I finished it this afternoon, when I put the 5.2mm" luan down I riveted and it was almost strong enough on its own.
But when I put a lot of weight on it there was some flex, I continued with the 3/4" styro glued in with liquid nails, with the outside edges framed with 3/4 X 3/4 popular, then the top layer of 5.2mm luan was glued.
It is really nice, strong and lite in weight.
The 5.2mm is a little less than 1/4"
I'll get some pic's up ASAP
All the weather surfaces were covered in 1/4" foil bubble insulation.
I'm satisfied the way it came out.
'77 Sovereign Intl 31' CB
WBCCI R2 Rep VAC 11411 Metro NY VP