Framing for stone veneer around FP

[RickE]

I was hoping to sanity check my plans with the gurus on the forums! I'm planning to do a stone veneer around my zero clearance FP. My plan is to buildout the wall just a bit, by using 2x4s on face to run horizontally across the existing vertical studs (I'll go over the existing sheetock. Then I will lay 1/2" plywood over the studs (also horizontally) from ceiling to floor. I am going to replace the one wood stud with a metal stud where the top of the zero clearance fp is and use wonderboard or some backerboard instead of plywood for the heat concern. Then obvioulsy I'll put down the tar paper and lathe, scratch and set the stone. Does this sound ok so far? I also have another question that I'm hoping someone can help me with:

To maintain the symmetry of equal spacing of the veneer on both sides of the FP, The layout falls just a bit past one of the vertical studs in the framing. One the right side of the fp, i'm right on a stud. On the left side, however, I run past a stud by about 6". I see two options - one is to remove the sheetrock and put in a new vertical stud to ensure I am hitting against a stud (a lot more work but more structurally sound) or 2 - since I am running the buildout studs horizontally, I will have bearing across about 6 other studs and was wondering if I can use an anchor bolt (and maybe a dab of liquid nails) to tie into the sheetrock. Do you think hanging over by 6" and missing the stud on the left side is a big problem if I tie in with an anchor bold and given that the whole buildout should be tied together by the existing studs both horizontal and vertical, as well as the plywood, scratch coat, etc? I'm feeling like putting the stud in may be overkill but I am not sure. I'm sure this is a fairly common problem around fireplaces? Any thoughts?

PS - This finished dimensions of the veneer will be 90"w x 12' tall (its a 12' wall in a great room)

Thanks!

Rick

 

[begreen]

What ZC fireplace is this? The reason I ask is to read the documentation on clearances to combustibles. That should be your guide.

Your process sounds correct, just be sure that there are no gotchas for clearances, especially with highly flammable tar paper involved. If there are clearance concerns, ask if metal studs with cement board (instead of plywood) would also work.

 

[ROVERT]

Look into it, but you should be able to use just cement board. Scratch coat that and then install your stone veneer. I don't think you need plywood/tar paper/lath to do this. That sounds like the recipe for an exterior installation. I believe you can also just put up cement board and use thinset mortar to install your stone veneer (if it is cement based and not real stone) without using a scratch coat or lath.

I'm not a pro in this area, but I was considering stone veneer for the project I am currently working on and I'm pretty sure cement board is all you need.

Even if the fireplace allows you to install combustibles, I wouldn't. I would use metal studs and and cement board, keeping everything non-combustible. That will keep your clearances down if you ever decide to install something else in the space.

I think you're worrying too much about the stud over hang. You should be spanning at least five or six studs. Once you put a sheet of something on that (plywood, cement board, drywall, etc.) it is going to get pretty rigid, even with a little over hang. If it makes you feel better a toggle bolt in each overhanging furring strip could be used.

I would probably frame a normal wall (vertical studs) with metal studs up against the dry wall.

 

[Jags]

If you do use just cement board a common practice is to scratch coat it then use a scarifier to create the lines or "keys" that the buttered stones will stick to. It is acceptable to go directly to any cementious substrate, but the keys will give you better holding power.

And as BG said - Clearance to combustibles is really your only concern. Your basic plan for the stone is acceptable.

 

[RickE]

Thanks for the responses everyone. The fireplace is a Majestic MR42A. I cannot seem to find a manual anywhere online. This unit is interesting in that it has no air vent on top or bottom, just solid metal panels all the way around. Because of this, I was planning to put in a raised hearth of cinderblock then limestone. Was going to finish with the same stone as above.. Since there is no air vent, I dont think i'd be blocking anything by coming up a bit (i'd come as high as about 1.5 inches below the door bottom. Since I am using all non-combustibles for the hearth base I cant imagine the clearance will be too much of a problem.. Previously there was a 1/2 marble hearth flat on the carpet, so there was about 8" to the floor from the bottom of the doors. I am cutting that down a bit.. Any thoughts? I wish I could just lay the limestone flat but my wife wants the look of a raised hearth.. Thanks

Rick

 

[begreen]

This is an old, contractor grade zc fireplace. You may have a hard time getting a manual for it. I would not decrease the hearth depth at all.It should be increased. Sparks and embers can and will shoot out from some splits when you least expect them to. Having carpet only 8" away sets off red flags for me. In the least, cover it with a fiberglass hearth rug.

 

[RickE]

Thanks, I might have said that wrong, what I meant was height of the hearth. The hearthstone dimensions are 96"Lx20"wx2"deep. So, vertical height of the hearth is being raised off the floor (i said carpet when I meant floor, though carpet does butt up to the hearth after 20" which I think is code). I am going from basically a slab of marble laying on the subfloor (same level as the carpet), to raising it with a 4" cinderblock base to be approx 1.5 inches below the doors. Just wondering if that seemed ok since its all non combustible. I looked at majestics site and saw some of their newer models, all which have air vents and they specify not to block the air vents but since this model has no air vent whatsoever, I was thinking it would be ok to do the lift... Hope that clarifies things, does that make sense?

Thanks again
Rick

 

[begreen]

By the description that sounds ok, thanks for the clarification. If want to post a picture to get a looksee for greater peace of mind, that would be good.

I do have one thought here. Will the fireplace be used mostly for ambiance and not for heat? These units are not good heaters at all. There are more modern units that will also really heat the house well. If it is just for a nice ambiance, have the fireplace and chimney thoroughly checked out first. This is an old dogger so you want to be sure that it is in excellent condition before encasing it in stone.If it is starting to show its age, I'd replace it.

PS: Welcome to Hearth.com Rick!

 

[RickE]

By the description that sounds ok, thanks for the clarification. If want to post a picture to get a looksee for greater peace of mind, that would be good.

I do have one thought here. Will the fireplace be used mostly for ambiance and not for heat? These units are not good heaters at all. There are more modern units that will also really heat the house well. If it is just for a nice ambiance, have the fireplace and chimney thoroughly checked out first. This is an old dogger so you want to be sure that it is in excellent condition before encasing it in stone.If it is starting to show its age, I'd replace it.

PS: Welcome to Hearth.com Rick!

Thanks! We use the fp maybe 10-15 times a year, at night for a couple hours for ambience. We had a chimney guy in and he cleaned it and said it looked ok. From what I can see, it looks ok, we had the firebox walls replaced about 4 years ago and they look ok.. I agree too that as far as heat goes this thing stinks! Attached is a pic, ignore the blue tape, that is my outline of new hearth and stone spacing on the walls...

Thanks again and this is a great site!

 

[RickE]

I have one last question (well, maybe not last), but in my framing, can I put a 2x4 nailer across where the triangular spacers are on top (ie cover the triangles with 2x4) ? I know the spacer is there for a reason, but I'm assuming its for internal framing, and that since sheetrock is surrounding the existing exterior of the fp, this that I can do the same with 2x4/plywood? Ultimately once complete, the scratchcoat would be hardly touching the metal faceplate around the FP. So no combustibles would be touching the metal, and I would follow the contour of the exisitng sheetrock. I always thought sheetrock was considered combustible as well so I think i'm safe, but wanted to validate again! Tx

 

[begreen]

If this were my house, at this juncture before encasing it in stone, I would consider replacing the unit. It will be more costly, but the benefits of much lower wood consumption, cleaner burning and real heat would be worth it to me. Some replacement models are ductable which might allow you to heat the whole house with the fireplace.