No Insulation betwwen floors

[Sam Morris]

This house had a main attic above the second floor which had plenty of insulation, but what I'm concerned about is the 1st floor. There was a space between the first and second floor ceiling. No insulation was present, shouldn't there be insulation between them?? The only thing keeping the heat from escaping is the plywood ceiling.

[Jim Luttrall]

You need insulation at the thermal boundary between the interior and exterior. Typically insulation is not used in the cavity between the ceiling and floor between stories. You might need insulation at the perimeter wall in your photos if that is an outside wall or unconditioned space.

[Fred Weck]

If there is habitable space above and below the space you show in the first 2 photos, that space should be draftstopped into approximately equal areas less than 1000 square feet.