For the pros and/or perfectionests....you guys feel it is worth the extra effort to build up a sub floor to accept 3/4 solid.ie.2by4 sleepers 3/4 ply with polystyrene insulation.Or is there a better way to do this.The reason I ask is that I purchased a bostich MIII stapler to do my living/dining rooms(which I am very happy with)and I would like to use this tool again before I sell it.Also the warmer feet advantage.If it was your own home to do this in,would you still opt for the engineered or go 3/4?Thanks in advance for any replies.

I think that you may have problems with adding that much height (1.5" + 3/4" + 3/4" =3" ). A home needs to be designed for that and personally, I wouldn't want to cutting 3" off the bottoms of all my doors. If you want to nail another floor down, you'll need a wood subfloor. 3/4" CDX plywood will fit the bill nicely and it can be floated, nailed and/or glued over a vapor retarder/barrier. You will need to use shorter staples in the M111 FS (1.5" instead of 2"). Once you have 1.5" of wood installed, I don't think your floors will be "cold". Wood is a good insulator. But if you do not have room for the 1.5", then an engineered floor can be floated or glued direct to the concrete after tests have shown it to be acceptable.