Old rats/mice nest in underbelly. Clean/sanitize underbelly or replace?

**lchambers** · 06-01-2021, 09:19 PM

We bought the 2016 in Mesa, AZ, in April, and drove it home to Montana. We dropped off the trailer at an RV repair place. The bypass and some of the lights were not working. They get into the underbelly and find the heating ducting and some of the wires eaten. The dealer won't clean out the mice/rat mess, and want a restoration business to do it. I contacted ServePro, and they will do it for $650.
Well, I'm trying to figure out if the old underbelly could be replaced, the old one is torn anyway? If so there would be much less cleanup and sanitizing from the mice/rats.

**WhittleBurner** · 06-02-2021, 07:13 AM

The Coroplast can be removed without ripping it up, it is screwed on. Easy to clean off. As for sanitizing, what process do they plan on using ? A spray sanitizer...spray and let dry.

The whole thing is more time consuming than difficult if you are physicaly able to do this on your own. It isn't overly difficult to remove the coroplast . Splice the wires back together and shrink wrap the connections, foil tape to patch the duct, remove the nest then replace insuation with refectix. To put up the coroplast get 2 extra hands a long 2x4 and start putting the coroplast back up. This could all be done in a long day or 2 shorter days would be my preferance.

**Cdburgerjr** · 06-02-2021, 08:33 AM

Do you have to stretch the coroplast or anything to get it back on? Or does it just lay right back up there?

**Ynot4me2** · 06-02-2021, 08:45 AM

Originally Posted by Cdburgerjr

Do you have to stretch the coroplast or anything to get it back on? Or does it just lay right back up there?

I've only read about, haven't done so yet. It's pretty much a 2 man job pulling it straight as you go little by little on each side. Using a 2x4 or plank across will help with the weight.

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**WhittleBurner** · 06-02-2021, 08:52 AM

Replacing is a 3 person job to make easier work out of it. 2 to hold and walk the 2x4 down the length of the trailer. A 10 ft length. This holds to material up as you replace the screws. Coroplast is not stretchy but can be pulled taught to help line the screws holes back up.

**DougSleeter** · 03-09-2024, 04:04 PM

Originally Posted by WhittleBurner

Replacing is a 3 person job to make easier work out of it. 2 to hold and walk the 2x4 down the length of the trailer. A 10 ft length. This holds to material up as you replace the screws. Coroplast is not stretchy but can be pulled taught to help line the screws holes back up.

Thank you so much Gary for posting this suggestion.

I've got a mice/rat problem and I've been wracking my brain for how they're getting into the unit. I've been plugging electrical access holes with Great Stuff gap filler, stuffing rat-repellent in the slider gaps, and setting traps, but they're still getting in.

Anyway, I removed the box that encases the heater ducting under the bed and it revealed a huge (approximately 5") hole in the carriage bottom with a 2" duct. So there is all the room in the world for any critter to enter the unit.

What a disappointment that Grand Design didn't seal that hole during manufacturing, if not for rat/mice control, then for thermal control. I sure hope they're reading this forum to make fixes in the future.

In any case, I'm going to try your suggestion to remove the Coroplast, then sanitize it, and seal up that heater duct hole while I have it open. Wish me luck. Looks like lots of physical work even though pretty simple.

**WhittleBurner** · 03-09-2024, 06:30 PM

We screened every hole we could find after having a rat find it's way in, don't forget to drop the spare and seal as much as you can up there.

**jim_de_hunter** · 03-09-2024, 06:52 PM

Originally Posted by DougSleeter

Thank you so much Gary for posting this suggestion.

I've got a mice/rat problem and I've been wracking my brain for how they're getting into the unit. I've been plugging electrical access holes with Great Stuff gap filler, stuffing rat-repellent in the slider gaps, and setting traps, but they're still getting in.

Anyway, I removed the box that encases the heater ducting under the bed and it revealed a huge (approximately 5") hole in the carriage bottom with a 2" duct. So there is all the room in the world for any critter to enter the unit.

What a disappointment that Grand Design didn't seal that hole during manufacturing, if not for rat/mice control, then for thermal control. I sure hope they're reading this forum to make fixes in the future.

In any case, I'm going to try your suggestion to remove the Coroplast, then sanitize it, and seal up that heater duct hole while I have it open. Wish me luck. Looks like lots of physical work even though pretty simple.

Our Grand Design has that same large hole/small duct blowing into the belly. I thought that I would go ahead and seal it but then I considered air flow. If the only way for the cooled air to leave the underbelly is through that large hole around the duct, then sealing the hole would cause the underbelly to only pressurize. Heated airflow would cease once the belly pressure reached the static pressure of the air flow. I've left it the way it was shipped from the factory for now.

**livinthelife** · 03-09-2024, 08:34 PM

Originally Posted by jim_de_hunter

Our Grand Design has that same large hole/small duct blowing into the belly. I thought that I would go ahead and seal it but then I considered air flow. If the only way for the cooled air to leave the underbelly is through that large hole around the duct, then sealing the hole would cause the underbelly to only pressurize. Heated airflow would cease once the belly pressure reached the static pressure of the air flow. I've left it the way it was shipped from the factory for now.

How about putting a screen on it to stop unwanted guests?