Alu-clad without plywood

[grantstew8]

I'm ripping an old donor caravan to bits and noticed that they did not use an outer layer of ply. The Aluminium is also not attached to the roof spars. The caravan is 30 years old so the adhesive may have failed but let me tell you, the other adhesive is still sticking like the legendary to a blanket..... The walls in the caravan are composite, like a SIPS panel. 1/8" ply as the inside skin, 3/4" polystyrene and alu-clad all bonded together.
My plan was to use ply both inside and out and then clad the outside with Aluminium.

Given this discovery I wanted to ask, before I fell into a deep hole, if this was a viable option to use aluminuim as an external skin without using ply below it.

The photos of the caravan are not great and I've ripped off the mdf and removed the glass wool insulation in the roof (these are photos of roof spars)



You can see the aluminium is not attached to the roof spar. The polystyrene wall is in background with some ripped ply.

I've more photos of the caravan in my gallery http://www.tnttt.com/gallery/album.php?album_id=3044

[aggie79]

The technique you mention of appying exterior aluminum sheeting to the framing and not to a plywood underlayment has been used. The examples I recall did not glue or adhere the aluminum. It was held in place mechanically by aluminum trim at the edges and around openings.

Unfortunately, I can't recall the names of specific individuals using this technique in their builds. I do know that the former Trailer Works company - apparently no longer in business - built their Retro Traveler line of teardrop and tiny travel trailers this way. On this forum, the owner used the avatar "TrailerWorks". This is a link to a trailer build that he posted on this forum:

http://www.tnttt.com/viewtopic.php?p=377215#p377215

Unfortunately, there are no pictures in the gallery that shows this technique.

[Lgboro]

I borrowed this idea from "Madjack" who was a previously active here and his Alligator Tear. My 4x9 was built this way over 3/4 inch by 1 1/2 inch cedar framing and filled with blue foam insulation. My roof is covered in .040 and the sides with .032 aluminum. I logged in over 18,000 miles in the last year and haven't had any structural or other problems yet . When I build my planned standy I intend on using the same method unless I go with aluminum framing. When the 1/8 inch cedar strips were glued in the tear became mega strong.









ps..My aluminum is floated and is held in place by the trim, windows and doors.

[grantstew8]

Fantastic info and photos. I'm going down this route