Condensation & Mold in 337 RLS Slide-Out – Need Advice!

[rudy558]

Even if you only have advice on one part of this, we'd really appreciate it! No need to address everything—any insight is helpful.

We’ve been struggling with persistent condensation and airflow issues in our 337 RLS Reflection and could really use some advice from those who have tackled similar problems.

Temperature Conditions:

• The worst condensation happens during extreme cold (below 20°F with wind chill). We believe the temperature differential is a key factor.

Our Setup:

• RV Model: 337 RLS Reflection 5th Wheel
  
  
• Problem Areas:
  • Hitch-Side Cold Draft – Cold air enters on the hitch side of the bed, leading to condensation between the bed and the slide-out wall.
    
    
  • Moisture Under the Bed & Dog’s Sleeping Area – Condensation forms along the floor under our dog's bed in the closet alcove, leading to mold against the step-up.

---

What We Need Advice On:


1. Checking for Mold and Removing Carpet

• What We’re Planning to Do & Need Advice On:
  • Remove the carpet between the outer wall of the slide-out and the bed support to inspect the wood underneath.
    
    
  • Any tips for safely doing this in a slide-out?

• What We Are Encountering:
  • Moisture and mold on the wall and floor of the hitch side of the bedroom slide out between the bed and the slide out wall.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.
    
    
  • Moved one of the dehumidifiers into the slide-out corner.
    
    
  • Attached a small fan to the legs of the homemade night stand (has space around the support for airflow and a damp rid container) between the bed and the slide out wall

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • The homemade nightstand that has been in that corner for a year has space around the support for airflow and we had a damp rid container in there
    
    
  • There is a dehumidifier in the room

• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

2. Pulling Up Trim in the Closet Step Area

• What We’re Planning to Do & Need Advice On:
  • Remove the trim to inspect for mold and moisture.
    
    
  • Any advice on removing this without damaging the structure?

• What We Are Encountering:
  • We found moisture buildup between the bottom of our dog’s bed and the floor as well as mold on the step in the closet alcove
    
    
  • We suspect more mold behind the trim where the closet step meets the floor.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.

• What We Are Now Doing to Prevent Future Issues:
  • We have now placed her bed on a raised dog bed frame to maximize airflow even more than that provided by Dricore.
    
    
  • Attached a small fan to the clothing rack in the closet to increase airflow further.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Used Dricore Mattress Underlay between our dog’s bed and the floor and between the back of her bed and the closet step-up - moisture occurred where it was anyway
    
    
  • Removed the closet doors (her bed wouldn’t fit otherwise).

• Notable: We didn’t find moisture in the rest of the closet—only between the dog bed and the floor/step.
  
  
• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

3. Improving Bed Airflow & Lowering Bed Height

• What We’re Planning to Do & Need Advice On:
  • We are considering replacing the solid wooden support with a steel support that has lots of airflow and is shorter (bed frame)
    
    
  • How might replacing the bed support affect the slide-out’s function?
    • Any concerns about wiring, slide-out mechanisms, or movement?

• What We Are Encountering:
  • We are not having mold between our bed and the bed support
    
    
  • Our bed is just too high, we have to be careful not to hit our heads on the slide out ceiling
    
    
  • Because of this and the general issue of airflow in other parts of the bedroom, we are thinking of changing things up.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Installed a mattress underlay under the bed Dricore (in place for about a year).
    
    
  • Painted the wood bed support with antifungal paint (in place for about a year).
    
    
  • No issues with moisture/mold under the bed, only between the bed support and the outer slide-out wall.

---

4. General Air Flow and Moisture Situation

• Bedroom Door Removed – Since it’s just us, we keep the bedroom door off to allow maximum airflow
  
  
• Dehumidifiers – One in the bedroom, one in the living room, we had one in the bathroom but have moved it to between the bed and slide out for now.
  
  
• Ventilation
  • Kitchen vent is always used when cooking.
    
    
  • Showering is avoided in the RV whenever possible (alternative showering options used).
    
    
  • When we do shower, we open the vent and run the fan to prevent condensation.

---

5. Additional Thoughts & Photos

• We’ll include photos of what we’re dealing with. It’ll take a second because I’m going to post this first.
  
  
• Any suggestions on any section would be greatly appreciated!
  
  
• We’ll also update this thread with what we find and what ends up working (or not working) to help future forum members dealing with similar issues.

Edited because half the text ended up bolded for some reason.

 

[rudy558]

Ignore the orange-y color on the picture of the space between the bed and the slide out wall, it is from me dropping a flavored melatonin pill. The pill got wet and left some orange smudges. The dark patches concern me though.

The picture of the space between the bed and slide out wall with the dehumidifier is after we discovered condensation again and is showing the supports of the night stand.

The picture of the raised dog bed is showing the new solution for airflow that we've implemented.

 

[WhittleBurner]

Even if you only have advice on one part of this, we'd really appreciate it! No need to address everything—any insight is helpful.

• Problem Areas:
  • Hitch-Side Cold Draft – Cold air enters on the hitch side of the bed, leading to condensation between the bed and the slide-out wall. If youre parked for long term seal off the hitch even if its taping plastic and insulation around it
    
    
  • Moisture Under the Bed & Dog’s Sleeping Area – Condensation forms along the floor under our dog's bed in the closet alcove, leading to mold against the step-up.

---

What We Need Advice On:


1. Checking for Mold and Removing Carpet

• What We’re Planning to Do & Need Advice On:
  • Remove the carpet between the outer wall of the slide-out and the bed support to inspect the wood underneath

Get a few staple removers and knee pads, the carpet is stapled and runs under the lower trim. It should come out from under there without much difficullty once all the staples are removed. Don't be suprised if there are hundreds of staples!

• • Any tips for safely doing this in a slide-out? Be patient they love using staples..might be about a 3rd of your weight lol

• What We Are Encountering:
  • Moisture and mold on the wall and floor of the hitch side of the bedroom slide out between the bed and the slide out wall.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.
    
    
  • Moved one of the dehumidifiers into the slide-out corner.
    
    
  • Attached a small fan to the legs of the homemade night stand (has space around the support for airflow and a damp rid container) between the bed and the slide out wall

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • The homemade nightstand that has been in that corner for a year has space around the support for airflow and we had a damp rid container in there.. little muffin fans might help with airflow
  • There is a dehumidifier in the room

• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

• What We Are Encountering:
  • We found moisture buildup between the bottom of our dog’s bed and the floor as well as mold on the step in the closet alcove Check the outside of the slide for opennings in the seal and exterior trim along the floor even a tiny pin hole can invite in mpoisture
    
    
  • We suspect more mold behind the trim where the closet step meets the floor

• What We Are Now Doing to Prevent Future Issues:
  • We have now placed her bed on a raised dog bed frame to maximize airflow even more than that provided by Dricore.
    
    
  • Attached a small fan to the clothing rack in the closet to increase airflow further.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Used Dricore Mattress Underlay between our dog’s bed and the floor and between the back of her bed and the closet step-up - moisture occurred where it was anyway
    
    
  • Removed the closet doors (her bed wouldn’t fit otherwise).

• Notable: We didn’t find moisture in the rest of the closet—only between the dog bed and the floor/step. The dog sleeps sweaty and it's wicking away, is there any other spot for the dog bed out in the open?

---

What We Are Encountering:

• We are not having mold between our bed and the bed support
  
  
• Our bed is just too high, we have to be careful not to hit our heads on the slide out ceiling
  
  
• Because of this and the general issue of airflow in other parts of the bedroom, we are thinking of changing things up.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Installed a mattress underlay under the bed Dricore (in place for about a year).
    
    
  • Painted the wood bed support with antifungal paint (in place for about a year).
    
    
  • No issues with moisture/mold under the bed, only between the bed support and the outer slide-out wall. It's due to sewating walls most likely , a dehumidifier in that area would help quite a bit

---

4. General Air Flow and Moisture Situation

• Bedroom Door Removed – Since it’s just us, we keep the bedroom door off to allow maximum airflow
  
  
• Dehumidifiers – One in the bedroom, one in the living room, we had one in the bathroom but have moved it to between the bed and slide out for now.
  
  
• Ventilation
  • Kitchen vent is always used when cooking.
    
    
  • Showering is avoided in the RV whenever possible (alternative showering options used).
    
    
  • When we do shower, we open the vent and run the fan to prevent condensation. You're doing everything right in those regards.

 

[Riverbug]

In addition to the staple remover, get yourself a couple of automotive trim removal tools. They are very handy for removing a variety of trims, panels, etc., around the RV. You can get plastic versions of them too, but those tend to flex too much for many of the applications. Having a variety of those tools is extremely helpful.

 

[Steven@147]

You're doing what we would do to treat it, using dehumidifiers, Damp rid, air movement etc. I would use some bleach water to wash down the area then also treat with an anti-fungal spray.
I would check all the carpet under the bed frame step up portion, inside the closet and anywhere else to make sure it wasn't damp causing a reoccurrence, or remove the carpet and check underneath the carpet for mold.
.
When we were replacing the frame lag bolts up front, to get the carpet off the bedroom slide step up, I used a long big flat bladed screwdriver to get behind the carpet and pry it loose, which helped loosen and pull out the staples so I could see them, then I could use pliers to remove the staples.

I would check to make sure an exterior water leak getting inside the RV was not the cause instead of condensation. One time we had a problem with water running down the lower schwintek gear tracks and then getting past the exterior bedroom slide seals, then running inside the RV and water would puddle on the bedroom floor on the right side of the bed between the bed frame step up and closet door. In the area of your pictures. Now just in case we keep the bedroom slide (left side of the RV) a tad lower than the right, so any rain water tends to run off the track to the outside.
We also put tape on the exterior of the bedroom slide along the lower schwintec gear track. This also keeps the exterior bedroom slide floor dry during rains.

Good luck sorting it out,

 

[Lloyd Family]

DRICORE DuraDri™ Mattress Underlay for RV’s, Boat’s, Camper’s, and Bed’s Creating Air Flow for a Dry and Comfortable Experience

Amazon.com

 

[Dick Noble]

Try an ozone generator. I've had good luck with these. You will need a good one and a big one. They can be expensive. You will have to be sure the trailer is tight and do not be in it.

 

[Deb2]

Even if you only have advice on one part of this, we'd really appreciate it! No need to address everything—any insight is helpful.

We’ve been struggling with persistent condensation and airflow issues in our 337 RLS Reflection and could really use some advice from those who have tackled similar problems.

Temperature Conditions:

• The worst condensation happens during extreme cold (below 20°F with wind chill). We believe the temperature differential is a key factor.

Our Setup:

• RV Model: 337 RLS Reflection 5th Wheel
  
  
• Problem Areas:
  • Hitch-Side Cold Draft – Cold air enters on the hitch side of the bed, leading to condensation between the bed and the slide-out wall.
    
    
  • Moisture Under the Bed & Dog’s Sleeping Area – Condensation forms along the floor under our dog's bed in the closet alcove, leading to mold against the step-up.

---

What We Need Advice On:


1. Checking for Mold and Removing Carpet

• What We’re Planning to Do & Need Advice On:
  • Remove the carpet between the outer wall of the slide-out and the bed support to inspect the wood underneath.
    
    
  • Any tips for safely doing this in a slide-out?

• What We Are Encountering:
  • Moisture and mold on the wall and floor of the hitch side of the bedroom slide out between the bed and the slide out wall.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.
    
    
  • Moved one of the dehumidifiers into the slide-out corner.
    
    
  • Attached a small fan to the legs of the homemade night stand (has space around the support for airflow and a damp rid container) between the bed and the slide out wall

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • The homemade nightstand that has been in that corner for a year has space around the support for airflow and we had a damp rid container in there
    
    
  • There is a dehumidifier in the room

• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

2. Pulling Up Trim in the Closet Step Area

• What We’re Planning to Do & Need Advice On:
  • Remove the trim to inspect for mold and moisture.
    
    
  • Any advice on removing this without damaging the structure?

• What We Are Encountering:
  • We found moisture buildup between the bottom of our dog’s bed and the floor as well as mold on the step in the closet alcove
    
    
  • We suspect more mold behind the trim where the closet step meets the floor.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.

• What We Are Now Doing to Prevent Future Issues:
  • We have now placed her bed on a raised dog bed frame to maximize airflow even more than that provided by Dricore.
    
    
  • Attached a small fan to the clothing rack in the closet to increase airflow further.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Used Dricore Mattress Underlay between our dog’s bed and the floor and between the back of her bed and the closet step-up - moisture occurred where it was anyway
    
    
  • Removed the closet doors (her bed wouldn’t fit otherwise).

• Notable: We didn’t find moisture in the rest of the closet—only between the dog bed and the floor/step.
  
  
• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

3. Improving Bed Airflow & Lowering Bed Height

• What We’re Planning to Do & Need Advice On:
  • We are considering replacing the solid wooden support with a steel support that has lots of airflow and is shorter (bed frame)
    
    
  • How might replacing the bed support affect the slide-out’s function?
    • Any concerns about wiring, slide-out mechanisms, or movement?

• What We Are Encountering:
  • We are not having mold between our bed and the bed support
    
    
  • Our bed is just too high, we have to be careful not to hit our heads on the slide out ceiling
    
    
  • Because of this and the general issue of airflow in other parts of the bedroom, we are thinking of changing things up.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Installed a mattress underlay under the bed Dricore (in place for about a year).
    
    
  • Painted the wood bed support with antifungal paint (in place for about a year).
    
    
  • No issues with moisture/mold under the bed, only between the bed support and the outer slide-out wall.

---

4. General Air Flow and Moisture Situation

• Bedroom Door Removed – Since it’s just us, we keep the bedroom door off to allow maximum airflow
  
  
• Dehumidifiers – One in the bedroom, one in the living room, we had one in the bathroom but have moved it to between the bed and slide out for now.
  
  
• Ventilation
  • Kitchen vent is always used when cooking.
    
    
  • Showering is avoided in the RV whenever possible (alternative showering options used).
    
    
  • When we do shower, we open the vent and run the fan to prevent condensation.

---

5. Additional Thoughts & Photos

• We’ll include photos of what we’re dealing with. It’ll take a second because I’m going to post this first.
  
  
• Any suggestions on any section would be greatly appreciated!
  
  
• We’ll also update this thread with what we find and what ends up working (or not working) to help future forum members dealing with similar issues.

Edited because half the text ended up bolded for some reason.

We use that shrink wrap window film that's attached with double stick tape. Your metal frames may still sweat, but the windows won't, taking care of a big part of the problem. The tape doesn't always hold up everywhere along the edges, but it'll still be effective. Also, we recently got mold on the corners and backs of our dinette cushions. I wiped it all down with vinegar, twice. I'm considering either getting rid of them or trying something like DenDry. It's made to put under mattresses in boats to allow air flow and prevent mold. But, it's pricey.
Good luck! I hope you find your solution.

 

[Lloyd Family]

Use 4 lb buckets of Damp Rid and smaller sizes in small areas.

 

[tom christiansen]

First thing I learned about preventing condensation build up in cold weather was to crack the ceiling vents very slightly anytime heaters are used.
I assume this applies not only to travel trailers but any rig that encounters cold weather.
Interior circulation helps but the venting has been absolutely crucial.

 

[epargmann]

Even if you only have advice on one part of this, we'd really appreciate it! No need to address everything—any insight is helpful.

We’ve been struggling with persistent condensation and airflow issues in our 337 RLS Reflection and could really use some advice from those who have tackled similar problems.

Temperature Conditions:

• The worst condensation happens during extreme cold (below 20°F with wind chill). We believe the temperature differential is a key factor.

Our Setup:

• RV Model: 337 RLS Reflection 5th Wheel
  
  
• Problem Areas:
  • Hitch-Side Cold Draft – Cold air enters on the hitch side of the bed, leading to condensation between the bed and the slide-out wall.
    
    
  • Moisture Under the Bed & Dog’s Sleeping Area – Condensation forms along the floor under our dog's bed in the closet alcove, leading to mold against the step-up.

---

What We Need Advice On:


1. Checking for Mold and Removing Carpet

• What We’re Planning to Do & Need Advice On:
  • Remove the carpet between the outer wall of the slide-out and the bed support to inspect the wood underneath.
    
    
  • Any tips for safely doing this in a slide-out?

• What We Are Encountering:
  • Moisture and mold on the wall and floor of the hitch side of the bedroom slide out between the bed and the slide out wall.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.
    
    
  • Moved one of the dehumidifiers into the slide-out corner.
    
    
  • Attached a small fan to the legs of the homemade night stand (has space around the support for airflow and a damp rid container) between the bed and the slide out wall

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • The homemade nightstand that has been in that corner for a year has space around the support for airflow and we had a damp rid container in there
    
    
  • There is a dehumidifier in the room

• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

2. Pulling Up Trim in the Closet Step Area

• What We’re Planning to Do & Need Advice On:
  • Remove the trim to inspect for mold and moisture.
    
    
  • Any advice on removing this without damaging the structure?

• What We Are Encountering:
  • We found moisture buildup between the bottom of our dog’s bed and the floor as well as mold on the step in the closet alcove
    
    
  • We suspect more mold behind the trim where the closet step meets the floor.

• What We’ve Done So Far Since Discovering the Mold Again:
  • As a temporary fix before we start ripping things apart, we followed the instructions on Mold Control Fungicide.

• What We Are Now Doing to Prevent Future Issues:
  • We have now placed her bed on a raised dog bed frame to maximize airflow even more than that provided by Dricore.
    
    
  • Attached a small fan to the clothing rack in the closet to increase airflow further.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Used Dricore Mattress Underlay between our dog’s bed and the floor and between the back of her bed and the closet step-up - moisture occurred where it was anyway
    
    
  • Removed the closet doors (her bed wouldn’t fit otherwise).

• Notable: We didn’t find moisture in the rest of the closet—only between the dog bed and the floor/step.
  
  
• For the general airflow situation: see Section 4. General Air Flow and Moisture Situation

---

3. Improving Bed Airflow & Lowering Bed Height

• What We’re Planning to Do & Need Advice On:
  • We are considering replacing the solid wooden support with a steel support that has lots of airflow and is shorter (bed frame)
    
    
  • How might replacing the bed support affect the slide-out’s function?
    • Any concerns about wiring, slide-out mechanisms, or movement?

• What We Are Encountering:
  • We are not having mold between our bed and the bed support
    
    
  • Our bed is just too high, we have to be careful not to hit our heads on the slide out ceiling
    
    
  • Because of this and the general issue of airflow in other parts of the bedroom, we are thinking of changing things up.

• What We Tried Previously To Prevent Moisture (That Wasn’t Enough):
  • Installed a mattress underlay under the bed Dricore (in place for about a year).
    
    
  • Painted the wood bed support with antifungal paint (in place for about a year).
    
    
  • No issues with moisture/mold under the bed, only between the bed support and the outer slide-out wall.

---

4. General Air Flow and Moisture Situation

• Bedroom Door Removed – Since it’s just us, we keep the bedroom door off to allow maximum airflow
  
  
• Dehumidifiers – One in the bedroom, one in the living room, we had one in the bathroom but have moved it to between the bed and slide out for now.
  
  
• Ventilation
  • Kitchen vent is always used when cooking.
    
    
  • Showering is avoided in the RV whenever possible (alternative showering options used).
    
    
  • When we do shower, we open the vent and run the fan to prevent condensation.

---

5. Additional Thoughts & Photos

• We’ll include photos of what we’re dealing with. It’ll take a second because I’m going to post this first.
  
  
• Any suggestions on any section would be greatly appreciated!
  
  
• We’ll also update this thread with what we find and what ends up working (or not working) to help future forum members dealing with similar issues.

Edited because half the text ended up bolded for some reason.

We had similar issues on the mattress and put this underneath. It’s been good so far.

Amazon.com

 

[rudy558]

Get a few staple removers and knee pads, the carpet is stapled and runs under the lower trim. It should come out from under there without much difficullty once all the staples are removed. Don't be suprised if there are hundreds of staples!

Thanks for taking the time to respond to so many things!

I'm going to paste your comments and my responses to cut down on the length.

You: If you're parked for long term, seal off the hitch—even if it's just taping plastic and insulation around it.

Me: I never thought of that—great idea!​

You: Get a few staple removers and knee pads. The carpet is stapled and runs under the lower trim. It should come out from under there without much difficulty once all the staples are removed. Don't be surprised if there are hundreds of staples!

Me: Great call on the knee pads! Sounds like I’ll be spending a fair amount of time crouching just to get all those staples out. Thanks to your warning, I’ll also bring a magnetic dish to catch them—last thing I want is for anyone to step on one!​

You: Little muffin fans might help with airflow.

Me: Absolutely! We actually just got a few—hoping they make a big difference.​

You: Check the outside of the slide for openings in the seal and exterior trim along the floor—even a tiny pinhole can invite in moisture.

Me: Good call! We ran a little test where it rained. We had a dehumidifier going in that corner to see if water would still appear. We figured the air movement would prevent condensation but wasn't enough to fight off a leak. It seemed dry, but if there’s a tiny pinhole, it might not have been enough water to overcome the dehumidifier. I wonder if the soapy water method they use for checking propane leaks would work—watching for bubbles to spot any leaks?​

You: The dog sleeps sweaty and it’s wicking away—any chance there’s another spot for the dog bed out in the open?

Me: Not really, but I think we found a fix! We got a raised dog cot and put her bed on top of it. It was a little too big for the space, so I trimmed down the aluminum support poles. Seems to be working well so far!​

You: It’s due to sweating walls most likely. A dehumidifier in that area would help quite a bit.

Me: Agreed—hopefully we caught it early enough that widespread mold isn’t an issue yet!​

You: You’re doing everything right in those regards.

Me: Thanks—I really appreciate the reassurance!​

 

[rudy558]

In addition to the staple remover, get yourself a couple of automotive trim removal tools. They are very handy for removing a variety of trims, panels, etc., around the RV. You can get plastic versions of them too, but those tend to flex too much for many of the applications. Having a variety of those tools is extremely helpful.

 

[rudy558]

Great idea! I’ll place an order today—having something more geared towards trim will be great. I have a cat's paw, from what I see of the automotive trim kit, that will give me more options. We’re hoping to start pulling things up next weekend, so the order should arrive in plenty of time.

 

[rudy558]

You're doing what we would do to treat it, using dehumidifiers, Damp rid, air movement etc. I would use some bleach water to wash down the area then also treat with an anti-fungal spray.
I would check all the carpet under the bed frame step up portion, inside the closet and anywhere else to make sure it wasn't damp causing a reoccurrence, or remove the carpet and check underneath the carpet for mold.
.
When we were replacing the frame lag bolts up front, to get the carpet off the bedroom slide step up, I used a long big flat bladed screwdriver to get behind the carpet and pry it loose, which helped loosen and pull out the staples so I could see them, then I could use pliers to remove the staples.

I would check to make sure an exterior water leak getting inside the RV was not the cause instead of condensation. One time we had a problem with water running down the lower schwintek gear tracks and then getting past the exterior bedroom slide seals, then running inside the RV and water would puddle on the bedroom floor on the right side of the bed between the bed frame step up and closet door. In the area of your pictures. Now just in case we keep the bedroom slide (left side of the RV) a tad lower than the right, so any rain water tends to run off the track to the outside.
We also put tape on the exterior of the bedroom slide along the lower schwintec gear track. This also keeps the exterior bedroom slide floor dry during rains.

Good luck sorting it out,

Thanks for the reassurance that we're on the right track!

I hadn't thought about using bleach spray—do we need to worry about it damaging or discoloring anything?

Good call on checking the carpet under the bed frame—we’ll pull that up too. The closet seems to be mold and damp-free, but just to be safe, we’ve added a fan to the clothes rack to keep air circulating.

I really like your trick for loosening the carpet to make staple removal easier—we’ll definitely give that a try!

For the issue with your slide-out, do you think standing water on the track contributed? And what kind of tape did you use? Do you think it made a noticeable difference?

 

[rudy558]

DRICORE DuraDri™ Mattress Underlay for RV’s, Boat’s, Camper’s, and Bed’s Creating Air Flow for a Dry and Comfortable Experience

Amazon.com

Thanks for the tip! We actually already have one, and luckily, the mold isn’t under the mattress. But I really appreciate the advice!

 

[rudy558]

Try an ozone generator. I've had good luck with these. You will need a good one and a big one. They can be expensive. You will have to be sure the trailer is tight and do not be in it.

Interesting! I’ve never heard of these before, but I just looked them up.

Are you suggesting using one after we pull everything up to check under the carpet, to make sure we eliminate any leftover mold in the RV?

Have you found it to be a long-term solution, or more of a one-time treatment?

4o

 

[rudy558]

We use that shrink wrap window film that's attached with double stick tape. Your metal frames may still sweat, but the windows won't, taking care of a big part of the problem. The tape doesn't always hold up everywhere along the edges, but it'll still be effective. Also, we recently got mold on the corners and backs of our dinette cushions. I wiped it all down with vinegar, twice. I'm considering either getting rid of them or trying something like DenDry. It's made to put under mattresses in boats to allow air flow and prevent mold. But, it's pricey.
Good luck! I hope you find your solution.

Oh yes! We actually bought some of that but haven’t put it up yet. I really want to, though, because I think it’ll help prevent heat loss. Unfortunately, I think most of our issue comes from moisture condensing on the walls rather than the windows. On our RV, we’ve noticed little vents at the bottom of the windows that let condensation drain out instead of running down the interior walls—not sure if all GD RVs have that too.

We have DenDry under our mattress, and it’s been a game changer! Definitely worth the investment for mattresses. For dinette benches, I’m not sure, but since it worked so well for us, it might be a solid option. If not, removing them like you mentioned could be the best bet.

I hope you find a good solution too—moisture issues are such a pain to deal with!

Edit to add new thing: I'm trying to quote the response from epargmann above and can't figure out how. They suggested something that isn't DenDry and worked for them, maybe it would work for you with the dinette? Here's the link https://a.co/d/bIh2qCq

 

[rudy558]

Use 4 lb buckets of Damp Rid and smaller sizes in small areas.

Thanks for the suggestion! We actually have a lot of those, along with dehumidifiers running throughout the RV, so I don’t think they’ll fully solve the issue moving forward. But they’re definitely helpful for keeping moisture levels in check!

 

[rudy558]

First thing I learned about preventing condensation build up in cold weather was to crack the ceiling vents very slightly anytime heaters are used.
I assume this applies not only to travel trailers but any rig that encounters cold weather.
Interior circulation helps but the venting has been absolutely crucial.

That’s a great suggestion! We get a lot of wind warnings and rain here, so we haven’t been doing that, but maybe I should prioritize getting one of those vent covers so we can keep them open even in bad weather. Do you think cracking a window would have the same effect, or is the ceiling vent more effective for reducing condensation?