Reducing a Firebox Opening

[Mindsgoing]

How do I install and support 12in x24in tiles “across” a firebox opening? Not over the top of the opening, but literally across the opening?

I tore out the brick veneer & hearth extension from my 100% masonry, site-built fireplace. I left the firebox, chimney flue etc & hope to go back w granite or marble tiles & mount my flat screen TV into a recess above; w or without a mantel, depending on your expertise.

The completed depth needs to be as thin as possible with little heat transfer to the TV area.

The firebox opening was roughly 20’ high but the removal of the brick & angle iron opened it all the way up to the damper. I thought about cutting slots in the firebrick mortar and inserting the original angle iron there to support durock or hardi board and then attach a wire mesh, then a scratch coat of mortar and then my tile but I’m concerned that the expansion and contraction of the angle iron will cause the tiles to crack. Also, I don’t know about heat transfer. I’d love my new flat screen to stay as cool as possible.

Would it be ok to run a concrete backer board from side to side and screwing it into the studs on the sides? & is it necessary to apply the wire mesh, scratch coats etc? Should I use 2 boards?

I know about the codes like the 12” rule and the hearth extension rules but the stopping down of that huge opening has me stumped.

 

[bholler]

Is your smoke chamber lined with either fire brick or vitrified clay? If not you need 8" of solid masonry between the inside of that fireplace and any combustible material. And it looks like you only have one brick or 4" so you will need to put a masonry face back on it unless the chamber is lined which in that case you need a total including the lining of 6".

The other alternative is to parge the chamber with a product like chamber tech which will reduce your clearance if you get enough thickness built up

 

[Mindsgoing]

Thank you bholler . The smoke chamber is fire brick. I really wanted a flat modern look, with a recess for the TV but, research has me thinking I'll need to re-brick and then apply tile over it. (the brick was pulling away from the fireplace anyway so It wasn't too much of a waste of time. )

 

[kennyp2339]

Thank you bholler . The smoke chamber is fire brick. I really wanted a flat modern look, with a recess for the TV but, research has me thinking I'll need to re-brick and then apply tile over it. (the brick was pulling away from the fireplace anyway so It wasn't too much of a waste of time. )

When building the new front add some conduit for electrical in between the last course of brick and plan for a recessed area to mount the tv, also small under kitchen cabinet led lights.