Impossible! You will not be able to accomplish what you have described if you are planning to meet code. The thermal mass ( the fireplace and chimney) must be kept at least two inches away from anything. NO insulation 'wrap' No nothin'! Just airspace!
My recomendation would be to build your 'thermal mass' fireplace, then convert to a class "A" mfg chimney. That will meet code, and there are parts available to do it just fine. It may be better to use class "A" all the way down to the firebox and build a 'chase' around the chimney. Your finished fireplace will look terrific, and perform much better than an all masonry fireplace.
That way you get your thermal mass on the interior, and a superior "factory built" chimney to go up thru the attic to the outside. (Class "A" chimney is insulated pipe, lots of different mfg's) Go with somethig like ICC if it is available in your area.
This will likely accomplish your goal with the added benefit of preventing moisture intrusion, a problem we deal with here in the northwest... lots of rain here, over 100 inches annually.
Good luck on your project, sounds like you're doing an awesome home!
HTH, Mark |