of your RV.

  • Ventilate

    Cracking a window, opening a vent, and using a fan or turning on you’re A.C. to improve airflow creates an escape for moisture and keeps the air moving.

  • Regulate Temperature

    If you’re A.C unit doesn’t already, invest in a thermometer and keep an eye on it. This might be obvious but if it is warm outside, keep it cooler in the RV and vice versus.

  • Monitor Humidity

    Ideally, the humidity in your RV should be between, but definitely below, 30-50%. We highly recommend a Hygrometer Thermometer and Humidity Monitor that detects the humidity levels. We already mentioned electronic dehumidifiers but we also love Damp Rid! These are calcium chloride crystals that dissolve as they absorb moisture from the environment, then you can refill the container once it’s done. We’ve also heard good things about charcoal briquettes being used to fight humidity if you’d rather go the DIY route.

  • Improve Insulation

    Using window treatments that are blackout will help insulate your RV better. You can also invest in DIY insulation kits for windows. Our RV is insulated with closed cell spray foam and we used an elastomeric roof coating to help regulate temperature.

While these changes don’t guarantee that you will never have moisture in your RV since some things just are out of your control, it will help significantly. If you do notice any condensation, just wipe it up. If you see moisture, mold, or water damage, acting fast is what will really save you.

Tackling the Damage

Before. Water damage under a leaky window.

Before. Water damage under a leaky window.

Having any form of water intrusion in your RV is progressive, it’s going to get worse over time. The outside of the RV can look fine but the damage can cause entire roof, floor, or wall to rot away. Above we mentioned regularly inspecting for leaks and taking care of those issues as they arise. If a leak has gone too long and caused damage to your RV, your only option is to repair the affected area. There is no magic product that will just make it go away, water damage must be replaced.

The best thing to do first is check with your insurance to see if they can cover some or all of the cost of your repair. After gathering that info, you can decide whether you want to do the repair yourself or hire out some help. We, of course, did everything ourselves when we found our water damage. We tore everything out that had been touched by water.

Look forward to a whole separate blog post on RV Insurance, our experience using it, and our recommendations later down the line. To find out more information on navigating the RV Insurance Industry, check out our friends over at Consumers Advocate. Their dedicated RV Insurance guide covers numerous factors when choosing a provider and we believe their research will make the decision-making process so much simpler!

After repairs.

After repairs.

You want to make sure to wear a mask or respirator while working in water damaged areas to avoid inhaling mold spores. Gloves , eye protection, and long pants/sleeves are also a good idea. As we tore out rotted wood, we sprayed surfaces down with a tea tree solution (1:1 ratio water to vinegar with 20 drops of pure tea tree essential oil in a spray bottle). Once we had removed all of the rotted wood, we did a treatment with the Concrobium Mold Control and a fogger. This product kills, eliminates, and prevents mold. After that is when we started to rebuild, replacing all of the affected areas with new healthy materials.

Not to sound redundant, but it is so important to find and fix all leaks before you move forward with rebuilding. Reseal your windows, repair your roof, use proper sealants, etc. Cleaning up mold right away as you notice it is crucial as it will save you from further, more expensive damage. On top of that, mold can adversely affect your health. Some species, such as black mold, are spore borne and contain mycotoxins. You can hire professionals to remove mold but there are also DIY methods that will save you some money

The water damage rotted away the subfloor.

The water damage rotted away the subfloor.

After repairing leaks, we replaced the subfloor.

After repairing leaks, we replaced the subfloor.

Exploring Your Options

Mold Gear

If your mold infestation is serious and extensive, you may be willing to do anything to get rid of it. In some cases, depending on the person, they will not be afraid to use whatever chemical will kill the mold and its spores. However, some people require natural removal methods because inhaling chemicals can be harmful or the individual has allergies and sensitivities. Depending on your personal preference, you may want to just take care of business or take the natural route.

The most important thing to remember, no matter what method you choose, is that mold has spores. Once you start agitating the spores, they become airborne. That means you can inhale them or it can spread to other parts of your rig. Be very mindful of this, wear protective gear and set up a contamination zone to contain any fallout. After treating your affected area with your preferred method, always allow 24-48 hours for drying.

Taking Care of Business

Most people think bleach is going to kill the mold they’re dealing with and aid in cleaning it up, however, this is a myth. Mold can burrow deep into porous surfaces, such as wood, and chlorine bleach is usually only designated for non-porous surfaces, therefore it just isn’t the answer in most cases. Bleach rapidly loses its effectiveness as the chlorine evaporates from it. Bleach is also considered toxic to humans after extended exposure.

If you would like to use bleach to stop mold from spreading fast or if you believe the mold is only on surface, so be it, but it is not our recommendation. The chlorine in bleach can actually feed mold and help it grow bigger and faster. Bleach will change the color of the mold but it will usually return in 3-4 months. We recommend borax if you want something strong like bleach.

Borax is a white powder that is available in most laundry aisles. For this method, you will mix one cup of borax with one gallon of warm water. You can transfer this mixture to a spray bottle and apply it to the affected area. You can use are rag or wire brush to scrub the mold away. You can repeat this process, wipe away any excess, but it is not necessary to rinse the borax away fully as it does help keep mold from returning.

Using a biocide product is another great option when using chemicals because they do not contain chlorine, ammonia, or VOCs. These will not only be more effective than bleach but will also penetrate porous surfaces. We highly recommend the Concrobium brand and their products. Like we mentioned before, we used their fogger system but they do make a spray for porous surfaces and an aerosol spray for fabrics.

Going the Natural Route

As someone with severe allergies and a ton of sensitivities to chemicals, Jacque prefers natural remedies before deferring to harsher methods. The natural methods are also more pet (or kid) friendly.  These methods can usually be made at home with DIY recipes. We also believe that using less chemicals is eco-friendlier and better for our personal health.

  • Essential oils: Tea tree oil is the most potent for eliminating mold, however, grapefruit seed extract, eucalyptus, and lavender oils can help support killing mold. You can add 10-20 drops of your oils to distilled water in a spray bottle.

  • Vinegar: You probably already have some in your kitchen. It has a lot of natural uses and is a handy cleaning product. You want 100% pure white distilled vinegar; you can use it and full strength or dilute it with water. Throw it in a spray bottle and apply it to your affected areas. You can add essential oils if the smell is too stinky for you.

  • Vodka: A spray bottle with one cup of distilled water and a cup of vodka, add essential oils to boost cleaning and cover the boozy smell. The alcohol in the vodka will kill the mold and its spores.

  • Hydrogen peroxide: It’s found in most medicine cabinets and can aid in eliminating your mold issues. Same as the other methods, you can put it in a spray bottle, use it straight or dilute it with water. Do not mix in essential oils due to the possibility of a chemical reaction.

  • Baking Soda: Add a few tablespoons of baking soda to an 8-ounce spray bottle full of water. Spray this directly over your affected areas and scrub away. Avoid adding essential oils as they may cause unreliable chemical reactions.

Putting an End to it, Once and for ALL

Once you’ve scrubbed away your mold issues, you want to spray the area one last time with your and let it air dry for 24-48 hours. Make sure the area is completely dry before moving anything back in. You should have fixed any leaks by this point and have started implementing some changes to decrease the moisture in your RV. Keep a watchful eye on the area that had mold, after a few months of it not reoccurring you should be able to rest easy knowing that you have successfully eliminated the mold. At this point our last recommendation is to use Killz Primer before painting to keep mold at bay.

If you guys try any of these methods or have some of your own, feel free to comment on this post or head over to our Instagram and let us know what works for you!