Underbelly plastic cardboard weatherproof, toast?

Aceallenk · 05-21-2022, 07:00 AM

I'm not sure what this stuff is called, the black plastic cardboard underbelly waterproofing material the factory installed to keep out the elements/rodents/etc. Over the winter mine decided to tear/crack/whatever pretty much right across bottom of the trailer. I suspect from old age and brittleness, -40 degree temps, and lots of wind. SO what have any who also encountered this dilemma done to repair it, or replace it. Has anyone tried resheeting it with thin 1/4" plywood, of course weight becomes a factor. Suggestions welcome if you fixed your with an alternative material, what used, or even seen or heard of something, type thing. I never noticed this over the winter, or happened with the huge winds of a few days back, but yesterday was replacing my spring bushings and there it was, hanging down there, flapping in the wind, welcoming the little critters to a new home.

007matman · 05-21-2022, 07:07 AM

It's called Chloroplast Plastic sheets.

Try a sign shop, your local hardware store, or RV supply. I would not put plywood there. It'll attract and absorb moisture. It's also a lot heavier.

Aceallenk · 05-21-2022, 07:49 AM

Thanks 007 Matman. I think that's probably the best route to take. Good point about the moisture regarding plywood so on the search for Chloroplast it is. Gonna be a fair task, but it'll outlast me..

**Lloyd** · 05-21-2022, 10:17 AM

I haven't had to do anything with mine ----yet. (knock on wood)
Mine has a thin vinyl/plastic type covering that spans the whole under side of the trailer.

In the past a lot of the guys used Coraplast to replace it.
Comes in 4X8 sheets.

Here is a few links to it.
https://www.crossroadsowners.com/for...lly-15938.html
https://www.crossroadsowners.com/for...last-1663.html

Aceallenk · 05-21-2022, 10:34 AM

Thanks Lloyd. The stuff on mine right now is very thin to, about 3/32" thick, probably less than 1/8" black and one single piece front to back, kinda cardboard style corrugated plastic/nylon stuff. I just went into town and picked up a half dozen sheets of the chloroplast stuff. I'm sure this will work awesome. Got a few good thoughts/ideals to assist with installation, but will post those after I get started tomorrow and see how everything goes and pans out. I suspect it'll take a week to install them, removing what's there, crawling around under the trailer. First things first is finish the other side leaf spring bushings today.

**mark5w** · 05-21-2022, 10:59 AM

When you have it down, inspect the bottom of the rv and remove junk, seal holes and add more insulation if needed. Also, consider re-supporting your black, gray, and fresh water tanks.

coastn · 05-21-2022, 11:50 AM

X2. Excellent advice!

MarkCO · 05-21-2022, 11:53 AM

Yep, Coroplast. The factory does not generally do a good job of installing it, and if the techs need to repair, they just cut it. All kinds of stuff hanging down. The ramsets they use to put it up tend to come out over time as well.

I have some materials to slowly redo mine over the next year. Better foil wrapped foam board insulation, Aluminum T stock, self tapping screws, expanding foam. I am going to create access panels as well.

007matman · 05-21-2022, 05:50 PM

Quote:

Originally Posted by MarkCO

Yep, Coroplast. The factory does not generally do a good job of installing it, and if the techs need to repair, they just cut it. All kinds of stuff hanging down. The ramsets they use to put it up tend to come out over time as well.

I have some materials to slowly redo mine over the next year. Better foil wrapped foam board insulation, Aluminum T stock, self tapping screws, expanding foam. I am going to create access panels as well.

I'd like to see how you do that. Post up a thread when you do it.

Papa-T · 05-22-2022, 09:16 AM

You can use wide black gorilla tape. Like the 6” wide.

660catman · 05-24-2022, 04:42 AM

I had to redo a section of my coroplast. The replacement coroplast from the dealer was thicker and way better than the original on the trailer. I also bought some of the RV tape and it sticks real good.

Campingmom1960 · 05-24-2022, 12:27 PM

Flex Tape works well, too.

007matman · 05-24-2022, 12:28 PM

I used Gorilla Tape.

markandkim · 05-25-2022, 06:00 AM

Gorilla Tape is the best.

**dagst1** · 05-25-2022, 06:17 AM

Gorilla Tape followed by a heat gun and you will not be able to remove it.

Aceallenk · 05-25-2022, 08:33 AM

Let me tell you, this is one hell of a job @ 65, in pretty good shape, and thank God I hung lots of gyprock over the years, cause this is the toughest hanging of sheets ever, trust me lol. I'm about half done and it looks really good, but I figure if I can even only hang 1 sheet per day "oh well," but yesterday got 2. So what I been doing is: on this trailer between the frame rails, there are cross members that are running every 4 feet, these are key to adding supports holders for the center of the sheets. Now because of my fresh water tank location, this was my starting spot for the first sheet. These support holders are just short pieces of 2x4 put on with double sided tape and impossible to remove and where the 2 sheets meet each other, I added a length of 3/4" x 1 3/4" from frame rail to frame rail using clear pine no knots. This makes the sheets butt together perfectly with maybe adding about 1-2 pound of weight per sheet. Now on the sheets of coroplast before I install them I use gorilla duct tape on both ends to eliminate water that can get between the layers of the sheet. Remember you can only use 6 feet of every 8' sheet and you don't want water getting between the layers and duct works perfect for that. Now I also use more 3/4" x 1 3/4" clear pine to hold up the coroplast under the frame rails. ( I previously also did this to the factory coroplast and eliminated there big heavy flatwashers and selftap bolts, with all there waves and mouse hole openings) So at the moment I'm undecided if I'll also add duct tape to where the 2 sheets meet each other as if any water gets in there, there's no place for it to escape and theres no chance of them flapping about as I put a wide head low profile screw every 8" and they work slich. One thing I'd bet on, I don't think you could ever hire someone to do this for you without breaking the bank or exceeding the value of the trailer. The cost of the material is nothing basically ($300CAD) but the labor would would be scary, and you'd better be watching closely to.. I'll add a few pictures of the final overall as no two trailer would be done the same as not two sheets are done the same. "One sheet at a time" and one more thing, spend a day and tie up all the wires, hot air duct tubes, etc before you begin, and you add your all weather insulation to each sheet with double sided tape just before you finally screw it on.

**Lloyd** · 05-25-2022, 09:41 AM

Al, are you placing that 3/4" x 1 3/4" clear pine on the outside of the coroplast?

Aceallenk · 05-25-2022, 12:35 PM

Quote:

Originally Posted by Lloyd

Al, are you placing that 3/4" x 1 3/4" clear pine on the outside of the coroplast?

Yes, to keep the coroplast up tight against the frame so there's no waves or openings for critters to get into the underbelly. I did that as mentioned to the factories black plastic also to keep it tight to the bottom of the framerails. The factory used big heavy washers spaced every foot or more, and it had waves in the coroplast that made easy access for mice to walk through. there use to be a wave probably with a 3/4" opening before I removed the washers and ran 3/4" wood, that sucked up there mess and made there factory job mouse proof and just painted the wood black, incase someone should see that 100 miles an hour on the highway lol.
Lloyd I'm aloo running a strip of the 3/4"thick x 1 1/2"wide x aprox69" long between the(left and right) 2 frame rails where the 2 sheets of coroplast meet each other. This way the 2 sheets sit flat with each other. Remember the 4x8 sheets run across the trailer, not with the length of the trailer, thus you lose 2 feet from every sheet, but a lot easier to handle. and I use gorilla duct tape to seal the ends so water can't get between the 2 layers of the coroplast material. Remember its like cardboard so the tape eliminates the chance of water getting in there, which is something I found with the old stuff when I removed it. that adds a lot of water and weight type thing

660catman · 05-25-2022, 01:52 PM

It’s definitely not a fun job. I did 15’ of the 26’ on my ZT260BH from the back forward. Fun work at the axle hangers and the dump pipe. Laid a tarp down on my gravel driveway. That hurt once in a while. I had an old gazebo which I used the 3/4” square tubing to add more support for the coroplast. I siliconed the top of them to press on the coroplast so there was no movement after it set.

egrum · 05-26-2022, 02:34 PM

Home Depot sells Plastic stuff, looks just like cardboard, unfortunately can not remember the name of the stuff. It comes in Red, Black and White.

You may have to buy several sheets but since it comes in 4 foot X 8 foot, 1 sheet should be able to reach across the frame rails, then I would use Gorilla Tape on the seams, both sides to keep everything sealled. You could over lap them a bit, just make sure you get the lap facing the right (backwards) direction so the wind at highway speeds does not catch it. Not sure of pricing but the stuff is durable.

Finally I am not sure where you are but here in Calgary there is another company (Norwesco Industries (1983) Ltd) that sells the stuff and it is cheaper than HD.

Good Luck

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