I had a very similar problem 2 years ago. The fireplace brick was unpainted concrete brick and very stained with 30+ years of soot. Cleaning didn't make a difference. Using a gray-blue semi-gloss base paint, one quart of clear glaze and 3 different colors of sample latex paint pots (burgundy, tumbleweed beige and desert brown/yellow), my large ugly fireplace was transformed into faux brick that looks better than I ever thought possible. The ratio for mixing the glaze was based upon the size of the paint, the intensity of the color desired and the amount needed. The entire fireplace was painted, except my black slate hearth top, with plenty of clear glaze left over for other projects. Using half a sea sponge, the beige glaze mix went on first. Then the burgundy, and finally the brown/yellow. The burgundy was the key for the faux finish- some areas are more intensely mottled because my initial application of the color left clear edges of sponge bubbles. When the final color was applied, the translucent effect over the burgundy created a wonderful stone-like finish. I had never sponge painted before nor used clear glaze. My base paint was a mixture of paint leftovers with a bit of acrylic tint added to darken. I figured that the whole thing could be painted over if it was hideous! Admittedly, at one point my son said, "Mom, are you trying to lower your house taxes?!?" Now, he freely states that the fireplace is the best part of the room. I wish you success! Redbugsullivan "I can, I will and I do!"

I used regular latex paint and a local brand clear glaze. In all of the research done prior to the painting, the primer remained the key to a good product. Let me tell you, the brick sucks the primer right up! My mortar was nasty so paint was my only solution. My paint job is a breeze to vacuum clean and stands up to heat and scrubbing. One gal I know just sponge painted with glaze on her fireplace bricks to lighten up the space. Worked great! Redbugsullivan "I can, I will and I do!"