How to insulate concrete floor (subfloor, laminate, tank, insulating)

[bay]

We have a Playroom on ground floor which is on concrete slab. We plan to raise it up for 4 inches and cover with laminate floor. The township inspector was asking if we are going to do insulation since we are raising the floor. However, the town staff would not tell us how to do it. Our contractor does not know it, either as the space is very limited and cannot do the regular fiberglass insulation like the walls and attic.
I was researching online and only found one article related to it. It suggests to put vapor barrier, then 2 by 4 and use rigid foam insulation bewteen the lumbers, then cover with plywood subfloor and laminate floor. Is it the correct way to do the insulation on the concrete slab?
Another question is that how we keep the tank of spray foam insulation with temp 75 degree in this winter time? We read the production insutruction and it said that you will have to keep the tank to that temp in order to have better performance of the foam.

[K'ledgeBldr]

Yes.
Why do you ask about keep spray foam canister warm/heated when you're using rigid?

Rigid insulating foam comes in standard 4X8 and 4X9 sheets and in various thicknesses.
I've also seen polystyrene used for the same purpose.

[bay]

sorry that I got mixed up. We plan to use spray foam for crawling space. I am just curious how people do spray foam in winter time when the instruction stated the tank has to keep at certain temp.

[VegasGrace]

I'd recommend the 4x8 sheets...the R value differes w/ material and thickness.

Is the spray foam...I'm looking for a spray on insulation that I've seen on HGTV on "Income Property" and this other show where this man fixes other contractors mistakes.

Where do you get it?

[bay]

We just search the internet for spray foam. There are many brands to select. However, they charge shipping.

[Coldjensens]

You can use ICYNENE which is great stuff, but you cannot put it in yourself, you have to hire someone. It takes specialized equipment and a lot of power. They have to make a temporary connection right into your power box.