Stopping Moisture & Mold Under An RV Mattress
Mold is a problem for all RVers, no matter what type of camper you have. It’s even worse for full-timers.
The mattress usually gets moldy first. This happens because moisture collects under it due to temperature differences between where you sleep and the space below. Many RVs have storage compartments under the bed, making this problem worse.
In our Class C motorhome, our bed sits over a large outside storage area. On cold nights, the mattress gets very cold from underneath.
Knowing these issues, we decided a mattress underlay was necessary. I’ve previously suggested the Den-Dry Mattress Underlay to prevent mold. Before, I used a dehumidifier and cans to air out our travel trailer mattress, but now that we live full-time in a small Class C, I wanted something easier.
Following my own advice, I installed the Den-Dry under our queen mattress. Here’s my review and installation tips.
RV Mattress Underlay Info
DRICORE DuraDri Mattress Underlay
Since writing this review, the Den-Dry mattress underlay has become permanently unavailable. However, I’ve found a very similar product with the same features.
Both the Den-Dry and the DuraDri are large mats with hard spun polyethylene on one side and a soft felt material on the other.
Their purpose is to lift your camper mattress to allow airflow underneath, which helps it dry quicker and prevents moisture from collecting in the first place.
It comes in three sizes: king, queen, and twin. Each size comes as one long piece, and if you get the king or queen size, you’ll need to cut the underlay in half to fit your specific mattress. For a full-size mattress, I recommend getting the queen size since the twin won’t be big enough.
The good news is that it’s really easy to cut the mattress underlay to size with regular scissors. So even if you accidentally get one that’s too big or you have a short queen in your camper, you can easily customize it to fit perfectly.
RV Mattress Underlay Review
In our RV, we have a standard queen-size full mattress from Ikea. It’s a solid foam mattress with no springs and it’s very heavy. I figured if this style of mattress underlay can support our thick Ikea foam mattress, it can handle just about anything.
it came rolled up and sealed in plastic packaging. The instructions are very straightforward and easy to follow.
The twin size doesn’t need to be cut, but larger sizes will need to be folded in half and cut to size. For the queen-size mattress in our camper, we cut the underlay in half.
I found the easiest way to do this was to roll out the entire underlay, fold it in half, and cut along the fold.
No measuring was required using this method and it was easy to cut with regular scissors.
If your RV has a short queen you will need to cut a little bit more off of each side after cutting it in half. Once I had it cut in half it was just a matter of getting it underneath the mattress in our RV.
According to the instructions, the hard spun polyethylene side goes down and the soft felt size goes against the mattress.
The mattress in our motorhome is in the corner, which made it a bit challenging to position the underlay just right. After our first attempt, we noticed the underlay had bunched up in one spot.
We tried to get it to lay flat a few times before realizing the best solution was to use a screw in each corner. This made it easy to position perfectly and actually helps hold the mattress in place better now.
We’ve been using it for about a month and I’ve checked several times to see if any moisture has collected underneath, especially after rain. So far, so good! The underlay has been doing its job well.
We used this same mattress in our old travel trailer without an underlay, and there’s a noticeable difference. Back then, we discovered moisture underneath a couple of times and had to prop it up on cans and run a dehumidifier all day to dry it out.
Now we don’t have to go through all that trouble, and I’m confident the underlay is preventing any mold from growing under our RV mattress. Since mold can ruin both the mattress and the wood in a camper, a mattress underlay is absolutely worth the investment.
6 Month Update
We’ve now been using the mattress underlay in our small Class C RV for 6 months, and I wanted to share an update on its performance.
For the past 4 months, we’ve been camping along the Texas coast on beaches and staying in beach town RV parks. The humidity here has been higher than anywhere we’ve ever camped before.
We’ve had to run the RV air conditioner frequently to try keeping the humidity level below 50% during the day, but at night levels can get as high as 80% inside our RV.
I recently inspected underneath our queen size mattress in the corner of the RV to check for mold growth. I’m happy to report that there’s no sign of mold anywhere—not even on the wood underneath the mattress underlay!
Everything has stayed dry, and it seems like the underlay has helped the air underneath the mattress dry out when we run the RV AC and our mini dehumidifier.
This climate has really put our RV to the test for mold prevention. With both of us working on the road and spending so much time in a small motorhome, humidity levels can get really high.
So far, running the RV AC has been the most effective way to get the humidity below 50%, and the mini dehumidifier helps maintain that. I believe without the mattress underlay, mold growth underneath the mattress could have quickly become a serious problem.
Hi Jenni,
How easy is it to install? I have a camper with the over the bunk bed. It is not easy to remove the queensize mattress and there is only about two feet clearance from the mattress to the ceiling.
Hi Alison,
I think it’s possible with a little creativity and help from another person, but being able to remove the mattress does make the installation a lot easier.
You could cut the underlay in half so it’s in two pieces to make it easier to work with. It’s easy to cut with scissors and it’s fine if it’s in a few pieces.