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Here is what I am thinking about for my Ford E350 cargo van insulation.

Walls: 1" polyiso*, 1/2" spacers to create dead air space, coroplast finish skin. Can I ignore what air spaces would be behind that concoction -- none where there's framing, a little where there's indentations and a lot between the outer skin and inner framing and aren't there drip holes at the bottom here anyway?

*Is the polyiso reflective on both sides and if not, did you make a choice which way to face it for it to do one job more than another -- reflect the sun's heat away or reflect inside heat back when it's cold? Or maybe add tin foil to the 2nd side so it could do both?

Floor: Fill between ribs with flooring underlayment strips, 1/2" EPS, flooring underlayment, laminate because I have some.

Roof: Nothing - it's an insulated hi-top.

Thanks! Sassy
Sassy, I think that is a very good plan and no modifications needed. Smile

The air space between the wall and the polyiso is a good thing, no harm done except the loss of interior space. Coroplast seems like a great choice for paneling.

The polyiso I have only has "aluminum" on the one side and since you have an airspace I would put it toward the sheet metal. It will greatly help cool the van in the summer and no loss in the winter. The "aluminum" is very conductive to heat so it has no insulation value, only reflective value. The other side of the polyiso has a vapor barrier on it so tha is a good thing on the inside.

Floor and walls sound great! I give you an A++ Big Grin
Thanks, Bob, I appreciate the feedback. Now I'm researching electrical, to see what all I want to do that may need doing before insulating.

I don't think you all understand insulation and how it works. The "shiny" side on many insulations is reflective mylar or a thin layer of reflective aluminum. Put the shiny side facing AWAY from your living space side. The dead air space is needed between the exterior skin and the heat barrier. When there are no space constraints (like on a house) ideally you would use 3/4" space. In mobile applications with space constraints (like in our residential vehicles) 1/4" should provide a usable space. A sheet of either tiny or LARGE bubble wrap (buy by the box or roll in packing supplies) or even (more expensive) Coroplast (corrugated plastic). Using the physical spacer will maintain the dead air space.

From the outside in: Van exterior skin - DEAD AIR SPACE - rigid insulation - wall covering

From the outside in: Van exterior skin - DEAD AIR SPACE - radiant barrier - rigid insulation - wall covering
Well, the way I see it, the reflective layer should be on the side you want radiant energy reflected back to. If staying warm is the main criterion, then have it facing inward with the dead air space in the inside wall. If, on the other hand, you're more concerned with staying cool, then have it facing outward with the dead air space between it and the exterior wall. That's my $ 0.02..spend it wisely. ..Willy.
@compassrose, you and I are saying the same thing and I agree with you 100%.

@Willy, reflective material only works with an air space so to put it towards the interior means you must NOT put up an interior paneling or you must put up an air space between it and the paneling.

I think it is better to put it toward the sheet metal to help keep out the summer heat. If you are in a place where heat isn't an issue than putting it on the inside would be good. There aren't many places like that in the country.

It's much easier to add warmth to a van than to remove heat!!!
That's basically what I'm saying, though maybe wasn't too clear with my explanation. Basically, the side you want the heat reflected back from is the one with the air gap (dead air space). ..Willy.
Maybe it is a non-concern to enhance interior heat retention, in which case I may forget about it. I just like the idea of killing two heat/cold issues with one, ermmm, sandwich.

I vascillated about adding that layer of bubble wrap first on the outside, compassrose, so thanks for that opinion. You've confirmed that all the spacing that exists between the inner and outer skins of the van will not serve as the needed dead air space since it's not really sealed.