What's beneath this

[DryFly]

What's beneath the rub rail?
I crawled under my 72 Argosy 20 to begin to re-attach the belly pan which is partially hanging down due to vibes from a bad axle. I've got the Argosy parked in my drive way and it's been raining a lot. When I pressed up on the belly pan water started coming out at the (unattached) seam. So now I'm trying to figure out where the leak is. I've got the roof sealed up nicely and windows are protected with a tarp pending better weather. So I'm suspicious of the rub rail but I don't know how it's constructed. Can water be getting in between the rub rail and exterior skin, then running down to the belly pan? Should the seam be caulked all the way around the trailer? What purpose does the rub rail fulfill? With all the talk about rotted floors (I have none) and leaks, I'm starting to wonder if this trailer's worth it. I hate leaks!
Here's a photo of what I'm calling a rub rail.

[wahoonc]

Yes.

The belly curve wraps are on top of the side skins. When I re-installed my rub rail I put a bead of sealant just above the rivet line then put the rivets in, then put another bead along the top edge.

Aaron

[dznf0g]

If it is like the AS, yes. I believe you will find the curved wrap panel riveted OVER or OUTSIDE the side skin. If there is a leak at the top edge of the "rub rail" it will run into the inside of the curved panel and into the belly.

My AS did this, I sealed the top of the rub rail only and it stopped.

This is an easy check. When it rains and the TT is in place, if you see the water drip off the curved panel to the outside of the curved panel/belly skin joint - all the way around- there are no leaks in the rub rail. If you see water coming FROM the joint of the belly skin and the curved panel, you have a leak in the rub rail.

Additionally, I am from the school of only sealing the top edge, so any water trapped behind the rub rail has an exit.

[Melody Ranch]

Water can get into the area between the rub rail and the skin. All that rub rail is ..is ashallow shaped "U" piece of formed aluminum. It is screwed on over the overlap of the body skin and the belly skin. Thats Body OVER the belly skin. Seal that seam will help. At the front and rear ends the rail always seems to gap. I Vulcum the seam all around the trailer, then install the rub rail, with vulcum on the screws. I then run a seam seal along the top and bottom of the rub rail. Anywhere that water can get in side...it will gravitate to the "U" channels (where the rub rails are screwed into.) Up at the front frame and rear at the frame water can travel unimpeded into the belly. The belly is not designed to be waterproof. It also has insulation inside there. Any water coming in will be involved with that insulation. You probably squeezed some saturated insulation to get your water. I worry more about air circulation to evaporate than I do about sealing the pan.

[DryFly]

Thanks for the quick feed back. So if I understand this correctly, the bottom curved panel, the part that comes out below the rub rail and down to the belly pan, is riveted over the main body skin, and then the rub rail covers the seam up? Stupid question, but wouldn't it be more water tight to have the bottom curved panel under the side skin?
Also, should I pull the rub rail off entirely, caulk the seam, re-attach the rub rail and caulk the top seam?

[DryFly]

Melody Ranch and all, that brings another question. Since the belly pan impedes ventilation, and water can get in and soak the insulation and eventually rot the floor, is there an issue with just removing the insulation altogether?

[dznf0g]

Dry, If you are going to remove the belly skin, I would get rid of the pink stuff and consider something else...like rigid foam, or prodex,etc. There are varying opinions on what to use and how to use it. Search on insulation and read a lot of stuff. And yes it would make water shedding sense to put the belly wrap under the side skin, but that would complicate the build process...that = $$$$$. Unless you have another compelling reason to remove the rub rail, I would remove what sealer is exposed, clean it well, tape it off, and use ParrBond to seal it. A very thin bead. Some like Vulkem better, but I like the clean look of ParrBond and I think it lasts longer, in that application.

[nm1oqrz]

Hello fellow Airstreamers. When I had a leak in my 1988 25" Excella I took the road side rub lower rail off and found just what youall found. I thought this odd for the reason of water infultration, like putting you shiplap siding on your house starting from the roof line working towards the ground.
While I had the rail removed and before I put it back on I put the belly pan aluminum under the side skin where I think it belongs. I still caulked the seam before I put the rail back in place.
Happy camping nm1oqrz

[Minno]

We left insulation out of the under floor area when we redid ours. We put floating engineered cork flooring in the trailer and decided we didn't need insulation underneath. We tucked the side wraps under the skins, but had to put the banana wraps over due to the work involved. We vulkemed it all really well. We also left spots for water to drain out from the lower side wraps and belly pan since we didn't make them watertight.

Kay

[Vicki A.]

Funny thing, I just pulled my back rub rail off and found the same thing. Why in the world do you build the bottom of the ship upside down?! This section needs attention with the wrap anyway, but I sure will be sealing ALL of the rail before it goes back out in the rain!

[Splitrock]

The step release slot on my trailer is a feature I refer to as the step release water intake port. I had to install a drain system below it.

[wahoonc]

I believe on the early trailers 50's and possibly some 60's the wraps did go under the skins, but I suspect in the name of production efficiency it is quicker and easier and cheaper to put them over the skins.

I haven't gotten around to getting rid of the pink insulation yet, but that will be the next major project after the tank area rebuild.

Aaron