Installing 18X18 Granite Tiles grout lines and adhesive question [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-01-2005, 09:01 AM
I am finally geting to my project which is installing my 18X18 granite tiles on my kitchen countertop. I have two sheets of 3/4 plywood with a 1/4 cement backerboard. Bob on this forum some time back when I inquired advised me to use Custom's Granite and Fortified Premium Mortar, is this still the preferred stuff to use ?

Also, the spacing. I prefer to use toothpicks as spacer so the grout lines are thin. My dad who is helping me with this project is advising me to use 1/4 inch grout lines. He says because we cut the edges on the tiles the thin grout lines won't look good because our tile edges aren't " factory perfect". Could someone please advise us on this issue ?

Thank you.

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08-01-2005, 09:05 AM
Also where can I buy "Customs Marble and Granite Fortified Premium Mortar" ?

08-01-2005, 09:15 AM
What did you cut the granite with, an ax? :D Use your angle grinder and slightly relieve (bevel) the edges of the tiles to match the factor edges. With the bevel and the toothpicks, the visible grout line will be about 1/8" wide.

HD should stock the mortar you need.

08-01-2005, 10:07 AM
Bob we cut the tiles with an MK 101. If we use the toothpicks as spacers without using the angle grinder and bevelling the edges, how will it look. Is my dad correct ? Will it look better with a little more space ? I wanted as little space as possible, but would like to know your professional opinion.

BTW it is more like I am helping my dad, because he has a lot more experience than I do.


08-01-2005, 10:43 AM
Bob, if you could answer my question id appreciate it !


08-01-2005, 11:05 AM
You do not need 1/4 inch joints. Do as small as possible with Granite. BIG JOINTS ARE UGLY WITH STONE. Use the toothpics.

08-01-2005, 01:41 PM
If you don't match the bevel (assuming there is one), then you 'll need to open the grout lines a bit to compensate, otherwise you'll have some grout lines wider than others.

You can use the 1/4" wide lines if you want. Most folks would rather go with narrower lines, so they might think wider lines look bad.

Make a mock-up of your countertop: Take a tile, cut it into 4 pieces and glue it to a piece of plywood. Make 2 of the grout lines with toothpicks, and leave 1/4" gaps for the other 2 lines. Grout. Tell us which one you like better.

08-01-2005, 02:38 PM
Hey bob I know I'll like the thinner grout lines. Thats a definite. My question is about my fathers concern of thin grout lines not looking to well due to the fact that the tiles dont have a "factory edge" but rather the edge is the result of us cutting the tiles with the saw.there is no bevel we are just talking about inside pieces

08-01-2005, 04:55 PM
You can create the bevel with a tile stone, or you can take them to a stone fabricator to bevel for you.

08-04-2005, 07:33 AM
OK here is where we are, today I am laying the tiles down and are not beveling the edges. We have three options.

1) Use 1/8 " spacers. This way we can make straight lines meaning, the seems between the tiles are very straight horizontally and vertically. However the big gap lines just look bad. I am building a kitchen island with an overhang on both sides so, I have to have a smooth edge on both sides while the inside corners should like straight, but since the tiles are slightly off this is not working out to good.

2) Butt the tiles, if I do this I think it looks great. My dads concern is that when we line up the tiles so they are smooth on the outside. the inside corners are off as is the linegoing across which I agree but the lines are smaller so you dont notice it as much. However, if we butt we cannot get grout in between which heard can lead to problems over time.

3) Use the toothpicks, this seems to be a compromise between the two. Here we can correct a little but we do have a grout line which in the middle where the four corners meet will still be somewhat off, but i think I would rather have a thin grout line a little off then the larger grout lines which in my opinion do not look good. We are using dark granite with a drak grout which i dont think will be that noticeable anyway.
.Can someone give an opinion ? Thanks.

08-04-2005, 07:35 AM
Also, my dad had already bought the mortar which is "hydroment" it was expensive and he said it is the best stuff to use. Is this ok ?

08-04-2005, 07:38 AM
Hydroment makes excellent products but knowing which product would help. Stone should be set with a Medium Bed White thinset.

08-04-2005, 07:45 AM
Todd can you reply about what I wrote above in regards to the grout lines ?

08-04-2005, 07:48 AM
knowing what kind of hydroment would help, unfortunatly i didnt write it down

08-04-2005, 07:53 AM
Got it this is the stuff he bought :

Hydroment PM™
(717 white/ 917 gray)

Polymer-modified thin-set mortar is suitable for setting porcelain, ceramic and stone tile in both interior and exterior applications. Hydroment PM is recommended for installing tile over plywood, backer board and approved waterproofing/crack isolation membranes, as well as existing ceramic and vinyl flooring.

Seems like the right stuff huh ? Is it good ?

08-04-2005, 08:33 AM
Todd can you reply about what I wrote above in regards to the grout lines ?

It looks like Todd just left so let me try to address this lingering spacing question of yours. Your Dad is saying increase the width of the grout lines because you no longer have a factory bevel edge, right? bbcamp above has recommended either trying to recreate this micro bevel OR increase the width of the grout lines somewhat where you have cuts, right? Bass, they are essentially saying the same thing and I agree with both. Maybe this drawing below will help communicate the point.

Both sets of tiles are equally spaced, call it 1/16". HOWEVER because the tiles in Fig. 2 have the "factory bevel" when grouted these spaces will appear wider than the spacing in Fig. 1. Therefore unless you recreate the bevel as bbcamp has suggested you should increase the spacing somewhat where this bevel has been removed so that all the grout lines appear equal in width.

Let me take a checkpoint with you now, does this explanation work for you? Or are we misinterpreting your question?


08-04-2005, 10:13 PM
Put the tile down tonight. Did not bevel the edges but got it to work out nice. Outside edges are perfect, inside corners are not perfect but pretty darn good I think. I like the inside corners. I used tooth pics as spacers so the grout lines ar tiny. In the pics the grout lines look large but are very small just the width of a tooth pic.

Moderators please modify the title of this thread to reflect there are pics attached. I think there are a lot of DIY who could benefit from reading this thread and seeing these pics.

I welcome critques of all kinds and bring the questions !!!!!!! Can anyone figure out what I am putting in the hole under the counter ? lol this should be fun!

08-04-2005, 10:18 PM
Please note that I am also going to retile the kitchen countertop and backsplash behind the kitchen island as seen in the pics also with the same granite. I have it cut it and already to go. Any advice on installing it on the painted sheetrock?

08-05-2005, 05:46 AM
Clean the paint of any grease with some TSP or other de-greaser, then lightly sand. Wipe the sanding dust off and then set the granite with the same thinset you are using on the countertop.

08-05-2005, 06:54 AM
John won't the weight of the tile rip of the cheetrock ? I was thinking of using the mortar and maybe drilling plywood into the studs to ensure there is not problem. what do you think ?

08-05-2005, 07:12 AM
Installing tile on sheetrock is done all the time. However, if you are still concerned, remove the sheetrock and install 1/2" thick backerboard.