Thread Tools Display Modes
Old 11-12-2018, 03:01 PM   #1
Senior Member
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 3,689
Undercoating a Travel Trailer

With some recent projects I've been spending a lot of time under my trailer. While lying on my back and looking at the bottom I noticed that only the center portion between the frame members appears to be "Water Resistant". The plastic cover looks like it would provide a pretty good barrier to any water and road chemicals tossed up from a wet road from reaching the water sensitive pieces (anything wood).

On either side of the frame the floor is covered with a fabric that doesn't look quite as water resistant. In fact it looks just like the landscape fabric one puts down before they make a flower garden to keep weeds from sprouting.

My question(s):

Is this fabric truly water resistant (I'd say water proof but that would imply that NO water would pass through) or if driving in a rainstorm does it allow water to migrate through?

Has anyone ever sprayed any of he rubber based undercoating materials over the fabric type underliner to make sure no water migrates up into the floor and whatever insulation that might be there?

I live in an area noted for its rainstorms and in October I encountered a lot of rain in Wyoming where it's not noted for rain. Since I like to travel regardless of season and want to make sure I have no "bottom up leaks" is undercoating a viable option. I have already sealed the plastic panel around the edges with aluminum tape so it's pretty much handled. My thoughts are now focused on sealing the rest of the underside with special attention in the wheel well areas.

Anyone been down this path before?

I have it on my dog's authority that an afternoon nap is acceptable.

Politically Incorrect since 1943

2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan
TitanMike is offline   Reply With Quote
Old 11-12-2018, 03:14 PM   #2
Senior Member
Join Date: Jul 2009
Location: Warsaw,NC
Posts: 7,083
If you could just spray it on the frame but on anything else I would think it would gum everything up

2015 Cedar Creek 32RL
2012 Silverado 3500HD SRW
spock123 is offline   Reply With Quote
Old 11-14-2018, 09:08 PM   #3
Senior Member
CincyGus's Avatar
Join Date: Nov 2018
Posts: 364
I would also be concerned about it not drying out due to impeding air movement if you made it more water resistant. Water in itself isn't harmful. It's when something absorbs water and stays wet with no where for it to go or no way for it to dry out.
2015 GMC 2500K Denali, 2019 Forest River Wolfpack 23Pack15, 2014 EZGO Golf Cart
CincyGus is offline   Reply With Quote
Old 11-14-2018, 09:56 PM   #4
Senior Member
rsdata's Avatar
Join Date: Aug 2014
Location: Northern KY
Posts: 2,817
One of the first things I did when I got my new hybrid home back in May 2014 was to tie up the hanging brake wires and tank sensor wires covering them using a couple of different sizes of wire loom I got at HFreight then using cable ties to make a neater and less hanging install. I also have that crinkled plastic under floor you describe.

I then used about 6 large 16 oz cans of spray-on undercoating, covering all the brackets and metal on the underside, and also the metal exposed in the wheel wells. I covered that area pretty well as I recall. Four years later, as I crawled under this summer I did not see any problems developing from moisture... and I live in the Ohio River valley near the Licking river 2 miles away... lots of moisture in the air most of the year...
ďToo much of anything is bad, but too much good whiskey is barely enough.Ē Ė Mark Twain

2014 Shamrock 183
2014 RAM 1500 Bighorn Crew Cab, HEMI, 3.21 gears, 8 Spd, 4X4 TST TPMS
rsdata is offline   Reply With Quote
Old 11-15-2018, 03:51 PM   #5
Join Date: Mar 2017
Posts: 30
Spray this stuff all over anything that can corrode.
Brickie is offline   Reply With Quote
Old 11-16-2018, 01:45 AM   #6
Senior Member
SailorSam20500's Avatar
Join Date: Jun 2016
Posts: 2,451
At a seminar in Goshen last summer, I asked about coating the wheel well area with undercoating to provide some protection against a tire failure. The presenter thought it was a good idea. Haven't gotten my butt in gear yet to actually do it though....
Save the Earth. Itís the only known planet with Beer.
S.E. Mich.
Flagstaff 26FKWS / 2018 F-150 3.5 EcoBoost SCrew
SailorSam20500 is offline   Reply With Quote
Old 11-17-2018, 01:46 AM   #7
Senior Member
Mad Cow's Avatar
Join Date: Jan 2018
Posts: 305
Originally Posted by Brickie View Post
Spray this stuff all over anything that can corrode.
Something else that is pretty effective is the Amsoil Heavy Duty Metal Protector. I use it on frames and such with my heavy commercial equipment. Doesn't harm wiring or plastic components.
Mad Cow is offline   Reply With Quote
Old 11-21-2018, 01:36 PM   #8
Junior Member
Join Date: Sep 2013
Location: Plainfield, IN
Posts: 25
After a blowout on the front right of my 5er, the fabric was ripped out and I could see the wood chip underlayment of my floor. I sprayed a can of black rubber paint over the area, probably 9" x 30". When I got home, I sprayed a second can of the stuff and just before i screwed the diamond plate to the area, I emptied a can of foam in the space. Hope this will keep the floor from getting soft...

davidgle is offline   Reply With Quote

trailer, travel, travel trailer

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 08:51 AM.