Energy Usage, Conservation and Weather Stripping - cold air coming in where brick fireplace meets wall?

Hi all,

Can someone tell me the best way to eliminate cold air coming in from all 3 sides (the top and 2 sides)of my masonry fireplace where it meets the wall. The cold air is coming in where the mantel and the 2 brick sides of the fireplace meet the wall. I removed the mantel so that I could get a good look at everything and I found that the cold air is coming from several areas, basically anywhere there is a slight opening, i.e. where brick meets wall, through mortor holes in bricks, where mortor is cracked etc. On the 2 sides it coming is where the brick meets the wall. My thoughts were to just caulk the sides and the top, but now I'm wondering if that is going to be good enough. Should I stick some insulation into the cracks instead of caulking or should I do both or is just caulking all that is needed. Or should I be doing something entirely difffernt. I like the fix problems the right way the first time. Any advice is appreciated.
Thank you

Maybe try some of the "Great Stuff" expanding foam. If it is just a crack maybe open the crack with a 1/4" drill bit. Insert tube of the can and go to town. You might want to get the window and door type so you don't burst the wall. ;)

Hi Mross, typically a fireplace on an outside wall has to have a 2" clearance from any combustible materials, ie wood. On an interior wall same clearance but your exposure to cold is only through the attic. Once again, the typical builder solution is to stuff some fiberglass into the space and cover the gap with siding outside and sheetrock inside. But the fiberglass is noted for not stopping air flow, thus the leakage you are feeling. To complicate locating that gap, the brick facing on the inside often overlaps the sheetrock as much as is necessary to achieve the inside desired width.

The proper way to close the gap is metal flashing sealed to the chimney with a fire rated caulk. Obviously getting back in there would be a major project. I can't recommend the foam, but if you use it be sure to use the fire rated version.

Bud

thank you bud9051 and Tolyn for your responses.

This is what I did. I removed the mantle and then filled any open spaces in the brick and mortor and between the brick and the wall (that were wide enough) with pink fiberglass insulation, the rest (that weren't big enough to get insulation into) I caulked. Then I caulked the sides where the brick and wall meet. Then, before I put the mantel back on, I placed a blanket of 1/2" thick fiberglass insulation over the entire top of the fireplace (where the mantel normally sits) and then put the mantel back on, which sandwiched the fiberglass blanket between the fireplace brick top and the mantle. And then finally, I caulked all around the mantel and the wall. And wallah, no more cold air. What do you think. Any problems with the way I did it? As I said, it stopped the cold air from coming thru. Comments welcome, Thank you

Considering the alternative of tearing everything apart and starting over, you probably did the next best thing, especially if it stopped the immediate draft. What is missing is keeping the cold out of the walls which would show up with an infrared scan. Just keep that in mind if you ever attack that area to remodel, but for now you got it :).

Bud