http://www.energyblock.com/order.php

Posting this as an alternative. This is such a pain in the USA. I'm getting within a couple weeks of electrical so need to start thinking more about this now and decide what to do. Not sure where you guys live but the vapor hats won't work for me. The metal conduit boxes and pipe will come in one end, go out the other, and most of these will be mostly removed. I am considering not even bothering with it because of the amount of conduit going into/out of the each box. The electrician will run daisy chained from one end to the next so what might be better is spraying the outside of the box (or the inside before he pulls wire) with a rubberized can spray? Anyone think of that, or do that before?

"so what might be better is spraying the outside of the box (or the inside before he pulls wire) with a rubberized can spray? Anyone think of that, or do that before?"

I'm thinking about like truckbed liner. This seems like an economical solution. Once the boxes are in and conduit is run, before insulation, shake the can and spray it from the back side from the top and bottom to get a coating over the box. What do you guys think?