You need to check your local code. Typically you are not allowed to have any combustible material within 12" of the firebox opening. Sometimes it is 8" or other distance depending upon how much it sticks out from the face (this is for safety reasons!). It will be spelled out pretty specifically in your local code. You can't use furring strips or tape within this distance, cement board is okay. If you want it to look like the adjoining drywall, I would suggest using either cement board or mortar over the brick and then coating it with a smooth stucco or plaster coat to bring it to the level of the adjoining drywall.

You can do it the way you suggest although it may be difficult to attach the plywood (near the firebox opening you can use cement board which meets the code requirements for non-combusitble materials). However, I would suggest that you use mortar, and trowel it on in a sufficient quantity so that it fills up the irregularities and mortar joints and you end up with a reasonably smooth surface. You may have to do it in two coats - first partially filling in the recesses and then a finish coat - the reason is that otherwise a thick coat may sag before it dries. Then you will end up with a surface that is perfect for adhering stone or ceramic tiles to (and it won't stick out into the room as far as a plywood overlay), or even dry wall if you use lead or plastic anchors. This assumes that the existing stone has not been coated with something that will cause the mortar not to stick. If it has, you can use fortified thinset mortar, although it is messier to work with. Hope this helps. Also, since it's 15 feet high you will need a sturdy ladder or even scaffolding (cheap to rent) since the mortar is heavy and you need leverage to apply it.

drystonemason - thanks for the offer! I wish you lived in Colorado. My husband and I have a 70's wall o' brick. Really, the entire back wall of our den is covered in blond brick and the sides have custom built (70's style) cabinetry over the brick. We are planning to rip the cabinets out but our question is, what is the best way to reface this much brick? We plan to put travertine tile below the mantel to break up the look but on the rest of the wall, from what we have read, we have a few options. 1) Use a lime based plaster (not drywall compound) to fill in grout lines and eventually build up and smooth out to a rough, toweled on surface 2) Use mortar and stucco to achieve the same look. 3) Using drywall we can either frame out the whole wall and start over or use liquid nails (a lot of it) to put sheetrock on the areas that are not tiled. Hoping you might have some suggestions on what the easiest route would be considering it IS a whole wall. I will see if I can get a picture to insert which might be helpful.

No, DH is dear husband (who wasn't feeling too fondly toward me during this project!). Our brick was fairly smooth and we used PeelAway 1 (can buy at Sherwin Williams or B. Moore at about $30 per tub - 2 1/2 tubs). Apply it in workable sized areas of the brick with their spatula, cover with their paper (if you run out of their paper use Saran wrap). Let it sit for the full 24 hrs recommended - do not scrimp on time. Rinse off as instructed. In some spots we had to do this twice. We found then that we needed to do a bit more paint removal so got some Ace Hardware concrete cleaner - white plastic bottle with green lettering. Applied and cleaned that off by scrubbing with a plastic bristled brush. Those steps took about 97% of the paint off. The last few % we covered up. Tools used - 1" and 3" metal putty knives, a paint scraping kit with changeable heads from Home Depot, old toothbrushes, other brushes and a dental pick. Absolutely protect your floors with plastic if they are hardwood - the Peelaway will damage the floor finish. Have rolls and rolls of paper towel handy -you'll use them. At that point, we could still some some residue (ivory, coral and pale green paints had been used). So then we used a 50/50 mixture of boiled linseed oil and mineral spirits and wiped that on with rags. That removed (or hid) all traces of the residue and absolutely made the brick's original chocolate brown color pop. I mentioned we couldn't get the last bits off. To cover the bits, we used a combination of 2 things - crayola crayons in the color of our brick for those bricks away from the heat and a tiny paint brush and oil paints to dot on color. It turned out beautifully. Our fire place was 9' high and about 7' wide. Working at a leisurely pace - it took about 2 months in the winter. Would I do it again - yes! Would my husband - no way - although he was very impressed with how it turned out.