How to Prevent Moisture and Mold Growth Under an RV Mattress?

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Written by: Alex Savy
Read 9 minLast updated on July 7, 2022

RVs are a great way to add some adventure to your life and still feel almost like home. 

However, like everything, they aren’t perfect, and one of the biggest concerns for RVs is excess moisture.

Condensation under an RV mattress, inside your bed frame, and on other surfaces in your bedroom might lead to mold growth, which is not only unpleasant to see but can also cause health problems. 

So, be sure to read this article if you want to learn how to prevent moisture under your RV mattress and make the overall climate inside your vehicle more comfortable.

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Why Is There Mold on an RV Mattress?

Before we begin, let’s find out why there’s condensation under the RV mattress in the first place.

The answer is because RVs tend to cool down at night, which creates a temperature difference between your body that is lying on a mattress, and the surface on which the mattress resides.

Mattress can absorb up to 25% of the moisture that your body emits at night (1).

This temperature difference creates a dew point, so the moisture starts to condensate inside the mattress and goes down to the bottom. 

Since the majority of RV bed bases have a plywood sheet instead of slatted construction, the moisture has no space to escape and starts to accumulate.

And that’s how you get the moldy mattress.

Main Signs of Mold Infestation

Now, let’s talk about the main signs of mold growth inside your mattress. 

Spoiler: they are no different from the symptoms of mold on a regular mattress, and include:

  • Allergy-like symptoms. If you suddenly start waking up with puffy eyes or a runny nose, and these symptoms alleviate in a few hours after you get up, the problem might be in your mattress. 
  • Odors. Mold starts to grow pretty quickly because its spores are presented on most surfaces, and they only need the right environment. And when it happens, you might start feeling the musty odor even before the mold appears on the surface.
  • Visible spots. Finally, you may start noticing mold on the bottom of your mattress. Unfortunately, this means that your mattress is fully infected with mold and needs replacement.

Note that because of the flat surface, the insides of an RV bed are more prone to get moldy, so the best way of preventing that is by keeping an eye on your mattress and using some tips below.

RV Mold Prevention: 5 Tips to Keep Your Mattress Dry 

#1 Check the General Moisture Level in Your Van

The best way to prevent moisture under your RV mattress is to tweak the general moisture level in the van. You can do it by improving the ventilation system in your van, or by backing it up with a dehumidifier that will draw the excess moisture from the air.

It’s best to keep relative humidity within 30-50%, but you can tweak the numbers according to your preference and depending on the region. 

#2 Air Out the Bottom of Your RV Mattress

Another efficient way to keep moisture off the RV mattress is by airing it out regularly. Here’s how you can do it:

  • Remove all the bedding and leave the mattress exposed to the sunlight. Along with letting the moisture evaporate, this method also aids in eliminating dust mites, which are one of the most common allergens.
  • Lift one side of the mattress and place something under it. RVs are limited in space, so you might not succeed in removing the mattress off the bed frame completely. In this case, you can place something — a stool, water bottles, or cans — that can hold the mattress weight, and leave it like this for a couple of hours.

Make sure to check the mattress after airing it out: it should be dry to the touch, as well as the base of your bed. If one day isn’t enough for that, try switching sides of the mattress or using some other methods.

#3 Create an Insulation Layer

If your traveling route includes mostly regions with moderate humidity, you can prevent mold growth under your RV mattress by insulating the bed frame.

Insulation decreases the difference between the ambient temperature and the temperature on the surface of the plywood. Here are some easy and cheap ways to make it:

  • Cardboard. Cover your bed frame with 1-2 layers of cardboard boxes, and place the mattress on them. This is a quick fix for a relatively new mattress, which may last you for 1-2 months.
  • Mattress topper. You can purchase a foam mattress topper and place it below your mattress as a buffer layer. Note, though, that if the mattress topper becomes infested with mold, it can then transfer it to the mattress, so this is also a fix for 2-3 months.
  • Mattress underlay. These are usually made of hard plastic and have a convoluted structure. If you purchase this underlay, you can make sure that there’s always a layer of air between a mattress and the bed base, and the excess moisture will always have the space to escape.

#4 Rotate Your Mattress Regularly

Rotating your RV mattress, and flipping it from time to time, if your model allows for this, will help you keep moisture off the RV mattress and prolong its lifespan. 

Also, you can try using a fan, heater or RV wood stove and promote faster evaporation. First, rotate or flip your mattress. Then, place a fan near the damp area and direct the airflow, so it goes parallel to the surface of the mattress. Let it dry. If you’re using a heater, just place it 10-15 inches away from the mattress, so you won’t damage the foam, and let the warm air dry out any excess moisture.

#5 Craft a Hypervent Platform

Hypervent is a compound material typically used in gardening to create drainage systems. It’s made of non-woven plastic or synthetic fibers and is sold in square modules approximately 1x1 foot in packs of 4, 8, 12, or 16 pieces.

First, you have to determine the surface area of your RV mattress in feet to see how many pieces of the Hypervent you’ll need. We’ve done the math for you:

  • RV Bunk: 28” x 75” = 2100 = 14.58 sq.ft.;
  • Three-Quarter: 48” x 75” = 3600 = 25 sq.ft.;
  • RV Short Queen: 60” x 74” = 4440 = 30.84 sq.ft.;
  • RV Short King: 72″ X 75″ = 5400 = 37.5 sq.ft.;
  • RV California King: 72” x 84” = 6048 = 42 sq.ft.

After you purchased the material, trim it to fit your bed frame. We recommend that you trim it 1-2 inches narrower than your mattress width because the plastic fibers are really sharp. Then, connect the squares with something, such as string, fishing line, or something like that. Place the mattress on your platform. The easiest way to check the airflow is to make sure you see the whole construction underneath your mattress.

Hypervent is very durable and can last for years, so once you’ve made a platform, you’ll be protected from excess moisture and mold under your RV mattress.

And to make your RV experience even more comfortable, you can check the best RV mattresses here. We selected a bunch of best-sellers on the market and can ensure you that they are pretty resistant to mold and will serve you for years with proper care.


How to pick a mold-resistant RV mattress?

Check materials and construction. Mattresses that have coils inside typically are more resistant to moisture buildup and have better airflow. Natural materials, such as latex, are thought to be immune to mold as well, so we recommend that you purchase a latex mattress or a model with 1 or 2 latex layers.


Moldy RV mattresses are a pretty common issue. However, you can easily avoid it with these simple tips. Also, make sure you encase the mattress in a mattress protector, which will prevent mold spores from getting inside it and grow.

Have you ever had a moldy mattress? How did you deal with that? Share your answers below!


  1. Kay Wagers. (n.d.) What Are the Causes of Under Mattress Moisture? Retrieved

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