Duct board as insulation?

[Bigduke6]

I have a 15 pass 2wd e350. Trying to figure out best insulation to use. I'm thinking about using duct board glued to the back side of the finish panels, foil side out. May have to leave some voids at the ribs, etc. Was thinking of reflectix glued to the ext walls with fiberglass mats in between but the radiant needs airspace to work right, correct? Maybe reflectix on ext, then duct board
on panels. Talk me into something different if you have better ideas. What about rigid foil faced urethane foam on the floor? Will that need plywood over the top? Also thinking of cutting flow from rear heater core, I think it is always hot. I live in south Texas so keeping the cold in and heat out
is the focus.

[teeots]

I have stalled out at this same phase.

I will say that you are correct about the reflectix- 0 claimed r value. It must have airspace on reflecting side in order to work properly.

[Bigduke6]

Bought a roll of reflectix yesterday. Found a roll of r-13 in the attic. Pulled all of the plastic trim from the rear of the van and put fiberglass between the two layers of sheetmetal below the windows on the pass. side,then glued on reflectix w spray contact cement(don't attempt to be cheap and buy anything lessthan 3M super 77-lesson learned-again). Drivers side got only reflectix because the intake air for the rear ac uses the space between the sheet metal as a plenum. Built a platform for the couch/ bed with 14" tall storage underneath-one side for windsurf gear- the other for everything else. Lots more to do...

[luked]

Originally Posted by Bigduke6

Bought a roll of reflectix yesterday. Found a roll of r-13 in the attic. Pulled all of the plastic trim from the rear of the van and put fiberglass between the two layers of sheetmetal below the windows on the pass. side,then glued on reflectix w spray contact cement(don't attempt to be cheap and buy anything lessthan 3M super 77-lesson learned-again). Drivers side got only reflectix because the intake air for the rear ac uses the space between the sheet metal as a plenum. Built a platform for the couch/ bed with 14" tall storage underneath-one side for windsurf gear- the other for everything else. Lots more to do...

Pics?