Metal over Foam ....

[GPW]

What about putting Metal on top of the foam ... Especially for places like the roof .... It would seem that the metal would expand and contract and the foam would follow it , Unlike metal over plywood (which also Rots ) Good place to consider first is the “rock guard” area ...
Naturally we would need “hard points” for attachment ...

After Isaac , and the roof repairs , we’re left with a few hundred feet of nice R panel .... seeing the photo below was a “salvage” inspiration

[swampjeep]

I like the idea, would you do anything to make the foam conform to the ripples?

[GPW]

... maybe some spray foam in between ??? Although I do have some interesting self expanding foam tape . also leftover ... seals the R panel ... AST Hi-Acrylic by EMSEAL

[aggie79]

In that photo I believe the r-panel is a decorative finish. The real roof is underneath.

The biggest problem with the r-panel other than weight is how do you seal the edges along the corrugations?

[starleen2]

metal over foam - hard points for attachments - you are just one step away from a foam sandwiched wall or roof
The way I see it, the advantage of foamies is the ability to build quickly, light weight, and ease of construction. adding more "outside" elements means something more complex even if "thrifty"

[GPW]

It was just a thought .... It does add more complexity ...

[atahoekid]

I had thought of using aluminum as a skin. I even talked to a person at GG, who thought it would work well as the adhesive. She suggested a "paper thin" film then assemble and weight until cured.

Adding a aluminum skin might not be "thrifty" for a foamie, but we've never really followed rules too well anyway, or we wouldn't be here.

[Shadow Catcher]

Using stress panel construction light weight very strong panels can be made. As an example aluminum outer skin bonded with 3M VHB tape to an aluminum tube frame and an internal skin. VHB tape is visco elastic and some movement is possible. CR has stress panel and when I cut the 4" holes for the AC ducts the Filon outer skin and Luann inner skin attached to the EPS came out as a single plug.

[Wobbly Wheels]

If you're using flat aluminum rather than corrugated, a polysulfide adhesive might be the best bet. It absorbs flex, especially the thermal flex of aluminum outdoors. It's what's used to hold hardware and wood decks on boats, so it'll probably withstand anything we can throw at it. Last winter, I did a refit on a 48' sailboat that included replacing the teak decks. I had two guys working for two weeks to strip the old wood off. They tried everything and found brute force was the only reliable method: a hammer beating on a thin blade (heavy putty knives).
That was specifically because it WAS able to flex and give: you couldn't pry it, you couldn't cut it, etc.

I don't know what the original builder used in 1988 and we used epoxy, but I'd certainly try using Sika LOT291. It comes in caulking tubes and I'd spread it with a notched trowel and weight it evenly: bricks on ply, vac, hydro, etc.

I think the trick would be to find an adhesive that would tolerate the difference in thermal expansion between foam and aluminum. Sika works on polycarbonate, which is FAR more problematic that way than aluminum.

JMHO though, haven't tried it.

[GPW]

Being mostly air, it seems the foam would expand and contract with the aluminum ... just guessing ..

[Wobbly Wheels]

Being mostly air, it seems the foam would expand and contract with the aluminum ... just guessing ..

The foam itself (polystyrene) is stable though - more like pumice than a sponge. If it contracted in the cold it wouldn't work for insulation.

[crumbruiser]

Since totalling out my PT Cruiser and buying the big gashog, I've been puting some thought in the rippled steel for a roof. Weight is no longer an issue. I think expanding foam for adhesion and filling the gaps, plus bolts going through into the roof "truss", add some silicon to all of the edges and joints, I think it would work out.
The picture of the old rusty TD is partly what got me started on this sight and my build. I LOVE that trailer!
Frank

[mikeschn]

So you're thinking about a larger version of this?



Mike...

[GPW]

It does have a certain RUSTic charm eh ??? Looks like some new rims too ... The old wire wheels were Nice ...

[ARKPAT]

Well my Steel over Polyfoam are insulated door panels. Note that No framing except at the doors ( will be replaces by steel angle soon ) that have a wood frame. All this box was sawn with a circular power saw / 24" steel square and screwed together with 1/2" self-tapping screws in about 8 hours one Sunday afternoon before work Sunday night =)


This picture above is of the back hatch door opening .... all cuts are scarfed cut / gorollia Glued / screwed together joints ....... well it is not a looking purdy; but VERY STRONG construction ) I can with a friends STAND on TOP OF THE TRAILER TOP and it will hold us all up Even nicer ... it has 50,000 miles on it sence I built it and the only rust is the rust on the panel you see that was on it when I bought the panels ( that rusty panel is still looks the same ---- maybe some day I will paint it


Pat