Under belly appears to be sagging or bulging

Bob&Jan · 05-09-2020, 08:27 AM

I have a 2019 Montana High Country. We bought it in August 2019. We are living and traveling full time.
Until yesterday I had looked underneath the RV noticed that the covering under the back portion was not flat.

Is this normal? If not, is a serious, like fix immediately, or can it wait until the next time get ready to travel? Is there a DIY fix for the problem?

Thanks for helping.

**JRTJH** · 05-09-2020, 08:51 AM

The underbelly covering is "COROPLAST" (corrugated plastic). It will sag naturally and droop a little as time goes by.

You stated, "Until yesterday I had looked underneath the RV noticed that the covering under the back portion was not flat."

What did you mean by that statement? Was "yesterday" the first time that you've looked at the coroplast and noticed it drooping? Or was "yesterday" one of many times that you've looked under the trailer and THIS TIME things are significantly different than what you saw on previous inspections?

In other words, have you just now noticed this condition with no previous reference or are there "dramatic changes" in the condition of the coroplast?

Keep in mind that the coroplast is only attached at the sides with very few "centerline supports" so some "drooping or sagging" is normal. On the other hand, if there is a significant change in how far the coroplast hangs down and it's significantly worse than in the past, then that is two different situations and may mean there's a problem that should be attended to before towing.

Bob&Jan · 05-09-2020, 09:14 AM

This is the first time I have looked under the RV. I will continue to check on it over time

**chuckster57** · 05-09-2020, 09:21 AM

Quote:

Originally Posted by Bob&Jan

This is the first time I have looked under the RV. I will continue to check on it over time

Just push on it, if it just flexes without any sign of liquid trapped, I would leave it alone. I have seen trailers come from the factory with both smooth and sagging coroplast.

gearhead · 05-09-2020, 10:40 AM

If it bothers you enough that you want to do something about it, you can add some cross bracing. I did it on our previous Montana HC and just did on the Landmark. You should be able to find 1 1/2" X 1 1/2" perforated angle at a good hardware/lumber yard. It will have slots and holes on both sides of the angle so you will have some flexibility on where to mount it. Measure the outside dimension of the frame, side to side. Six feet is probably what you will find. It's less worrisome if you drill through the on the outside of the I beam web where it is visible. Start with a good drill bit less than 1/8" for a pilot. The frame I-beams are pretty tough so be prepared. Wear EYE PROTECTION. I use a 1/2" electric drill. I used 1/4" stainless bolts with stainless nylon locking nuts and stainless washers, but use whatever you choose. Drill a hole appropriate for whatever size bolt you are using. I drill one hole and bolt that up before going to the other side. I paint the angle flat black before I install it and also grind the sharp corner off. You can use self drilling self tapping screws but a bolt with a nut just feels better to me and is always visible.
The perforated angle is light enough to easily handle but strong enough to hold the underbelly up.
I just don't like stuff hanging down and looking like it's about to fall off on the freeway in downtown Atlanta.

travelin texans · 05-09-2020, 10:49 AM

As temperatures rise the day will probably worsen, but as mentioned if it doesn't feel like liquid above it it's probably just normal sag.

ewbldavis · 05-12-2020, 07:55 AM

Tanks empty?

Sometimes the "sag" will increase when tanks are full as the tanks will sometimes sag, too.

locogk28 · 05-16-2020, 08:21 AM

on ours the brace for the holding tanks let go big sag

Bob&Jan · 05-17-2020, 01:42 PM

Thanks everyone. I am just going to watch it for now

CaptnJohn · 05-21-2020, 08:19 AM

Drill a tiny hole where it drops the most. If no liquid comes out a tab of Gorilla Tape and done.

roadglide · 05-21-2020, 11:44 AM

Quote:

Originally Posted by CaptnJohn

Drill a tiny hole where it drops the most. If no liquid comes out a tab of Gorilla Tape and done.

I suggested that but was shot down supposedly there is a procedure to find out if the underbelly has water. I would like to hear from the OP with the sagging underbelly maybe drinking light bear will help the situation.

**JRTJH** · 05-21-2020, 12:10 PM

I don't know if there is a specific procedure to confirm if water is above the coroplast. My only concern with drilling a hole in the coroplast is that in many places, the tanks and other items in the underbelly are in direct contact with the coroplast. If, by some unfortunate chance, someone might drill a 1/8' hole in the coroplast and the black tank is "directly above that plastic, laying directly on the coroplast, well, it may not make for a happy ending. Even if the black tank were empty and couldn't be felt above the coroplast, the next time the black tank is full, no doubt there'd be some "aroma to confirm a hole"....

I wouldn't recommend anyone drill holes in their underbelly unless they KNOW exactly what is above that spot !!!!!

**flybouy** · 05-21-2020, 12:16 PM

IMHO for the reasons John has stated drilling blindly into the underbelly is just as foolish as drilling thru the floor or bed of your truck blindly. Wires, pipes, tanks could be on the other side. Contact with any of that will be costly.

notanlines · 05-21-2020, 12:29 PM

Marshall, at first I thought maybe this thread was aimed at people like you and I...

**flybouy** · 05-21-2020, 01:02 PM

Jim, paranoia must be running rampant. I thought the same thing.

Fastfreddie5409 · 05-22-2020, 02:48 AM

We have a 2017 Cougar 30 RLI and experienced a similar issue with ours sagging under the center of the trailer. I did push a pin up the lower part of the sag and got water. It took the dealer a couple of times to find the problem which was at the rear corner where the water connections are. It was behind that panel at the black water connection. When I use the black water flush, that connection would leak and run all the way down to the black tank area in the center of the trailer.

roadglide · 05-22-2020, 08:19 PM

[QUOTE=roadglide;391340]I suggested that but was shot down supposedly there is a procedure to find out if the underbelly has water. I would like to hear from the OP with the sagging underbelly maybe drinking light bear will help the situation.[/QUOTE It appears my suggestion is missing about Poking a hole and have a bucket ready to catch liquid.

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