Sealing the Underbelly

Here's is whats needed to completely seal the underbelly from vermin, insects, and weather on a Landmark:

--2 tubes of black silicone
--20 yards of Gorilla tape
--1 can of expandable foam
--Small square of coroplast
--Sore muscles from lengthy crawling around

The Gorilla tape was mainly used to seal the areas where the coroplast was cut for the leveling and suspension systems, the front frame drop, and holes in the frame that were not used for electrical wires. The silicone was used around the coroplast perimeter and the expandable foam was used on the bottom of the end cap. The square of coroplast was cut to fit around the hydraulic ram holes in the frame. Those holes are HUGE and I wanted a material that would not scratch or interfere with the hydraulic rod extension or retraction.

I used to be a beekeeper and, believe me, you don't want bees taking up home in your underbelly area.

Dont forget the large holes on the frame where the hydraulic rams exit for the slides, and wiring. SOB are using alot of aluminum to attach the coroplast these days, instead of just self tapping screws now.

Rex, we just finished up doing the same basic thing you did to our unit this weekend. Once we had the underside and holes in the frame sealed up from bugs and critters we also sealed everything inside as well. Under the sinks we put expanding foam around all the holes where the water lines come up from the underbelly. Any place we found a hole or crack we sealed it and there were many.

The one place I am trying to figure out how to insulate next is behind the drawers in the steps going to the bedroom area. Those are open to the area behind the pass thru storage and will let heat and cold in.

Hunter11 said:

Rex, we just finished up doing the same basic thing you did to our unit this weekend. Once we had the underside and holes in the frame sealed up from bugs and critters we also sealed everything inside as well. Under the sinks we put expanding foam around all the holes where the water lines come up from the underbelly. Any place we found a hole or crack we sealed it and there were many.

The one place I am trying to figure out how to insulate next is behind the drawers in the steps going to the bedroom area. Those are open to the area behind the pass thru storage and will let heat and cold in.

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Great idea about sealing the inside too. Something else to do. Let me know what you come up with on the step drawer. I figure it will have to be done from the internal belly area. I spent some time in there this last winter trying to figure out why our water was freezing. The small heater hose, from the furnace, was lodged against another heater hose...once moved, we were ok for the rest of the winter.

What areas did you find holes inside beside the sink areas?

We sealed around the water lines under both sinks and I caulked around where the toilet supply lines comes through the floor. Something else we did was bought those foam outlet sealers and put them behind the face plates on all outlets on external walls. They may not do anything but it made us feel like we were sealing more places air could get in.

I pulled the rear wall of the pass thru storage area and took 1/2" pipe insulation and put it around every water line I could get to. Same thing with the fridge ice maker line under the slide out.

I never ever had any luck with gorilla tape staying on.
The RV dealer I work with uses Scrim Shield Tape and it sticks where ever you put it.
Its a Nylon weave tape with a super adhesive , kinda pricy but worth it.
search the net and you'll find it and I think one of the big chains has it too, Lowes, Menards or Home Depot.
I have a roll I keep on hand .

Sealing around the hydraulic ram holes can also be done with sections of inner tube attached to the frame with self-tapping screws. Some of the larger holes are best covered with a section of window screening and then applying the expanding foam. Uses less and gives it something to stick to.

View attachment 30585

bigdob24 said:

I never ever had any luck with gorilla tape staying on.
The RV dealer I work with uses Scrim Shield Tape and it sticks where ever you put it.
Its a Nylon weave tape with a super adhesive , kinda pricy but worth it.
search the net and you'll find it and I think one of the big chains has it too, Lowes, Menards or Home Depot.
I have a roll I keep on hand .

Click to expand...

Thanks for the name...I'll get some.