'77 Excella 500 31' Off Road Build

[kidjedi]

Originally Posted by HRTKD

When I have to remove the belly material and fiberglass insulation to get to something on the underside of my trailer, I've been using Owens Corning rigid foam to insulate the underside of my trailer. So far, it's worked well.

Not sure what material the Owens Corning is made of, but polyisocyanurate is definitely the way to go (rigid, foil faced, closed-cell foam panel). It has the highest R value of any of the rigid panel insulations, it is very light, and it *will not* hold moisture.

[GPurcell]

Yup I still need to find a solution for insulation on the floor. I love the idea of ease of working on anything under there without the belly pan in the way.

[GPurcell]

Originally Posted by PeterH-Airstreamer

No flack, just wondering about lots of drag and no option for insulation?

Not too worried about drag. The beauty of an airstream is I feel it has a way better drag coefficient than most all other RV's out there. With or without a traditional belly pan.

[HRTKD]

Originally Posted by GPurcell

Yup I still need to find a solution for insulation on the floor. I love the idea of ease of working on anything under there without the belly pan in the way.

If you're creative in how you install the rigid foam, it comes out as easy as it went in.

I was looking at a 40' toy hauler with no underside insulation. Crawling under there for hours on end wasn't going to be a lot of fun. The plan was to hold the insulation in with angle aluminum along the edges and a single aluminum strap across the middle. This would be installed in sections of course. The chance of installing and entire 4'x8' panel at a time wasn't likely to happen.

I think the construction of your trailer frame lends itself to this. At least on the central part of the frame. Rigid foam outside the frame rails would require a slightly different method.

[GPurcell]

Originally Posted by HRTKD

If you're creative in how you install the rigid foam, it comes out as easy as it went in.

I was looking at a 40' toy hauler with no underside insulation. Crawling under there for hours on end wasn't going to be a lot of fun. The plan was to hold the insulation in with angle aluminum along the edges and a single aluminum strap across the middle. This would be installed in sections of course. The chance of installing and entire 4'x8' panel at a time wasn't likely to happen.

I think the construction of your trailer frame lends itself to this. At least on the central part of the frame. Rigid foam outside the frame rails would require a slightly different method.

I'll definitely have to look in to this...

[GPurcell]

Any options that could go inside the trailer - more specifically under whatever flooring I use?

[truckasaurus]

My plan was, and probably still is, to leave the frame cavities insulation free. I've installed the perimeter belly pan to the rails and at some point I'll cut sheets down to cover each cavity. But each sheet section will be joggled with a 2" lip so they can overlap from front to back and each section will be cross braked so they don't make that oil can boom. Above the floor I think I'll use 1/2" cork for insulation and very likely leave it as the finished floor.

I plan to use 3 grey tanks and a DOT LPG tank in the frame cavities so no insulation gives me more room and less headaches.

[GPurcell]

Originally Posted by truckasaurus

My plan was, and probably still is, to leave the frame cavities insulation free. I've installed the perimeter belly pan to the rails and at some point I'll cut sheets down to cover each cavity. But each sheet section will be joggled with a 2" lip so they can overlap from front to back and each section will be cross braked so they don't make that oil can boom. Above the floor I think I'll use 1/2" cork for insulation and very likely leave it as the finished floor.

I plan to use 3 grey tanks and a DOT LPG tank in the frame cavities so no insulation gives me more room and less headaches.

Cool something else to look into. I wonder how well the cork would stand up to dogs coming in and out all the time.

[GPurcell]

Are these what y'all would use to screw down the floor? Or am I missing a better option?

http://odmrv.com/catalog/index.php?m...roducts_id=611

[truckasaurus]

similar I think. With your steel tube wall thickness i'd look for a self tapping floorboard screw that matched the gauge correctly, Fastenal or similar maybe 5/16" diameter.

[GPurcell]

Originally Posted by truckasaurus

similar I think. With your steel tube wall thickness i'd look for a self tapping floorboard screw that matched the gauge correctly, Fastenal or similar maybe 5/16" diameter.

So more along the lines of this?

https://www.fastenal.com/products/details/32535

[truckasaurus]

Yup, exactly

[GPurcell]

Originally Posted by truckasaurus

Yup, exactly

Ordered - thanks for pointing me in the right direction

[GPurcell]

I went ahead and ordered the curved section of c-channel direct for front and rear so I don't have to mess with it as much. I did not realize it would be the double-c setup like down the sides. Kind of annoying.

[Mikebrady62]

GPurcell,

Another and IMO even easier option is the Elco Brand 1-7/16" wing tek screw. The wings makes the hole in your wood slightly bigger so it doesn't burn the point or break the screw trying to thread and drill at the same time. Then the wings break off on contact with metal and self drills the metal.
These have been great for me.

Good Luck!

[GPurcell]

Floor should be cut this weekend. Waiting for my floor screws to be delivered so next weekend maybe... just maybe... I might have a trailer back in one piece.

[GPurcell]

Floor cut to the correct width. I forgot the c-channel at home so didn't mess with the curved sections front and rear

The wheel wells have to be cut out still too. It's still big progress though.





Since the original curved sections were shorter than the rest, I'm thinking of actually taking the access out here at the wheels.





Standing on the floor was a great feeling...

[GPurcell]

Oh and I forgot to grab some pictures of it but prepped the c-channel down the sides of the shell. Removed the remaining bits of old floor and cleaned everything up with a grinder.

[Krek]

My apologies if I missed it but what flooring did you decide on?

[GPurcell]

Originally Posted by Krek

My apologies if I missed it but what flooring did you decide on?

Coosa Bluewater 26 board