Ironwood Builders ben, put in a mantle! The paint is too light for the smoke and soot, consider a darker covering, either paint or tile or natural stone...slab, veneer or stone tile. I had a similar problem on a fireplace and eliminated it with a sightly lower tile edge. The tile was thinset to a parge coat on the brick and an angle iron wrap was put on the firebox to cover and support the dropped edge. That gave just a bit more roll to the smoke and heat..enough that it solved the problem...it was lucky.

A.J.M. Definitely install a mantle. Definitely veneer over the brick with either natural thin cut stone veneer or cultured stone veneer. Definitely don't think for a second that smoke stains outside the firebox is in any way - alright and can be remedied simply by padding out! Have the chimney inspected/cleaned before you do anything! There is no reason for a properly built and properly maintained chimney to have smoke anywhere but inside the chimney. Here is a photo of a similar situation where I did indeed add natural thin cut stone veneer.

Ironwood Builders AJM. The fireplace I modified was a metal manufactured Heatilator with an inadequate smoke lip and no roll, no damper. The metal frame extends into the firebox an additional 5" to create a secondary smoke lip and roll the heat up the flue. Lucky it worked yes. Masonry fix..not possible. Touch the firebox in California and say goodbye to your woodburner. The chimney was inspected, as I'm sure ben's was, when the house was purchased...part of the home inspection required by the lender and realtor. You are obviously a talented mason, building a proper fireplace is becoming a lost art. Beautiful work. Perhaps you'll take a look at mine too.

A.J.M. Just in case you took my post the wrong way....I would like to take this opportunity to clarify. I was in no way attacking your post or anything, just making sure the guy took the proper steps. You're right about the inspections having to be done by law, however, many years ago, I bought my house and no one said anything about anything and I ended up with a lot of problems that should have been picked up on at the time. And- ughhh, I hate those heatilators!!! I've had to cut so many of those crappy things out of peoples houses over the years, I had nightmares! LOL. Luckily, since they are so old, most have been decommissioned and you don't see them much anymore. Modern day inserts like the ones from Pacific Energy have incredible reburn technology and are self-contained in the sense that they don't have vents popping through the Masonry like those old beasts did. To sum it up, I understand where you're coming from. Not a whole lot of choice with your design, but Bens is an actual fire box. Smoke coming back into the room is most likely caused by obstruction of the damper plate, (or simply a malfunctioning one), blockage within the flue, the smoke shelf filled with crap or the chimney height above the roof line not being high enough. So what I am saying is, I think there is a problem that has not yet been identified and that no matter what you do with the lintel, it needs to be addressed. My 2 cents.

olldbobbi What color hardwoods? If they're light enough, paint the fireplace a dark gray, would be stunning!

Susanna I vote for stone but have the fireplace checked. Have windows been replaced in the house recently to make the house tighter? I would be concerned that there might be a negative air pressure problem causing backdraft of smoke. It happened to mine and wasn't caught on the home inspection because they don't build a fire. You can't tell by looking.

Once you have that investigated, check out Eldorado stone veneers online. They did mine in one afternoon. No mess and people think I had a new fireplace installed. I chose stacked stone but they have all kinds and colors. No...I don't work for them :-)