At the start of last season i had issues with my slide motor. when i replaced it i cut an access door in the corrugated plastic stuff. long story short that was the easiest day to access it. I sealed it back up with 'permanent' duct tape. as it turns out permanent is a bit of a misnomer...its coming loose. in fairness it did stay almost an entire year and 2500 miles of towing.is there something that would work better? or just redo every year.

If you Google "underbelly repair tape" you can buy a seam tape, but in my experience Gorilla Tape from Home Depot lasts the longest.

I use the foil looking air conditioning duct tape. I have never had a problem with not sticking . Works very good. Home Depot, Lowes or hardware stores sell it .

I'd try a better tape first. If that doesn't hold maybe try some scrap wood above the seams and screw both sides of the seam and tape over that.

I replaced the washers on the seams with fender washers and then used the new very wide Gorilla tape.

The tape used in RVs is called Scrim Shield tape and is available online such as here or can be purchased at an RV dealer by the foot. Mechanically fastening is better if you can do it, followed by tape. The tape can come off eventually as the coroplast is made from LDPE. For holes, landscaping expanding foam which is black/grey.

corrugated underbelly material...how to repair | Good Sam Community

BurbMan
Explorer II
Apr 07, 2015
If you Google "underbelly repair tape" you can buy a seam tape, but in my experience Gorilla Tape from Home Depot lasts the longest.
filrupmark
Explorer
Apr 07, 2015
I use the foil looking air conditioning duct tape. I have never had a problem with not sticking . Works very good. Home Depot, Lowes or hardware stores sell it .
RVcircus
Explorer II
Apr 07, 2015
I'd try a better tape first.

If that doesn't hold maybe try some scrap wood above the seams and screw both sides of the seam and tape over that.
Lauren
Explorer
Apr 07, 2015
I replaced the washers on the seams with fender washers and then used the new very wide Gorilla tape.
myredracer
Explorer II
Apr 07, 2015
The tape used in RVs is called Scrim Shield tape and is available online such as here or can be purchased at an RV dealer by the foot. Mechanically fastening is better if you can do it, followed by tape. The tape can come off eventually as the coroplast is made from LDPE. For holes, landscaping expanding foam which is black/grey.
tegu69
Explorer
Apr 07, 2015
I got my previous fw back from the dealership with warranty issues. After the first trip out, the tape they used came loose and was dragging behind the trailer. I thought it was crazy, taping a new camper the way they did. I forgot now, how many feet I got, but I just told them to get me the material and I would do it myself. I replaced the material from the cut to a support brace to the rear. I made the seam under the support brace, so it couldn't be seen. It was some work taking trim pieces off and everything, but it sure looked better than taping it and way more secure.
Dr__Blake
Explorer
Apr 07, 2015
Gorilla tape - I used it 2 years ago, still stuck like the day I put it on.
Helmsey
Explorer
Apr 07, 2015
+1 for Gorilla tape.
SoundGuy
Explorer
Apr 07, 2015
shutdown wrote:
... when i replaced it i cut an access door in the corrugated plastic stuff.

It's called Coroplast and has an endless variety of uses, including RV underbellies.
RJCorazza
Explorer
Apr 07, 2015
SoundGuy wrote:
shutdown wrote:
... when i replaced it i cut an access door in the corrugated plastic stuff.

It's called Coroplast and has an endless variety of uses, including RV underbellies.

Yup. I make large RC planes out of it also.
Gorilla Tape, aluminum rivits, or with some difficulty super glue (but absolutely permanent). With super glue the coroplast needs a very brief flame applied to both sides, then glued.