Is double bubble insulation an effective vapor barrier?

[NP Carling26]

So, I received what I believe to be a pretty good quote from Fisher Brothers Builders for a 30x60x16. And I want to have atleast some form of insulation is this building. This quote includes double bubble insulation in the roof and walls for a pretty good price. So my question is, will this serve as an effective vapor barrier? And if down the road I frame out the walls, how hard will it be to insulate with regular fiberglass, as I kind of want to do. If anyone has any pictures of how their double bubble is installed, or any experiences, that would be great.

A picture of the quote, for anyone who is interested:

 

[FFRKing]

I'm looking at building a 30x50x12 this summer and have also been wondering the same thing about the bubble insulation.
I have talked with a couple of people and both agree that the insulating factor when trying to heat the building is terrible. My neighbor claims that it works great in the summer reflecting the heat. He say that the inside of the building will stay 20-30 degrees cooler when it is 100 outside. As the sun goes down, he closes the overhead doors to keep the sun from shining into the building and heating things up.
I have a quote for a 30x50x12, 2-10x10 insulated overhead doors, 2 windows, walk door, bubble insulation, with concrete for $16,800. No overhang.

Chris

 

[anthony666]

read this fellas

http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/29497/The-Foil-Faced-Bubble-Wrap-Sham-Understanding-Radiant-Barriers

 

[spotco2]

If installed properly it works pretty well as a radiant barrier but it's not really a vapor barrier. If it's pulled tight against the panels without an air gap between them you won't see much difference with it.

You can easily insulate with fiberglass over it.

 

[TractorJeff]

If I was to staple this to the rafters on my Porch, it would have an air pocket of the rafter spacing. Then the foil would reduce the heat gain on the porch.
Correct?

 

[anthony666]

correctamundo

i use it when i do in joist radiant .. staple it across the bottom of the joists so there's an air pocket and it reflects the heat up