Cutting Porcelain Tile [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-21-2001, 03:34 PM

We're getting ready to install porcelain tile on our bathroom floor. I've heard that we need a wet saw to cut it. Is that true? Our subfloor is 3/4" particle board and we will put down 1/4" cement board over it (this worked great for ceramic tile in our other bathroom). Also, how do we adjust the toilet for the tile? Do we need to move the drain pipe up to a new height or is the wax ring with the rubber flange enough to account for the new floor height? Any advice appreciated!

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John Bridge
08-21-2001, 04:27 PM
Hey, you forgot to pick a handle (username). You can go back to the profile and enter one. We'd like to have something to call you. :)

We don't like particle board around here. It can really swell up when it gets wet, which is likely to happen in a bathroom. I know you said it worked great in the other bath, but how long ago was that completed?

Bud Cline
08-21-2001, 07:12 PM

Meet Holly, I kidnapped her from a place where she wasn't going to get any help and brought her here where the help is plentiful, questionable, but plentiful.

Holly, the particle board could turn into a real problem for you. Also, the 1/4" cement board on top of it really doesn't bring you up to par with any current standards as far as subfloor thickness.

I know you said this worked fine before, but these type installtions sometimes take a little longer to blow-up in your face, but when they do they are very expensive to correct.

Maybe you don't want to hear all this, I don't know, but we're glad you're here.

08-21-2001, 07:26 PM
Hi Holly,

I recently finished a large job of porcelain tile. This was my first time to use porcelain so I had the same questions you do regarding cutting.

I was advised not to use a "knife" scoring cutter since the porcelain would chip. Nonetheless I gave it a try.. The result was not pretty. The tile shattered like glass.

In short porcelain is very strong but also brittle. I used a wet saw with a porcelain blade. The guys will tell you that porcelain reaks havoc on blades since it is harder than ceramic. I did about 1500sq ft on one blade with no problems. Just keep the water pumping and cut real slow...slower than ceramic.

My advice is to rent a good wetsaw and invest in a new blade. For interior cuts , use a dry cut diamond blade on a grinder. I used a Dewalt DW4701 4" blade for my cuts and was pleased with the results. This blade has also endured porcelain quite well.

As for the particle board and CBU...I'll leave that to the pros


Bud Cline
08-21-2001, 10:51 PM
Hey guys go to DSFR ( and check out this Patti's answers to Holly's questions.

Patti has been watching too much HGTV also.

[Edited by Bud Cline on 08-22-2001 at 01:03 AM]

08-22-2001, 04:36 AM
I told you guys this tile settn' stuff was a breeze.

You guys just try to make it sound hard, so others won't try it and you can do it all yourself.

$15.00 cutters and nippers. Mastic and mosaic's around the toilet.

Nothin' to it.

Heck even I could do it.

If I wasn't so concerned about these baby soft hands and all.

Art (just playing through) Phenis

Craig Meston
08-22-2001, 05:34 AM
So, you want to lay porcelain. bring it on. you do not have to have a wetsaw, except for the really tricky cuts that like to shatter when you almost have them finished. you need a Rubi cutter (nothing less than a TS40) with the little tiny wheel. you will score and break that porcelain like butter and you will have a beaut clean snap. wetsaws will help you for the difficult cuts, but the Rubi will get you there. make sure you use an adhesive approved for porcelain, because a lot of companies making cheap porcelain put too much release powder on the back and the adhesive just sticks to the powder and then youre screwed later. hope you have fun, craig meston.

John Bridge
08-22-2001, 06:20 AM
Okay, the longer I hang around the more ignorant I become. So what's a Rubi cutter?

On Spreen's board, I notice Patti used 1x1s. She didn't have to make any real cuts. I don't think she's aware of the sizes available in porcelain tiles.

Rob Z
08-22-2001, 06:30 AM
Rubi is a brand name. they are sold at one of my local suppliers.

My Tomecanic will snap most porcelins. It's ahigh $ cutter, though, and probably not on the shopping list for Holly.


08-22-2001, 06:55 AM
Hi guys, it's Holly.

Thanks for all the advice. I can't really do anything about the particle board - that's what our subfloor is, although I was just guessing on the thickness of it. We have a small modular house...

We did our other bathroom about a year ago, along with the kitchen. We used a bad type of adhesive on half the kitchen and have had some problems but the bathroom looks and functions beautifully! I didn't want to use 1/2" cement board because of the height difference but would that help correct for our subfloor? We used the 1/2" under the granite tile we laid in the foyer...we've done a lot to a house we only plan on being in for a couple of more years! We even did hardwood floors...and don't get me started on the crown molding in the garage...LOL. My husband insisted on that...

Thanks for any advice guys! Gee, are there any other women on this board?

08-22-2001, 08:32 AM
Would ceramic tile be a better option? Just thought it might be lighter...

Bud Cline
08-22-2001, 08:51 AM
just my opinion


I don't know what it's like "down under" but in this country when sending a DIY'er to a tool rental house we must keep it very simple.

Rubi cutters are readily available here for sale but I doubt that most rental houses would spend the money. All I have ever see is the cheap cheap cheap cutters from China, tool rental people don't know from Rubi.

To knip a 1" porcelain is no big deal, but to ask or expect a DIY'er to be able to "score and pop" or even knip a large porcelain tile is asking too much I think. Though not really difficult, as you know this does require some experience so as not to waste a lot of product during the learning process.

I would say rent a wet saw under all circumstances and get on with a successful job. Knippers and scoring tools tend to frustrate.

I also invited Patti to come along on this ride, we'll see if she shows.

I would stick with the porcelain, I don't think swapping glazed ceramic for porcelain is an even exchange.

08-22-2001, 09:13 AM
Hi Holly,

Don't give up on the porcelain. It is a little more difficult to cut but the benefits outweigh the added effort.

A good wet saw will serve you well. You may want to lay field tiles first, then rent a saw for the cuts. This may save some money on rental fees.


08-22-2001, 09:17 AM
Thanks for the tips guys...I wish we would've found this site before we did the kitchen! I think we will lay all the field tiles first...then we should only have to rent a wet saw for a few hours...

08-22-2001, 11:19 AM
It's me again...I went and looked at different ceramic and porcelain tiles at lunch today and EVERYTHING I liked (except the natural stone of course) was porcelain. So, I bought the 12X12 porcelain tiles that I like in the first place. Now, I have more questions. I know we need to use different thin set for porcelain, but what kind? Do we need sanded or non-sanded grout? (I liked working with the non-sanded stuff we used on our granite).

One other thing, boy is this stuff heavy! It seems a lot heavier than ceramic tile. So I probably should use the 1/2" cement board instead of the 1/4"?

Bud Cline
08-22-2001, 11:48 AM

Your proposal to set all field tile to have a minimal rental of the saw is a means of reducing costs, just don't set field tile near your door jambs (if you intend to tuck tile) because some times you can't get the jamb tiles in place after the nearby feild tiles are set. It is often necessary to install tile "B" before "A" is installed.

Wider grout lines require sanded grout. Normally 12 X 12 tiles are set with a 3/16" to 1/4" grout space, this requires sanded grout.

As far as the thinset, read the directions on the bag, this will tell you whether or not the product is suitable for porcelain. And don't buy the cheapest thinset you can find, spend a few dollars more here.

08-22-2001, 02:30 PM
Hi Holly,

The porcelain is indeed heavier than the basic ceramic. However, I do not believe 1/2" board is required strictly because of the tile weight. 1/2" CBU is usually reserved for wall tile; 1/4" should be fine for the floors.

Whada ya think guys?

Also, check the mfg's recommendation on the thinset for the trowel size. I believe the Mapei products require a trowel that is 1/4 X 3/8 in size.( 1/4" wide, 3/8"deep). Custom and other brands may differ.


John Bridge
08-22-2001, 05:10 PM
Hi again, Holly,

I'll leave all the technical stuff to the other guys.

Yes, we have girls. One of out professionals is Jacqui. Jacqui is in the businees full-time with her husband Derek.

If you look down the list to "Ready to grout," you'll find Daisey "racerette" French, who is building a shower with our help.

Lynda has just completed her shower, and Texas Girl (Liz) has just recently joined us.

Besides that we are all married (or have full-time, er, uh . . . . somebody bail me out). I've done it again . . .

Rob Z
08-22-2001, 07:38 PM
Hi Holly

One school of thought is that 1/4" cement board should be used on floors because cement backer board is not considered to add any structural integrity to the house, and the thicker cement board only adds more weight (dead load).

This is the subject of much debate, which we will spare you the details.

I don't put much backer board on floors, but when I do, it usually is the 1/4 " variety.


01-28-2005, 07:16 PM
Many pro's have different techniques about how to do this,
So, Some may offer you different views.
Here's Mine.

First off, There is a thing called Durock, Or backer board, This is made of cementous type material, that comes in a 3' x 5' sheet. around $10.00 ea.

it comes in 1/4" and 1/2" or 3/8" and 5/8" Thick, depending on brand.
Anyway, what this does, Is creates just about ANY subfloor, into an ALMOST concrete floor, WITH PROPER INSTALLATION,
Proper installation is as follows.
MEASURE your room, Try to use as much of 1 piece as possible at one time.
less seams= more strength.
Once you have your board cut, to where it covers your floor, USE THINSET, which is called different things as well, I use sturdyflex, or full flex.
remember when buying, cheaper, is NOT BETTER.
Set your board using the thinset, then SCREW the board down, ALOT of "tile Mechanics" say this isn't needed, but, if you want it done right, and 110% stronger, DO it.
Screw the board down, spacing within 6" apart from another.

After your board is down, If you do not intend to lay the floor NOW, Flat Trowel the remaining thinset, Over any joints, This will bond each board to each other, as well to the floor, Creating One solid floor!

Then your ready to do the floor.,
IF anyone has questions, Please feel free to contact me via my CHEAP YAHOO EMAIL address,
Thankyou, and goodluck

01-28-2005, 08:14 PM
Howdy, tileguy. :)

That thread you just responded to is about 3 1/2 years old. We have enough trouble keeping up with the current ones these days, so I'm gonna lock this one to hold down the confusion.

We welcome all the help we can get from pro tilers, but please register and come on over to the Professional's Hangout and introduce yourownself. Lotta friendly folks there.