Insulation, Radiant and Vapor Barriers - Under floor insulation?

This question has probably been asked before but bare with me...

We are planning a 22' x 32' addition to our existing home. THe floor will be concrete with ceramic tile over. We live in central Wisconsin where winters get a bit on the chilly side. Insulation under the floor will be a "must have". The room will be exposed to what ever sun we get during the winter months. Lots of windows providing direct sunlight.

What is the recommended insulation (and other needs) to put under the concrete floor? The subsoil here is 100% sand.

Normally you use 1" of pink insulation. You can use more if you want.

Greetings,

Check fifoil.com they have a bubble radiant barrier (RB) that has a RB between two bubble layers. It act as a vapor barrier and insulation.

I would also recommend RB for the ceil's and walls. With RB you will probably not have to increase the furnace and a/c size.

Thank you for considering my opinion.

Wisconsincraft; at your latitude i would think that 2 or 3 inches would be the min. beneath your slab. you might be able to place the thicker material around the perimeter of the slab while using thinner material in the center. aprox.20 years ago the Univ. of Minn. did a study on earth sheltered houses,great info.just what you need. use extruded polystrene , not bead board which in an inferior product and not waterproof. Dow makes extruded poly. in in a t/g config. which makes it easier to install and stay in place. be sure to use a vapor barrier beneath in insulation.