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Cover river rock fireplace with tile

I have a 35 year old real river rock covered fireplace and hearth. Some of the rocks and the cement holding the rocks together are starting to crack. It's also very bumpy between the rocks and not close to level at all. I would like to cover the river rocks with tile eventually but have read that I need to frame it somehow. Can someone please provide advice on the best method to cover a fireplace like this with tile? 
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Posted 2016-01-20T20:58:51+0000  by HPunome HPunome
Hi HPunome,

You will have to box in the top sides and bottom with wood, then install cement board as a backer for the tile. The cement board should be attached to the wood with screws and attached to the stone with concrete anchor screws. Once this is complete then you can use thinset to attach your tile to the cement board.

Posted 2016-01-21T19:17:51+0000  by Mike_HD_OC

Hello HPunome and welcome to the Community.

 Another way to approach this project would be to cover the surface with thinset, to create a flat surface.

Cover the hearth with a drop cloth and remove the mantel and anything else that's attached to the stones. Go over the entire area with a wire brush to dislodge any loose mortar, then scrub off the soot with a rag soaked in white vinegar.


Surface must accept water penetration. Test by sprinkling water on various areas of the substrate.  If water penetrates, then a good bond can be achieved; if water beads, surface contaminants are present, and loss of adhesion may occur. Contaminants should be mechanically removed before installation.  Smooth concrete surfaces, existing glazed tile, terrazzo, or polished stone should be scarified


Let the stones dry for a day or two, then mix up a batch of white, latex-modified thinset cement to the consistency of mayonnaise. Two good chooses are Megalite and Flexbond thinsets.  For complete product details click on the orange words and select specifications.

Spread the thinset over the stones with a flat, straight—not notched—trowel and force it into all the grout joints. If the joints are still visible after the first coat cures, skim on a second coat to fill in any depressions. If you do it right, you’ll end up with a surface that’s as flat as backerboard but without any seams. The next day, lay down a new bed of latex-modified thinset combed out with a notched trowel, and set your tiles into that. Don’t use mastic; it can’t take the heat.


Thank you for your inquiry



Posted 2016-01-21T19:33:17+0000  by Char_HD_CHI
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