Ive been reading FH for about 10 years now but have never checked out this forum. Wow lots of info. Which made me think “hey… why not ask these guys a question”. I’m just finishing up on my lifes dream to design and build my own home and I’m using some brand of cultured “fake” stone for my fireplace and a wainscot around the whole house outside. I had the bright idea that I could sheath my fireplace framing with cement board and skip the scratch coat and metal lath. Anybody ever try this or see any reason why it wouldn’t work.
Thanks in advance
Moz
Replies
I assume you've got clearance from combustibles and whatever fire protection is required by your local code viz. the framing so won't go into that.
Hardibacker will let you fasten directly to framing that is 16" OC or closer. I've used the 1/2" Haribacker that way in a marble shower surround I did a couple years ago and as far as I know it is holding up without any problems.
Only quesiton I have for you is the weight of this cultured stone. Is it comparable to typical stone tile or is your stuff 2" thik or something? If it's really heavy, I don't know if the pull through and shear on any kind of CBU would be enough.
"A job well done is its own reward. Now would you prefer to make the final payment by cash, check or Master Card?"
Edited 3/24/2006 8:19 am ET by philarenewal
Not a direct answer to your question, but the building I am working on now will be sheathed with 1/2" durarock. The durarock will be sprayed with a product called Laticrete (sp?) that is supposed to crystallize a water barrier. Then a veneer brick will be put on with thinset.
I think the issue of weight of your stone, as suggested above, may be the biggest issue.
Mike
Trust in God, but row away from the rocks.
Weight is not an issue with cultured stone. As long as your framing is to their specs, the weight of the stone isn't a factor. Can you skip the lathe? Their instructions recommend lathe, last I looked, so I won't recommend otherwise. That said, for some limited interior areas, I skipped the lathe, added some acrylic to the mud, back-buttered the cultured stone, and have had no problem. Did the same on CMU wall, and can't tell the diff. One reason in favor of lathe with the cement board is that it'd help to keep any edge movement from telegraphing through the stone and cracking it. I'd worry about water penetration with an exterior application. They have thorough instructions...follow them for best results.
I just finished adding ledgestone (manufactured type) to the face of my fireplace (interior work). The fireplace was woodburning and done with brick. I installed a gas insert.
I used 1/2" durock on top of the brick, rough side out. I anchored it to the existing brick with 1/4" tapcons. If I was anchoring just to studs, I would have used two layers of 1/2" board for rigidity (maybe overkill, but better to be conservative in my opinion).
I back-buttered the stones and applied. I installed them bottom up, instead of top down. This is my third project with these stones. The reason for bottom up is that it looks pretty silly to have a line of cut stones where they meet the hearth. This is fun to do. I used a 4" angle grinder with a masonry wheel (diamond) to do any trimming (cut outdoors with ear, eye, and respirator protection - lots of dust!). Back cut any cuts so the cut is not seen. I used a dry stack technique, too. I laid the stones out first on the floor in the dimensions of the area that I was going to install them. That way, you can move quicker, and have a very good idea of color and size blend. If any mortar oozed from between the stones, I raked it out after the mortar set for an hour or so.
I did keep a spray bottle handy to mist the durock and the back of the stone before applying mortar. Probably unecessary, but I did it. I did not apply a scratch coat.
Turned out great. Just work diligently, and be careful not to smear mortar on the face of your rock. You can't wash these down with acetic acid. Keep it clean. You'll enjoy the results.
It should work fine but do NOT use hardi brand products, they are not rated for exterior use. Put a moisture barrier between the backeroard and the the framing.
The fireplace is outside?
Here, we'd call that a barbeque.
"A job well done is its own reward. Now would you prefer to make the final payment by cash, check or Master Card?"
I've done this many times (interior only) and never a call-back. As a matter of fact I'm doing it in my son's home right now. I put the rough side out, and I use galvinized screws in the cement board to hold it to the framing.
I have done that both inside and outside a few times and it seemed to work well. Just make sure you get the right material.