Reasons for the solution you chose

Environmental impact Study:

I study the environmental impact for the floor. I compare two materials for the insulation: Cellular Glass and the Polyurethane.

We can see on the graphic that the Cellular Galss release a lot less Carbon Dioxide than the Polyurethane. And the polyurethane has more primary energy than the cellular glass. 

So the Cellular glass is better than the polyurethane because it is better for the environmental impact.