In the midst of Alaska winters, I dreamed of warmed weather. I counted down the days to an RV life where I wouldn’t be in cold, dark, snow-and-ice winters again. In an ironic twist, the first three months of my RV life included freezing temperatures, snow and ice. At least I managed to avoid the extreme limited daylight hours by being south of Alaska. One of the results of cold weather, I learned the hard way, is condensation. And one of the results of condensation is mold. I tell you this story as a cautionary tale in hopes you don’t find yourself in a similar situation.

Let’s file this under the category of Things I Wish I Had Known. I never read it on the blogs I followed leading up to my RV life. I never saw RV vloggers address it. And it wasn’t mentioned in my trailer’s orientation.

I wish I had known.

Here’s What Happened

I picked up my trailer on October 24, 2017. Because I’d spent the day at the Oliver office for my orientation (link?), I had less than thirty minutes of light once I was set up at the campground. So there was only time to grab what I needed from the van. Purse, computer, Kitty’s litter box, a pile of blankets, pillows, pajamas and some food to get us through the first night

I have two thick plush blankets from my king-size bed in my sticks-and-bricks. I folded one to fit the bunk-sized mattress. The other, I’d pull over me. It wasn’t a great setup but it would work until I could find the sheets I’d purchased before I left Alaska.

The bottom of the mattress dotted with mold.

It was chilly at night in Tennessee. I love those plush soft cozy blankets so much I ended up not changing my set up until I arrived and settled in Washington State a few weeks later. Plus it took me that long to find the memory foam, mattress pad and sheets in “storage.” AKA the van. AKA the tow vehicle.

When I picked up the corner of the mattress to put the mattress pad, I was shocked. The bottom of my beautiful brand new mattress was dotted with black spots. I knew instantly what I was seeing. Mold. I was disgusted and horrified.

What I didn’t know was how the heck it had happened.

What I Learned

Mold grows where there is damp or decaying organic matter. Sealed areas with moisture (even a small amount) are ripe for mold growth. A friend in construction informed me that as soon as a structure gets a 5-star energy rating, workers go around and drill holes in the structure. Many 5-star structures are too energy efficient. They are so sealed, so energy efficient, that they become mold factories. He said my molded fiberglass trailer was the equivalent to a 5-star house.

Clean Up

I took his advice and did the same thing he does when he finds it in a house. I got out the bleach. He advised me to put it in a spray bottle diluted with water, lightly spray the mattress and let it dry.

The tiny space heater doing a big job, drying the bottom of the bleach-sprayed mattress.

Never one to go half way, and being thoroughly disgusted by what I saw, I took his advice to the extreme. First I took a cotton ball dipped in bleach and touched the worst of the black spots. (It was worse in one area but it took me weeks to figure out why.) Next I filled my spray bottle with bleach. No dilution here. I sprayed the bottom and the edges of the mattress.

Drying it became the biggest challenge. It would’ve been easier in warmer a temperature but I was already fighting a cold trailer. (In the near future I’m going to write a post about quote-unquote four-season trailers). In a small trailer, setting up the mattress is not easy. But I managed to finagle the thing into an upright position. Then I turned my tiny space heater on high and waited.

Slowly it dried and slowly many of the black dots disappeared.

Not all of them. But I was kind of done with it on that day after all the hours spent on the project. I decided eliminating the mold would likely be a multiple treatment job.

I used white vinegar and a paper towel to remove mold from the fiberglass. There were only a few dots of mold on the fiberglass. Nothing compared to the organic cotton mattress. But still, I learned it also can grow on fiberglass.

Round Two

After I got the bed back together—mostly free of mold—I tasked myself with constructing a prevention plan. Even though my cold weather situation wasn’t going to change any time soon, I hoped there were proactive steps I could take to prevent future mold growth.

The plan:

  • Keep a window cracked at all times. I figured it was the equivalent of drilling a hole. It wasn’t that fun during the really cold temperatures, but I did it anyway.
  • Turn on the overhead fan on the setting to suck air out every time I used the cooktop stove.
  • Lay a sheet (yep, king-sized folded over multiple times) on the fiberglass below my mattress thinking it might absorb moisture before it got into the mattress.
  • Turn 180 degrees for sleep. I had started with my head at the end of the trailer, next to the nightstand. (You might remember when I introduced the trailer that one of my complaints was Oliver put the additional reading lights I’d purchased at the foot of the bed where they don’t do much good for extra light to read by.) With my head down by the nightstand, air was more stagnant because I was surrounded on three sides. By changing positions and moving my head to where my feet were, I opened up one side. And as an added bonus, I could now use the reading light.

Then the Really Cold Temperatures Hit

And here’s where things got interesting.

A cold frosty day before the snow and ice arrived.

During my two weeks in Tennessee and the first month in Walla Walla, the temperatures were in the 40s and 50s during the day and down to 30s and 40s at night.

As an Alaskan, I defined a hot summer day as anything over 65 degrees. So, overall, I found my first six weeks quite pleasant. Yes, it was cold if the dog wanted to go out in the middle of the night or when I walked to the showers in the early morning hours. But after the sun came up and added 10 or 15 degrees to the day, I was comfortable.

A week before Christmas, the temperatures dipped. Actually, they dove. A few days before Christmas, Walla Walla got a dump of snow and a few days after, there was a fairly severe ice storm. For three weeks, daytime temperatures were in the mid and high 20s. Nighttime temperatures were in the teens. The single coldest overnight was 12 degrees. That night, my water line froze.

In other words: day and night, it was cold. The space heater ran constantly inside the trailer and still it never truly felt warm. I didn’t run the furnace as much as I could have but I didn’t want to deal with a propane refill in the middle of all that cold. I saved the propane for cooking and showering. Showering, I say, because when it was that cold and slippery outside I no longer wanted to walk to the showers.

It can be hard to see because the surface is reflective but look close and you’ll see the constant stream of water I was dealing with.

Then I noticed something. Streams of water running down the trailer walls. Condensation was no longer this invisible demon I was battling. I could see the enemy as it crawled down the wall right to the mattress and seat cushions.

If there was a way to prevent the stream, I certainly didn’t know it. And since my proactive approach wasn’t working, I went into reactive mode. I stuffed towels—bath-size towels—where the stream came into contact with the mattress and cushions.

The water was such that I had to replace the towels every 24 – 48 hours. I had a set of towels hanging around the rig drying, preparing to replace the towels that were absorbing water.

Then I realized something interesting. And, I’m sure, something telling. Though I still don’t know what it’s telling me.

The tan towel is catching the stream of water. The silver is the belly band sealing the top and bottom halves of the fiberglass trailer. But the water came from the bottom of the window, a few inches above the belly band.

Exactly one stream ran down from each window. And, in the exact same place. Six inches from the edge of the window, on the side that opened (the side where the screen is for fresh air), was where water dripped. There must be something about the construction of the windows that “gathers” the moisture to that location.

If anyone has any insight into this, I would love to hear it. I’m at a complete loss.

When I left Walla Walla and made my way to Northern California where temperatures were once again more reasonable, the stream stopped. I did another bleach treatment to the mattress. And, I suspect, it is going to need another one in order to get rid of it all. It’s hard to get it all at once without completely drowning the mattress in bleach.


It sucks that I’ll never have the beautiful perfect mattress that I left the Oliver factory with. Because of the one rounded corner and the size, the mattress is custom-made. And pricey. I paid $800 for it, almost the same price I paid for the king-size pillow-top mattress I used in my sticks-and-bricks.

My cushions are dark gray, too dark to see if I have the telltale sign of mold. Black dots. I haven’t sprayed bleach on those as I fear the treatment will discolor the cushions. I don’t care about the color change of the mattress because it is covered by sheets and blankets. But the cushions are part of the decor of the rig. I did space heater them dry. And crossed my fingers.

As I write this, I am in much warmer temperatures—50s, 60s and low 70s. Nights still are in the 30s and 40s. But no sign of the scary rivers created during the really cold days.

Maybe in my future? Maybe not.

It was never in my RV plans to be in cold weather. I simply had enough of it living in Alaska for 24 years. The experience I’ve had with growing mold has me even more committed to staying out of the cold.

Still, it makes me a little sad. One of the reasons I bought the four-season trailer was I didn’t want to limit my travels. I knew that after a few years of nothing but sun, I might be ready to finally learn to snow shoe or cross country ski. But my recent experience certainly has given me pause. I will think twice before heading into weather that falls below 30 degrees.

If you have any words of wisdom, I would be grateful. It is not in my budget to frequently replace an $800 mattress. Nor should it have to be.