Ren, your previous answer has me scratching my head a little bit. We have two 3-inch vents through the outside wall into the cold room. As per your advice to others, we will run ducting from these to within 6 inches of the floor with a damper to control the air flow. The cold room itself will be 8 by 8 and will mainly serve as a wine cellar. Target temperature is 8 - 10 degrees C. With this additional information, is your previous answer still the way to go?
Answer:
Insulating the ceiling of a cold room that has an occupied portion of the house above it will not do you any favours. When I suggest insulating the ceiling, it is for a cold room that is exterior of the house and there, you need it.