Bathroom Cararra Marble Flooring Grout Thickness

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  #1  
Old 01-28-15, 11:21 AM
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Bathroom Cararra Marble Flooring Grout Thickness

Contractor wants to use 1/8" unsanded grout to ensure the grout can reach down the edges of the tile. Wife (important) and myself really want 1/16". Any concerns with 1/16"? If yes, is there a grout thickness in the middle to consider?
 
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Old 01-28-15, 03:12 PM
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Are you saying the end results will be ⅛" wide or he wants to gap the tiles ⅛"? As you probably know, the edges of the tiles are chamfered so ⅛" gap means the grout width at the surface will be a little wider. The grout will be just below the surface though.

I wouldn't gap the tiles any wider than 1/16", better yet 1/32" or credit-card thickness is the norm around here as long as the tiles are high quality. Both these widths are common for polished marble tiles. I don't remember what the MIA, Marble Institute of America recommends, but will check when I have time.

A much more important thing is; What do you have as the substrate and how will the tiles be installed? Slab, suspended wooden subfloor system. Method of installation. Please reply with details especially if the floor is wood.

Jaz
 
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Old 01-28-15, 03:14 PM
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You will need at least an 1/8" to maintain your square and grout lines. Tiles seem to be rarely square and the slightest variation will completely throw off the grout line while trying to lay the floor. Give your contractor at least 1/8" to compensate. Any less and he may have to individually shave tiles that mess with the line-up of the grout lines.

Personally, I usually do 1/4" on floors and 1/8" on walls. Even if the tiles are rectified, you can not be sure that you will be able to keep the tight fit you desire. Measure a few to see if they are indeed square. Then stack them on a table together and flip the various sides around, it you see differences, go for the larger line..

Jaz types faster, but the key in his response is "as long as the tiles are high quality".
 
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Old 01-28-15, 03:27 PM
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" wide grout with marble tiles......really? Tumbled travertine maybe , but not with what this thread is about. And therefore you must use sanded grout right? So much for the polished part..... My clientele would not accept that.

Marble/granite tiles are rectified and very square. The biggest variable is the skill of the tilesetter.

Jaz
 
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Old 01-28-15, 03:37 PM
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The grout spacing can be whatever you want. Yes, you can do 3/32" but the natural variation in tile & stone sizes can start to cause trouble. Some are very uniform but others can vary that much in the X and Y direction not to mention from one pallet to the next.

I've seen floors where the stones are almost touching, maybe 1/16" and there were areas where the grout either came out or never was there in the first place. At that point .0625" you really splitting hairs and bordering on no spacing and no grout. With that fine a spacing I tend to think of grout as hiding imperfections and not there as a design detail. If you want a grout line that looks like a grout line I'd tend toward the 1/8".
 
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Old 01-28-15, 03:39 PM
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I'll admit, I missed the marble part - Been a long day....

And I have been frustrated by sub par tile one too many times. I was just quick to warn others of the to be on the lookout.
 
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Old 01-28-15, 04:29 PM
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Thanks for replying czizzi, for I moment I thought you had lost it.........

Dane, Polished marble tiles should all be the same size when they're selected from the same manufacturer's batch, (as they should always be). You can run off a bit if you're not experienced and/or if the substrate isn't flat. It's almost always installer error. That's one reason labor cost for marble is 2-3 times that of ceramic tile.

Jaz
 
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Old 01-28-15, 06:26 PM
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Are you saying the end results will be ⅛" wide or he wants to gap the tiles ⅛"? As you probably know, the edges of the tiles are chamfered so ⅛" gap means the grout width at the surface will be a little wider. The grout will be just below the surface though.


He suggested using the 1/8th "spacers" rather than 1/16" but did acknowledge that "most people prefer 1/16". His only concern was that the grout would not reach down in between the tile.

I wouldn't gap the tiles any wider than 1/16", better yet 1/32" or credit-card thickness is the norm around here as long as the tiles are high quality. Both these widths are common for polished marble tiles. I don't remember what the MIA, Marble Institute of America recommends, but will check when I have time.


Is there any consequence for going less than 1/16" or is this only aesthetics? The marble came from $7SF Carrara Subway Tile, Basketweave, Hexagon, Herringbone, Bianco Carrara marble, Glass subway tiles, Metal mosaic and appears to be of high quality especially given the reviews.

A much more important thing is; What do you have as the substrate and how will the tiles be installed? Slab, suspended wooden subfloor system. Method of installation. Please reply with details especially if the floor is wood.


The subfloor is an existing 3/4" plywood, then a new 1/2" plywood was added, and then a new 3/8" harderboard was added. The tiles will be installed square against the back of the bathroom coming towards the bathroom door. At some point, the contractor will have to cut the tile near the door given the shape of the bathroom. I am not sure how else to explain it.

You will need at least an 1/8" to maintain your square and grout lines. Tiles seem to be rarely square and the slightest variation will completely throw off the grout line while trying to lay the floor. Give your contractor at least 1/8" to compensate. Any less and he may have to individually shave tiles that mess with the line-up of the grout lines
This contradicts the above recommendation of 1/16" and 1/32"!?
 
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Old 01-28-15, 06:37 PM
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I'd like to add that my contractor isn't the best tile pro. I was a bit concerned over the subway tile but the white grout cleaned up nearly everything to the naked eye. However, the floor is very expensive and important to me.
 
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Old 01-28-15, 07:21 PM
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Originally Posted by sagosto
He suggested using the 1/8th "spacers" rather than 1/16" but did acknowledge that "most people prefer 1/16". His only concern was that the grout would not reach down in between the tile.
He will force the unsanded grout into the gaps with the grout float and a little muscle. I hope he's not one of those guys that mixes grout like soup and uses a squeegee.

appears to be of high quality especially given the reviews.
I never pay attention to online reviews. There's 35 million people in CA and 319 mil in the USA, what 5 or 10 people write is meaningless. Some might be relatives or employees, who knows?

" subfloor plus " ply underlayment should be stiff enough. What grade of underlayment did you use and was it gapped? How fastened? Did you mean HardieBacker? Hardie does not come in ⅜" maybe you meant Hardie 500 which is about .42". They call it " for some reason though. Is the Hardie set into thinset mortar, gapped, fastened, (with?) and all seams tapped and thinset'ed.

You didn't mention the framing under the subfloor. Tell me the; size of the joints, their spacing, the longest unsupported span and if possible the species and grade. Condition and age might help. Framing specs for natural stone is diff than for ceramic.

I'd like to add that my contractor isn't the best tile pro.
Not a good sign. Marble is much harder to install than ceramic tiles and the specs for the substrate are different too. Even a pretty good tile guy might mess up marble.

Jaz
 
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