Under Belly Bulge

[murry135]

We have a 2013 Key Largo. Included in our coach is the YETI Package which includes fiberglass insulation under waste water tanks to help keep tanks and under belly space warmer. As our waste water tanks fill our under belly grows and bulges out and downward. I had this issue looked at twice by two different repair shops recently and all they could find was a broken waste water tank bracket which was repaired. Last week a friend pointed out to me again the extreme bulge downward again. I am looking for ideas and suggestions. Is this normal or is there an underlying problem. I hate to have to personally take down the coroplast again since it is tightly sealed by the last repair shop.

 

[Bob&Patty]

2 things come to mind. As the holding tanks fill up, they do expand/ push down on the coroplast. If you have driven in the rain or had some heavy rain while sitting, water will get into the underbelly. If this is the case, you can drill a 1/4" hole in the low spots so the water will drain out. Just be careful how deep you drill. Ya dont want drill into any holding tanks. Put a piece of rubber hose on the drill bit so only a little more than a 1/4" of drill bit sticks out.

 

[JohnDar]

I think it's the nature of the material to sag in the center where it's not fastened to the framing. If a holding tank is suspended close to it, it will expand into the mounting straps as it fills and may change the look of the bulge. Driving though rain/wet roads may toss some water in there, even if they "sealed" the edges (I don't think I'd do that). There are enough small holes in the frame for some water to get sloshed in, unless you've sealed all of them, too. If you look at the holes for the main and kitchen slide rams, they're right over the tires and big enough for a squirrel to get in. I put rubber flaps over mine.

 

[MCTalley]

Our front gray tank bulges down as it gets full. I took down a corner of the coroplast to check on it and found that the straps are mounted only about 1/4 way in from either side and even when the tank is fairly full, it doesn't touch the straps (I assume the tank is resting on flanges up top). This leaves the center half of the tank to sag downward and push the coroplast down (which unfortunately means that the back section wants to pull away from the screws and requires a bit of Gorilla Tape to seal up).

I've debated adding another strap in the middle and cinching it up a bit tighter to even out the sag.

 

[jnbhobe]

I have a piece of angle iron bolted across the frame rails under the fresh water tank to keep the sag out.

 

[SeattleLion]

I have a piece of angle iron bolted across the frame rails under the fresh water tank to keep the sag out.

Did you have to drop the coroplast to do that? was it hard to do?

 

[jnbhobe]

not hard all I just took a 6 foot piece of angle iron and put a bolt in each end

Sent from my DROID RAZR using Tapatalk

 

[murry135]

I believe our bulge is caused by the extra insulation taking up any space that is normally available on units w/o the extra insulation package. It is dry in that area of the under belly and sealed quite well from last service check. I do like the angle iron fix however I wonder if over time the iron bar will wear through the plastic tank with road vibration and movement.

 

[danemayer]

I believe our bulge is caused by the extra insulation taking up any space that is normally available on units w/o the extra insulation package. It is dry in that area of the under belly and sealed quite well from last service check. I do like the angle iron fix however I wonder if over time the iron bar will wear through the plastic tank with road vibration and movement.

Hi murry135,

Our 2011 Landmark came with both fiberglas insulation and radiant barrier foil in the underbelly, and this was before the Yeti package was offered. With the Yeti package, you get the tank heating pads, heat tape on the fresh line, radiant barrier foil in the front and rear caps, and radiant barrier foil in the slide floors - although it's possible the slide floors on Landmarks may now come standard with that radiant barrier.

I've had the coroplast down and the insulation under the gray #1 tank flattens to a pretty thin profile and isn't putting much pressure on the coroplast. Usually the tank expansion does this. But if you ever get water in the underbelly, it will also cause a bulge that may not go away when the water is drained.

 

[f250dieseldad]

I have a piece of angle iron bolted across the frame rails under the fresh water tank to keep the sag out.

That's the same thing I did. I used old bed rail that I picked up on garbage day.

 

[f250dieseldad]

I believe our bulge is caused by the extra insulation taking up any space that is normally available on units w/o the extra insulation package. It is dry in that area of the under belly and sealed quite well from last service check. I do like the angle iron fix however I wonder if over time the iron bar will wear through the plastic tank with road vibration and movement.

There you go, thinking to much again

 

[jnbhobe]

I believe our bulge is caused by the extra insulation taking up any space that is normally available on units w/o the extra insulation package. It is dry in that area of the under belly and sealed quite well from last service check. I do like the angle iron fix however I wonder if over time the iron bar will wear through the plastic tank with road vibration and movement.

Actually Jim on this rig I used a piece of 1 1/2 X 3 X 3/16 tubing so it has nice radius corners.

 

[murry135]

I like that much better. Rectangle tubing better support and surface area. Will go this way.

Murry135/Capt. Wingnut

 

[aatauses]

I have a 2010 3670 BH and also had the bulge in the underbelly. However after 5yrs of full timing my shower gray tank did chafe through and created two holes in the tank. I decided to replace the tank rather than have it repaired. HL was great with customer service and also gave me some advice when putting in the new tank, put a piece of 3/8" plywood on the bottom of it and run the straps under that---this has helped alot on the bulge. You could take down the underbelly when the tank is empty and cut a piece of plywood and carefully slide it under the straps.
al
currently on the road in CA

 

[MCTalley]

I have a 2010 3670 BH and also had the bulge in the underbelly. However after 5yrs of full timing my shower gray tank did chafe through and created two holes in the tank. I decided to replace the tank rather than have it repaired. HL was great with customer service and also gave me some advice when putting in the new tank, put a piece of 3/8" plywood on the bottom of it and run the straps under that---this has helped alot on the bulge. You could take down the underbelly when the tank is empty and cut a piece of plywood and carefully slide it under the straps.
al
currently on the road in CA

Hmmm. I like that idea. Seems simple enough.