need advice [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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05-26-2009, 11:28 AM
I was contacted by client who wants me to tile fireplace. The existing has a crack. Should the crack be treated? How would you prepare the surface for tiling.
Thanks Michal

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05-26-2009, 12:46 PM
Yes, that will certianly need attention. Is that onyx tile that your installing? If it's green make sure an epoxy is used to set that.

05-26-2009, 12:49 PM
Can I just cut out broken bricks and put new ones. What kind of epoxy would you recommend?

05-26-2009, 01:03 PM
You can use other brands, I'm familiar with Tec's Epoxy Mortar and Grout

05-26-2009, 01:26 PM
Can I just cut out broken bricks and put new ones. What kind of epoxy would you recommend?

Even so,youd still need to put some sort of membrane on it.Your best bet would be Ditra/since there is no screwing.Cant believe nobody here has said that:idea:

05-26-2009, 01:31 PM
So, Ditra over crack and tile with epoxy? Why canít I use thin set?

05-26-2009, 01:39 PM
You can not use thinset with Green marble or any moisture sensitive stone. You should actually see it as an exclusion or limitation listed on your thinset product data sheets. Epoxy adhesive is required for these type of applications.

Does your marble have a resin backing on it?

05-26-2009, 01:54 PM
No, no backing. Never used epoxy, does HD or L's carry it? What brand is best,
thanks Michal

05-26-2009, 02:20 PM
As far as I know only the serpentines (really dark green stones sold as green marble) have issues with moisture in the setting medium. They tend to warp.

Serpentines are mainly comprised of Magnesium Silicate (with some iron and nickel in small amounts added for fun). Marbles and alabasters (onyx marbles, which is what Michal has there) are mainly calciferous in composition, hence their extreme sensitivity to changes in pH. There should be no issue with (white) regular mortar made specifically for marble installations.

05-26-2009, 02:21 PM
onyx is included in the list of moisture sensitive stones.

05-26-2009, 02:40 PM
IT looks like that junk marble from China that Home Depot sells. That stuff is really fragile. I used white modified thinset when I installed it and did'nt have any problems.

05-26-2009, 02:41 PM
i would get some water and a sponge and clean that stone it looks dirty. Hit it with fat mud and then membrane the whole thing something like hydroban.

05-26-2009, 03:06 PM
From the original pics it looks like onyx. Michal, if you can advise me further on exactly what type of stone you purchase I can further advise you on your setting material.

05-26-2009, 03:15 PM
it's onyx. I do not have any further informations about the stone. I'll ask the owner - he bought the tiles.
I do not mud, never done it.
My original plan was, repair the crack - cut out and replace the broken bricks, thin set the tiles. I'd use membrane if it helps. Should I wrap the whole FP with ditra or do I ran just the strip over crack (since the crack will be repaired)?
What do you think?

05-26-2009, 04:10 PM
Yes, use an epoxy, I'm not so sure you want to use ditra over that. I'm not 100% certain on your best solution there. Maybe one of our more experienced technicians can help answer that for you. All I can say is, Onyx is an expensive mistake, so let's make sure you get the proper fix.

05-26-2009, 04:20 PM
No way I would Ditra that, you'll have no coverage with that. Ditra wants a small notch, also their are other ways to do this job not Schluter related. Honestly I would wire that with 2 1/2 lb lathe and use stub nails or even with thinset and bond the mud to the thinset and then like i said before hydroban it. those bricks look too old and brittle. SGood job to learn mud.

05-26-2009, 04:33 PM
Where and why is there a crack? A fireplace that has had that much movement in a wall should be looked at and inspected to make sure it is safe. If it is only on the floor you are much safer. I use to do tuck pointing on fireplaces but don't any more. I found a great guy that will do a full inspection before a repair. he knows what he is doing. If I were to do work and not do a full inspection I have just assumed responsibility for any fire they had. More than I want on my conscious. Fire and electricity can kill.
If I am guessing to far ahead SORRY:stirpot: I just want all to go well for you :yeah:.

05-26-2009, 05:37 PM
Thank you all guys,
Iíll tell the owner to have it inspected by structural engineer, weíll go from there.

05-26-2009, 09:13 PM
I don't think you will have to bring in a structural engineer just yet. a good chimney sweep will probably be all you need They will do a video scanning clean inspect everything They know chimneys like you know tile. If they think it needs more attention they will tell you.

I like the stone and think it will look sharp when you are done!

Rob Z
05-26-2009, 09:23 PM
Hi Michal,

I think a good brick mason is more what you need, rather than an engineer. Could you post some more photos, showing the entire scope of the fireplace ? I'll run the photos past my buddy the mason that does all the work I need on my jobs.

05-26-2009, 09:36 PM

I see the "E" word and cringe....:laugh2:

It looks like you're a TEC rep, so I don't know about them, but I know that Custom makes a white thinset specifically for marble and granite. I just don't see what's wrong with using that.

05-26-2009, 09:46 PM
I'm not a TEC rep however, i have been to numerous tec classes and seminars because they are the setting materials our company primarily sells, working with them everyday makes me pretty familiar & comfortable with them. (hence a lot of products i suggest on these forums are tec) Custom's stone thinset is very similar to TEC's 3n1 (minus the lightweight technology). Serves as a thinset, non-sag, and medium bed product. However, on moisture sensitive stones you MUST use an epoxy mortar and grout, Here is the limitation's listed on custom's marble and granite mortar from their data sheet:

Do not bond directly to hardwood, Luan plywood, particle
board, parquet, cushion or sponge-back vinyl flooring,
metal, fiberglass, plastic and OSB panels.
When setting moisture sensitive natural stone or
agglomerates (check with manufacturer) use 100% Solids
Epoxy Mortar.
Do not use to install resin-backed stone.
When setting dimensional stone larger than 12" x 12"
(30 x 30 cm), contact Technical Services for recommendations
regarding subfloor deflection requirements.

Moisture sensitive marbles can curl or warp if you use a standard thinset. Most green and red marbles are moisture sensitive. Onyx being one of the most expensive moisture sensitive stones.

05-26-2009, 10:06 PM
Rob, here's the picture. Thanks a lot. Michal

Chad Deiter Construction
05-27-2009, 07:52 AM
I don't like that crack being in that top section. I like Ricks idea of lathe and refloating it. Or just tear it out frame it out of wood.

05-27-2009, 07:41 PM

Thank you thank you. Now that i see it, wrap the whole thing with wire and use stub nails 1" will work and a magnet to fasten the wire to the masonry joints not the bricks. Wrap all the outside corners everything with 2" overlap. I would thinset that crack through the wire with loose thinset and sprinkle water on the brick. One step float it and set your lathe, and plumb it all up. Then Hydroban the thing. I have floated fireplaces, it gives you a plumb surface to lay those tiles on, instead of that botchery you have there and you can set em tight like 1/16" or 3/64ths lay em tight!