Insulating around brick chimney and fireplace

[PeoplesElbow]

I have a room behind my garage that is always cold, I always chalked it up to the fact that room has a sliding glass door on one side, a door to the garage on the other and a fireplace on the wall between them. Today after work that room was fairly dark but the sun was out pretty strongly and i could see sun around the fireplace via small gaps between the paneling and the brick fireplace through past the outside siding.

I am guessing that there is no insulation in the first cavity up against the fireplace but i wish to seal the air from getting in. There is a really poor caulking job with this awful hard caulk that looks like someone put it on with a spatula on the outside of the siding (35 year old house).

Does anyone have any good ideas how I can insulate/seal this wall that will still be safe and to code? I don't ever plan on using the fireplace for anything other that decoration (fake logs and fire) but I don't want to have to undoo whatever I do incase I ever decide to sell the house. I am planning on re-panneling the room some time so the paneling on the inside will be down to do whatever I need to.

 

[Wesley02]

Try using the seal in a can. Polyurethane expanding foam works very well. After application and drying you can trim the excess that expands out of the crack or void.

 

[Freefaller]

I have a room behind my garage that is always cold, I always chalked it up to the fact that room has a sliding glass door on one side, a door to the garage on the other and a fireplace on the wall between them. Today after work that room was fairly dark but the sun was out pretty strongly and i could see sun around the fireplace via small gaps between the paneling and the brick fireplace through past the outside siding.

I am guessing that there is no insulation in the first cavity up against the fireplace but i wish to seal the air from getting in. There is a really poor caulking job with this awful hard caulk that looks like someone put it on with a spatula on the outside of the siding (35 year old house).

Does anyone have any good ideas how I can insulate/seal this wall that will still be safe and to code? I don't ever plan on using the fireplace for anything other that decoration (fake logs and fire) but I don't want to have to undoo whatever I do incase I ever decide to sell the house. I am planning on re-paneling the room some time so the paneling on the inside will be down to do whatever I need to.

If you have access to the chase when you remove the paneling, you can insulate the walls of the chase. Use either Unfaced fiberglass or unfaced Rockwool batts. Neither of these unfaced products will burn. The Rockwool has a much higher melting point than the unfaced fiberglass but either is okay to use. DO NOT USE insulation with a paper face on it. That is flammable and should never be used within a fireplace chase. Unfaced fiberglass is probably easier to find at any Lowes, Home Depot, or other Home Improvement stores.

As far as sealing the cracks, use of an expanding foam is a good idea. Just make sure you use one that is fire rated. Not all of them are. An easy way to tell is that the fire rated foams are either orange or red in color.