Originally Posted by Belegedhel
Your existing inner skins are made of aluminum. If you want to replace them, then aluminum is the obvious choice. I have heard also of people replacing their interior skins with thin plywood, and of others creating a wood interior by overlaying the plywood over the existing aluminum skins.
You will find some people of the opinion that the interior skins are "structural," and must be of a certain material in order for the shell to have integrity. I would disagree, citing the fact that many people use their trailers as "aluminum tents" without any interior skins, and no harm comes of it. The interiors are also held in place with relatively scant pop rivets, compared to the bucked rivets that hold the shell together 1 per inch or so.
My biggest concert about replacing the interior skins with anything beside aluminum would be how it will react to changing humidity, heat, and exposure to leaks. I have been in plenty of old neglected trailers, that once had beautiful birch plywood interiors, that have now become stained and warped with age.
Monocoque construction, means a "load bearing shell".
Airstream is actually semi-monocoque, in that the load bearing shell is not 360 degrees around, like metal Aircraft.
The interior shell is just as important as the exterior shell.
Also, many owners do not know that the Airstream frame, does not
support the shell, but the shell indeed, supports the frame.
That's why adding more weight to the rear frame, if not done properly, will cause a rear end separation, even faster.
Ask those that have been there, done that.