Granite and ceramic tile fireplace surrounds

I am building a new home that will contain two (2) fireplaces. I want to use 12" x 12" granite tile for the surround on one of the fireplaces and 14" x 14" ceramic tile on the surround for the second fireplace. The fireplaces are zero clearance fireplaces. The tile will be installed over cement board nailed to studs 16" O. C. Here are my questions:

1. What thickness cement board should I use? 1/2" or 3/4"?

2. Do I need to use a special adhesive due to the close proximity of the tile assembly to a heated fireplace and the fact that the tile assembly will continually heat and cool? What do you recommend? Is an isolation membrane needed?

3. One of the fireplace surround installations will require attaching a portion of cement board to a sheet metal trim frame (the remaining portion will be nailed to surrounding studs). The fireplace manufacturer recommends simply screwing the cement board to the sheet metal frame. Since the screws will be covered with adhesive, what type of screws should I use to prevent rust and other chemical interactions?

4. Is there any issue with the weight of the granite tiles with respect to falling off of the surround before the adhesive has dried? If so, how do I deal with this?

Thanks in advanec for your help!

Bill Vallance

1. 1/2".

2. Modified thinset.

3. They make special screws for cementboard where you buy it.

4. They won't fall off, just use spacers to keep them from sliding down when setting.

Thanks for the help with this!

Bill Vallance

I also had a problem with this - couldnt get a straight answer on how to install the cement board to the metal trim surrounding the firebox. I was told by various contractors and fireplace dealers to use either thinset (which every manufacturer says do not use on metal) or high heat silicone sealant, which I used in conjunction with a few screws to "suck up" the board tight to the metal frame. My manufacturer said screwing into the frame would void the warranty, but I dont like relying on silicone to hold a cement board with stone adhered to it. Especially w/ possible movement from the heat. If you make sure you clear the inside firebox panels, I think you should be ok. Since no manufacturer gives a clear spec on how to do this, and I think they should, youre basically on your own with how to secure it. Anbody have any other thoughts on this problem?

Can you use ceramic tile over top of gyproc

If I'm correct it's a gypsum product and you can in dry areas only, not in showers or tub surrounds.

Looked it up, made overseas, where are you located?

We have two zero clearance fireplaces in our new home -one woodburning and the other gas fired. We want to completely cover the black metal surround. Can we install the tile directly onto the black metal surround?

Assuming a portion of the tile will be applied to what, a sheetrock substrate? Yes. Use a quality "modified" thinset. NO MASTIC and no cheap thinset.

I am interested in installing granite tile over my brick fireplace and I am going to use the suggestion in this thread. Which brand of modified thinset should I used? If someone can suggest a brand that I can find in homedepot or lowes that works for them. I saw some of the mortar has very short work time 45minutes.

Joan Home Depot sells VersaBond and it will work fine. VersaBond will have the 'pot-life' necessary for you to relax. The products with the 45 minute pot-life are usually 'rapid-set' products so stay away from those.

I have used granite and tested the durability of it. A must try for everyone!

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[www.planet-stone.com]