Tuesday, October 3, 2023


My RV’s driver side floor is wet but not under the dash. Where should I look?

Dear Dave,
We are on a trip in our RV and I found that the floorboard where my feet go on the driver’s side was wet. It wasn’t wet under the dashboard, just under my feet. We did drive through some rain. Your thoughts? —Diane, 2007 Winnebago Vista

Dear Diane,
Your Winnebago Vista is a Class A unit with the driver and passenger cab made of steel welded at the Metal Stamping facility in Forest City.

The steel cab has a welded flat floor and firewall, and there are several places where moisture can penetrate if the weld cracks.

Here is a diagram from the website of your model. You can see the horizontal and vertical seams.

This is the driver and passenger cab in a 2003 Winnebago Brave that we installed new flooring in.

Check underneath the front cap

I would suggest getting underneath the front cap on a creeper and spray every joint you can find with a sealant such as undercoating or Flex Seal. I would start with the horizontal firewall that meets the floor which is at the #7 in the upper diagram. Then do all around the engine cover, which we call the dog house, and along the vertical corner of the firewall to floor. Hit the seat pedestal bolts and all along the wheel well.

Another place to look is the outside sidewall to floor joint, which has a trim piece that is secured to the lower chassis foundation with screws and has sealant and a bulb cover.

Also, check the roof cap where the hard fiberglass cab meets the roof material. This has a “J” channel and self-leveling lap sealant. If this sealant has cracked or moved, moisture can penetrate and collect in the upper metal frame of the cab, then run down the side through the hollow A pillar and come out at the floor.

I have also found clearance lights at the top of the cap cracked and allowed moisture in and it ran down the A pillar to the floor.

Finally, the driver side window has butyl tape between the frame and the sidewall. It can shrink and crack, and moisture will come in and run down the inside of the sidewall.

These all need to be resealed with the appropriate sealant. Winnebago has recommendations for sealants here.

 You might also enjoy this from Dave 

How do I find what’s causing the water leak in my RV?

Dear Dave,
While city water is hooked up to my RV, the water starts to leak, causing the living room floor to leak. What could this be? —Jason, 2001 Tiffin Phaeton

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


We have a popular forum for Ask Dave. Please be as brief as possible. Attach a photo or two if it might help Dave with his response. Click to visit Dave’s forum. Or send your inquiries to him using the form below.

Click or drag a file to this area to upload.


Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


4.8 4 votes
Article Rating
Subscribe to comments
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments

Sign up for the

RVtravel Newsletter

Sign up and receive 3 FREE RV Checklists: Set-Up, Take-Down and Packing List.