insulating brick fireplace?

[peter]

I have a brick fireplace that is brick both inside and outside (the chimney). It is stone cold to the touch from inside, and is warmer than the wall from the outside. I surmise heat is leaking out of this thing due to air going out the chimney, and also due to moisture condensing in the brick, causing it to conduct heat more (and causing the brick to get even colder, and creating more condensation).

How do you insulate this? I found a lot of windows and floor/ceiling insulations at hardware store, but didn't see any fireplace insulation. Specifically, is there such thing as moisture barrier for the bricks, to prevent them from absorbing moisture? Yet, it has to be "fire-friendly" in case I decide to use the fireplace afterall --meaning it should not burn, smoke, create foul odor, turn into goo when heated. If it vaporizes quietly, that is ok.

[Joseph Meehan]

The short answer is you don't

BTW if air is going up the chimney, you need to add a working damper to stop that. Air going up the chimney would actually warm it since it would be at room temperature.

Moisture condensing would actually warm the brick, it would be moisture evaporating that would cool it.

In any case I would strongly advise you to seek the help of a expert professional before trying any home brew fixes.

[German Jerry]

There is a fireplace insulator called a chimney balloon that is installed usually above the damper and inflated into place. This would stop the heat release issue through the chimney flue but I understand you have an issue with heat and cold actually conveting through the brick itself.