Hello – Hoping to get some advice on how to insulate a Flat Roof on a portion of our home.  Stumbled on this site as I was trying to figure out how to insulate a roof that was recently repaired (it was leaking).  Wish I had found you all earlier, but from reading other forum posts, here’s some pertinent info:

Project:  Small Bathroom Ceiling (6′ x 4′) on a previously built extention (they closed off a portion of an old exterior deck) on 100 year old home
Area:  We’re in New York, Zone 4
The Roof:  EPDM Flat Roof with 1/2″ of ISOGard paneling (Unvented).  
The Cavity / Space:  2″x 10″ Joists with ~3″ Cavity between the top of the joists and the bottom of the plywood (roof).  

We have the bathroom ceiling ripped out as the roof was previously leaking.  We had a roofer come in and repair the roof  (I would have done this, but I know nothing about flat roofs so left it to a contractor), and now I’m getting ready to replace the ceiling.  The room is cold as hell during the winter, so trying to do anything to help retain some heat.  

I would love to bring this up to the NYS Code of R30+ for the roof (and it would be amazing to hit the R49 mark you all mention here), but from from reading the responses on this forum to other posts and reading a few of the articles you have posted in them, I’m not sure I can due to the 1/2″ of ISOGardthe contractor used (Sounds like he should have, at the minimum, used 3″ of ISOGard?).  

Anything I can do to properly insulate this roof at this point?