Replacing slate with stone on a fireplace

Debbiesue

I am planning a project for my home and need advise. I have a zero clearnce type insert fireplace in my home which burns wood. It has a very 80s appearance to it as the builder installed black slate on the outside of the FP.
I want to remove the slate and wood trim, and replace it with manufactured stone (The stone is an M Rock brown fieldstone) What I have in mind is to replace the slate with concrete backer board firmly attached to the wall with screws and washers. I also plan to enlarge the amount of the wall covered with stone by carrying my concrete backer board out over the exsisting sheet rock.
Am I creating a hazard or any problems by doing this? I do not plan to disturb the basic installation of the fireplace in any way. It would seem the additional stone should actually be safer.

Installation of the stone will be with conventional mortar and I plan to grout it with tan mortar to blend with the stone.

Is this a good method or do any of you have reccomendations?

davethebuilder

I assume you will be only fitting new stone to the front of the fireplace and not in the firebox?

Sheetrock or plasterboard is not a sufficient fireplace material even the fire rated board. Suggest you cut out all the sheetrock in the area that you want to lay the stone.

Install FC sheeting (Fibre cement) which is compressed cement sheeting. Glue and screw this FC to your stud walls and seal all gaps with a fire rated mastic or sealant.

Clad your stone directlt to the FC sheeting..

itsreallyconc

not having f'd w/fireplaces in yrs, i do recall code saying no combustible mtls w/i 3' of the fire,,, even tho we use sheetrock for firewalls, its doesn't meet fireproof standards, only fire-resist,,, hopefully, if this is incorrect, anyone smarter'n than me'll call me out & post the correction

the only thing i'd do differently than dave's placing expanded metal mesh over the sheetrock,,, as w/any stone wall, the weight's supported from below ( floor joists )

Debbiesue

So far everyones comments are similar ot my thoughts. I may leave the slate in place and drill it to support the concrete backer board rather than remove it. As to removing the present sheet rock, it is outside the area where it should matter...The slate extends out 10 inches on either side of the opening and up to the mantle so I am going to screw the concrete backer over the sheet rock. With the screws going into the studs of course.
I;m just doing outside the fireplace, I'm not extending inside. The exsisting firebick suits me just fine and I do not think manufactured stone would take the heat of the firebox anyway.

Thank you all for your comments. If anyone else has ideas, please post them soon as I plan to start work on this project after next weekend.

Termite

The International Residential Code requires the following clearances to combustibles for woodburning fireplaces (I'm summarizing):

• Min 12" clearance from top of firebox opening to combustibles
• Min 6" clearance from sides of firebox opening to combustibles
  • Nothing combustible within 6" at sides
  • Combustibles cannot project more than 1/8" for each inch of distance away from the firebox sides up to 12". For example, at 8" from the firebox a piece of wood trim cannot project more than 1/4". 9" is 3/8", etc.
  • At 12" away any size or configuration of combustibles is allowed
• If firebox opening is <6 square feet:
  • hearth must extend 16" from front of firebox
• If firebox opening is 6 square feet or greater:
  • hearth must extend 20: from front of firebox
• Hearth has to have 2" of solid masonry (not tiles over wonderboard and plywood.
• hearth extensions must extend 12" from each side of firebox

Personally I like the 3' idea more!!! That's a lot safer.