Our Home is 25 years old and the kitchen overhangs the foundation at the depth of the counter and cupboards (aprox. 30 inches). Every winter we have the same problem, of the floor in front of the cupboards and the cupboards themselves being very cold. I have tried placing rigid insulation on the deck and then pink fiber glass insulation on top of that to fill in the gap and then box it off with rigid again. This does not help.
Answer:
I have a feeling there is cold air infiltration at work here and the only way you'll stop that is with sealants applied strategically to keep the wind from blowing in. That won't do the whole job but at least it will go as far as you'll ever get.
