Coast Resorts Open Roads Forum: Replacing coroplast on entire camper underbelly

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Topic: Replacing coroplast on entire camper underbelly

Posted By: ewarnerusa on 06/19/17 03:31pm

I lost the entire coroplast liner that enclosed my camper's underbelly this weekend. I think the root cause was from some axle work I had done two years previous. I noticed then that they didn't fully reattach the coroplast to the frame very well at the axles. I had always meant to button it up better but never got around to it.... I figured water spray could get up in there and weigh it down and eventually have it tear. Turns out that air alone must have done the job.

While driving to the destination this weekend I was passed by a car that rolled their window down and gave me the signal that something was up. I pulled over and found about the third of the coroplast liner still attached to the very rear of the camper and dragging on the ground. The entirety of the rest of it was completely gone! Luckily it didn't tear any wiring out or propane lines. It did tear the handle off of my gray water dump valve. I had to screw a long wood screw in as a hack to get the tank dumped.

So has anyone else replaced the entire liner before? Dealer or DIY project? Cost? Thanks.

Posted By: Mortimer Brewster on 06/19/17 04:57pm

I replaced about 1/3 of the Coroplast on our trailer. I used 4 x 8 sheets which I bought at a sign shop. Prices varied wildly, so shop around. The best price I found was about $16 per sheet. Stainless steel fender washers and hex-head screws worked well for attaching the Coroplast. I did have to add some structure (2 x 3's) in order to have something to screw into. Be sure to overlap joints so it won't catch the wind. Working around tanks and gas lines were the biggest headaches. You can't have a joint under a tank.
I would also recommend adding insulation while it's open. I glued foamboard to the underside of the floor.

Posted By: NMDriver on 06/19/17 06:33pm

My bottom plastic came off 10 yrs ago and I never replaced it. I Zip tied all the wires up and added the plastic split wire guards. I have not had any problems with the trailer related to the absence of the sheeting.

I guess that it has some purpose other than to keep dirt off of the black tank and frame but it does not stop pack rats or mice and does not prevent blow outs so I left it off.

5er/2500Duramax/18ftBoat

Posted By: Hammerboy on 06/19/17 07:17pm

NMDriver wrote:

An added benefit of leaving it off is easy access to everything I would think.

Dan

2019 Chevy crew LTZ 2500 HD Duramax
2017 Wildcat 29rlx fifth wheel

Posted By: ewarnerusa on 06/19/17 08:57pm

My thought for benefits was the claimed heated underbelly. Although I got under there and looked and didn't see any heater vent pointed down there.

Posted By: opnspaces on 06/19/17 11:01pm

On mine the heater runs in a metal channel under the floor. I always assumed that the heated underbelly was just radiant heat from the metal ductwork as opposed to an actual vent under the floor.

2001 Suburban 4x4. 6.0L, 4.10 3/4 ton
2005 Jayco Jay Flight 27BH
1986 Coleman Columbia Popup.

Posted By: 4huskers on 06/20/17 04:25am

I replaced about half of it on our old trailer. Figure it kept road spray from getting up there ans soaking the underfloor.

Posted By: LarryJM on 06/20/17 05:22am

opnspaces wrote:

On mine the heater runs in a metal channel under the floor. I always assumed that the heated underbelly was just radiant heat from the metal ductwork as opposed to an actual vent under the floor.

Depending on where the ducts are they will provide SIGNIFICANT RADIANT heat to the underbelly area. I monitor my underbelly temp area with a remote thermometer and see this all the time.

Larry

2001 standard box 7.3L E-350 PSD Van with 4.10 rear and 2007 Holiday Rambler Aluma-Lite 8306S Been RV'ing since 1974.
RAINKAP INSTALL////ETERNABOND INSTALL

Posted By: ewarnerusa on 06/20/17 08:06am

4huskers wrote:

I replaced about half of it on our old trailer. Figure it kept road spray from getting up there ans soaking the underfloor.

This is my main worry and motivation for replacing it.

My furnace ducts also run in a center channel along the floor, but I can't see that channel from the bottom of the now-exposed belly. I'll look more closely though to satisfy my curiosity.

Posted By: ewarnerusa on 06/20/17 08:59am

Hammerboy wrote:

...An added benefit of leaving it off is easy access to everything I would think.

Dan

I have actually always wanted to rewire the main 12V connection from the power center to the batteries with fatter gauge. Then if I ever replace the WFCO converter with something more boondock-friendly I could minimize any voltage drop issues. But I thought removing the gazillion screws attaching the coroplast to drop it would be a chore. Now I have convenient access and I should take advantage and get that project done.

Posted By: ewarnerusa on 06/26/17 09:57am

I crawled around under there for a bit this weekend. I did verify that the center channel for the forced air furnace would be providing radiant heat for the underbelly. I also found a "vent" pointed down there. Directly beneath the furnace there was a nickel to quarter sized hole punched through that fabric/tarp-like barrier that opened up into some type of cavity. Surrounding the hole was metal sheeting like furnace housing itself. It looked like it was intentionally put there directly under the furnace, so I fired the furnace up and sure enough it blew air through that hole into the underbelly.

* This post was edited 06/27/17 04:33pm by ewarnerusa *

Posted By: shepfly on 06/26/17 06:19pm

I would suggest replacing the separate screws and washers with 1/4 thick vinyl moulding about 1 1/4 wide. Available at Home Depot,etc. This provides much better holding power a neater looking job. If you space the screws and mark the strips as to location, you can remove and replace your coroplast much easier. Dave

Posted By: rhagfo on 06/26/17 08:46pm

Well our 5er didn't have it before, but as we are going full time I decided to enclose it for warmer floors in the winter. Used 4'X 8' sheets from local plastics dealer for about $12 a sheet.
I also don't have too many issues if access is needed, just ran a length of RG6 coaxial cable full length for our Cellular booster. I took about an hour to. Drop the areas needed and snake the cable through, and reseal.

Russ & Paula the Beagle Belle.
2016 Ram Laramie 3500 Aisin DRW 4X4 Long bed.
2005 Copper Canyon 293 FWSLS, 32' GVWR 12,360#

"Visit and Enjoy Oregon State Parks"

Posted By: sarahm on 06/29/17 01:35pm

I removed mine for warmer floors. Insulated with attic batted insulation held in place with rigid foam insulation. Reattached sheets with stainless steel screws, and velcro. Sealed all holes around pipes with flexible vinyl material, and Gorilla tape. Only had one mouse this winter. She chewed threw the vinyl next to the tires. Noticed a big difference in temp, and fewer winter visitors. I think I could have just used the velcro. But I'm paranoid, and went with both.

Posted By: ewarnerusa on 06/29/17 01:45pm

I would be nervous about velcro alone, seeing as how mine tore way from air alone. It is certainly possible that I ran over something that bounced up and began ripping it away. I really don't know.

Posted By: sarahm on 06/30/17 10:51am

I was worried about the wind ripping the velcro off as well. Did a great job sealing the underbelly. I didn't have any problems with wasps, and only one mouse. I used screws without washers, and experienced some tearing around the holes. I would use washers with your screws. Go stainless steel screws.

Posted By: ewarnerusa on 08/14/17 10:51am

OP Update
While starting with asking the RV dealer for suggestions may seem obvious, I had avoided doing that expecting that I would need to drop off the trailer for them to repair and pay a fortune in parts in labor. Turns out they have coroplast available from a 70" roll that you can buy by the foot to fix it myself. Perfect! Except they are low on stock and I'll have to wait a week or so for them to get more. The sheet that came off is 70" wide that spans the distance between the trailer frame rails. Must be an industry standard. I believe they said $7/ft which would make it only slightly more expensive for the replacement parts than the ~$22 per 4'x8' sheet from Home Depot. Plus I'd much rather have it be a single continuous sheet going back on than multiple sheets. I'd be afraid of air getting between the sheets and ripping the whole setup off again.

Posted By: ewarnerusa on 07/23/18 02:44pm

Follow up, project done. The coroplast was around $170 from the dealer. The install took me several of weekends when I could devote some time to it. I learned some tricks along the way that I'll hopefully never have to try again. Main thing being to use jacks or blocks or whatever is handy to hold the sheet up against the camper underbelly. My original plan was to just start at one corner and keep it aligned as I progressed with screwing the new sheet back on. Eventually I'd use other means to hold up the coroplast but I didn't think it would be necessary at first. I should have just done it from the start, it would have helped make it easier to keep aligned as I progressed because despite my best efforts it still got out of alignment as I progressed. What I ended up using was a stool beneath the camper with bottle jack on top of the stool and then a roughly 2'x4' sheet of plywood on top of the bottle jack. I'd raise the jack and plywood until it pressed the coroplast up so all sag was removed. Then I'd start screwing it onto the frame. I'd move the jack setup along with me as I progressed.

Posted By: mikefos on 07/23/18 02:52pm

ewarnerusa wrote:

Good info, thanks for following up.

Mike and Kim
2012 Jayco Eagle Super Lite 308RETS, TST 507 TPMS
2010 Chevy 2500HD, Duramax/Allison, 2WD, Long Bed, Crew Cab, Duraflaps, AMP Bedstep
Equal-i-zer 1400/14K Hitch

Posted By: minnow on 07/23/18 06:59pm

^X2 Appreciate the followup and the tip on the stool/plywood and bottle jack.

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