You might want to point out to Wifey how much money you saved, while at the same time preventing this type of material going to a landfill, an ecological no-no.  Last week I picked up two 1"x2'x8' sheets of extruded foam, for my ongoing house reno project, at a nearby lumberyard, at a cost of $22.00 per sheet.  Where did you say this house was?

   At least I've finally decided to 
not  use extruded foam sheets for my upcoming second-level layout extension!  Sheesh! (Maybe burl walnut, with ivory inlays.

 )
 
Wayne