Coroplast repair and insulation advice please!

[blakei]

Hi all, hoping for some veteran advice!

We had the TT in the driveway during Thanksgiving for in-laws to stay in. Somehow (I wasn't there) the toilet flush lever became stuck halfway down. With the city water hookup, the blank tank filled and overflow happened. Fortunately the tank started "empty"... although it never truly is. Regardless, we cleaned up & disinfected the inside and there doesn't seem to be any water damage.

However, leakage happened UNDER the trailer. Not sure how. But the Coroplast-sealed underside was swollen and dripping. I cut open the coroplast in a couple of big barn doors -- I expected to find the entire underside insulation full of icky water.

Well, I was right... partially. There is only ONE TINY PIECE of insulation between the tank bottom and the coroplast for the black and gray tanks. So much for "four season" and "fully insulated" trailer. Wow!

Question 1: any thoughts on what insulation to use to replace what I removed? Standard construction batts?

Question 2: any advice on how to repair the Coroplast? Had I known how little insulation was affected I would have made a much smaller cut. For now I am planning on doing some kind of screw backer and then using Gorilla / underbelly tape.

Many thanks!

[Cincinnati Kid]

Everybody has to cut the coroplast at some point. The trick is to make the hinge end at the front edge, to make road wind less of a factor. But it's not a problem to tape it up and carry on. I use this tape-

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

It's very sticky and made for this. Just clean the surface first. I use alcohol on a rag.

Funny story- Just this afternoon I had to cut some holes to reroute some wires. When I cut the first hole, in a location I hadn't cut before, MY LONG LOST RIGID FLASHLIGHT ALMOST FELL OUT OF THE HOLE! I had almost replaced it, but hadn't given up yet.

[TWP723]

You can buy the tape to repair Coroplast on Amazon. And I'd use regular housing insulation.

[ARoamer]

Originally Posted by Cincinnati kid

I use this tape-

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

It's very sticky and made for this. Just clean the surface first. I use alcohol on a rag.

Maybe I should be posting under the "I'm so old that" thread, but.. .
$60 for a roll of duct tape ??? Ouch.
But, the OP does have a long cut that could be a problem if it came loose at highway speeds. I'd screw a 1x wood strip along the leading edge then tape it.

I taped 30' of LED lights to the coroplast under my 5er with strips of el cheapo clear packing tape and 2 years / 6k miles they are still stuck there.

[Jerry713]

Originally Posted by ARoamer

Maybe I should be posting under the "I'm so old that" thread, but.. .
$60 for a roll of duct tape ??? Ouch.
But, the OP does have a long cut that could be a problem if it came loose at highway speeds. I'd screw a 1x wood strip along the leading edge then tape it.

I taped 30' of LED lights to the coroplast under my 5er with strips of el cheapo clear packing tape and 2 years / 6k miles they are still stuck there.

I hear ya. It's a lot of money for tape especially when Gorilla tape works pretty dang well. Flex seal would probably work too. There are cheaper brands of underbelly tape but will they work as well is the question. For me I would concentrate more on cleaning the coroplast well with 91% isopropyl alcohol and on the application of the tape (not touching the tape or area to be taped with my oily fingers and not letting any wrinkles in the tape) and not so much the specifics of the tape. Also if it's cold heat the coroplast up with heat gun or hair dryer before applying the tape it'll stick better.

[Cincinnati Kid]

Originally Posted by ARoamer

Maybe I should be posting under the "I'm so old that" thread, but.. .
$60 for a roll of duct tape ??? Ouch.
But, the OP does have a long cut that could be a problem if it came loose at highway speeds. I'd screw a 1x wood strip along the leading edge then tape it.

I taped 30' of LED lights to the coroplast under my 5er with strips of el cheapo clear packing tape and 2 years / 6k miles they are still stuck there.

Ok, you made me get out my calculator, lol.

The closest comparison I could find on Amazon was this- https://www.amazon.com/Gorilla-60253...52&sr=8-9&th=1

My tape is 4" x 180' ( $1.01 Sq. ft.)
The Gorilla is 2.8" x 75' ( $.89 Sq. ft.)

I bought this just for this purpose, and I keep it in the box it came in. It's peel and stick, and extremely sticky. And being 4" wide, I cut to length and use just one piece of tape per seam.
With narrow tape, I would be probably put one on the seam, and another on each side, overlapping, so I'd be using a lot more tape. So really, the way I use it, the Gorilla would cost more.

I'm a cheapskate, so it was difficult to spend $60 on a roll of tape, ($56 when I bought it about a year ago), but I'm happy with it.

Funny thing is, I can't remember ever buying Gorilla tape, even though I live in their world HQ, Cincinnati. I still use regular old silver duct tape. I'm going to have to get some.

[Marcm157]

I run a bus company with motorcoaches that do charter work up and down the east coast. One of the staple items in our crash kits we send onboard each of our motor coaches is a roll of Gorilla Tape. We have found it very useful in allowing a driver to make a temporary roadside repairs in many different situations. We found it to be some of the best quick repair tape out there.

[TaftCoach]

In fairness it's not duct tape. Different animal. The problem is that quantity they are selling seems like more for original construction or replacement than small repair.

[nfisherman]

It’s a long story but my camper had a bunch of RV underbelly tape on it when I bought it new from the dealer. It lasted about two weeks and fell off.

I’ve had much better luck with the 3-inch wide Gorilla taps that you can get at Home Depot. That stuff doesn’t let go.

[muckinfuss]

Good luck if you can get anything other than the tape made for Coroplast to stick longer than a week...unless you don't actually tow down the highway. I tried them all and finally went to my dealer..who gave me the stuff they use and I never had another problem. Like any tool, the right one for the job usually costs the most.

[LuckyDuck]

Originally Posted by muckinfuss

Good luck if you can get anything other than the tape made for Coroplast to stick longer than a week...unless you don't actually tow down the highway. I tried them all and finally went to my dealer..who gave me the stuff they use and I never had another problem. Like any tool, the right one for the job usually costs the most.

Do you recall the brand/type and whether it is available elsewhere?

[LukeDagny]

I found this link had some interesting information;

https://christinedemerchant.com/coro...ng-gluing.html

[TWP723]

The tape I used would destroy the CP before it peeled off. Had a backing kinda like Eternabond, but not as thick.

[muckinfuss]

Originally Posted by LuckyDuck

Do you recall the brand/type and whether it is available elsewhere?

My trailer isn't near me right now or I'd take a look at the backing. I got it from my dealer who is a Jayco shop. It's shiny, black, has threads running through it and is 4 inches wide. According to the service manager, the stickum cures after you peel the backing and apply so that it turns into some sort of bond with the coroplast. sorry, I don't have a brand or anything else in memory.

[nfisherman]

Maybe my dealer didn’t prep the coraplast well, but the underbelly tape didn’t work at all. It was 4 inches wide and had a braided look on the back side, almost like carbon fiber. It fell off into a big gooey mess after a couple of weeks.

I fixed tbe dealer’s mess with a new piece of coraplast, wiped the taped edges with a rag and mineral spirits. I applied the 3-inch wide Gorilla tape. It has held for 6 months so far with a few hundred road miles. It looks like new and I honestly think it would be easier to cut it than try to peel it off if I need to open the underbelly again.

[LuckyDuck]

Originally Posted by muckinfuss

My trailer isn't near me right now or I'd take a look at the backing. I got it from my dealer who is a Jayco shop. It's shiny, black, has threads running through it and is 4 inches wide. According to the service manager, the stickum cures after you peel the backing and apply so that it turns into some sort of bond with the coroplast. sorry, I don't have a brand or anything else in memory.

No problem. Thanks for the follow-up!

[TCNashville]

When I had to cut into my underbelly, I used black gorilla tape to seal it. That was 8 years ago and still going strong.

[blakei]

Wow, everyone, thanks for all the replies and links! I purchased some gorilla tape and found this roll which I may overlay since it's a few inches wider: https://www.amazon.com/dp/B0B3X9SPYH?th=1


I also think I'll screw into a thin board as suggested given the length of my cuts... newbie mistakes.


Any thoughts on packing insulation into the entire area v. just under the tank bottom as it was originally? I can't see more hurting as long is it's not going to hang up any wiring etc.

[440 scout]

As for replacing the insulation, if it got wet replace it. Some people remove all the fiberglass insulation and replace it with foam board insulation that they cut to fit in as needed. Foam board can get wet and still be ok to use once its dry because it keeps its shape and doesn't fall apart. Also did you see that silver space blanket looking blanket on top of the coroplast? When I pulled my coroplast down for the frozen pex connection at the bottom of the fresh water tank, I saw that silver stuff was never pulled across so that it was under the water tank and not having it in place may have contributed to the freezeup. (Happened during the Polar Vortex last year.) It's a big job but at this point you could pull the coroplast down to inspect the rest of your tanks, plumbing lines, make sure tank heating pads are actually glued to the bottoms of the tanks and check electrical wiring hanging loose. I don't know how your coroplast is secured along the edges but mine is held on with self tapping screws in a strip of aluminum that runs along each side which seems to work pretty good.

[wordsmyth]

Originally Posted by 440 scout

As for replacing the insulation, if it got wet replace it. Some people remove all the fiberglass insulation and replace it with foam board insulation that they cut to fit in as needed. Foam board can get wet and still be ok to use once its dry because it keeps its shape and doesn't fall apart. Also did you see that silver space blanket looking blanket on top of the coroplast? When I pulled my coroplast down for the frozen pex connection at the bottom of the fresh water tank, I saw that silver stuff was never pulled across so that it was under the water tank and not having it in place may have contributed to the freezeup. (Happened during the Polar Vortex last year.) It's a big job but at this point you could pull the coroplast down to inspect the rest of your tanks, plumbing lines, make sure tank heating pads are actually glued to the bottoms of the tanks and check electrical wiring hanging loose. I don't know how your coroplast is secured along the edges but mine is held on with self tapping screws in a strip of aluminum that runs along each side which seems to work pretty good.

Working on an underbelly issue and found your post very helpful. Thanks.