Tile Countertop

[Verdeboy]

I will soon need to install a ceramic or porcelain or stone (customer isn't sure yet) tile kitchen countertop. They want to use 12" x 12" tiles.

Questions:

What kind of board do you use? I was thinking of 1/2" plywood.

Is my choice of thinset the same, regardless of the type of tile?

Is it best to cut all the tiles ahead of time, spread the thinset, and set all the tiles at once?

How much time do you have to set the tiles before the thinset hardens?

I imagine that I need to make the cutout for the sink right off the bat.

Does the sink "flange" get mounted over the tiles, or should the tiles come up to the sink, but not under it?

If I have to trim some of the tiles that overhang into the sink cutout, what's the best method for doing this?

[markts30]

I would use a thicker plywood for the underlayment and cover it with cement board...
The tile should go under the rim of the sink...
I have used tile nippers and an angle grinder with diamond blade to trim tile in this type of situation in the past with fair results...

DISCLAIMER: I am a plumber, not a tile setter...(and I tend to over-build things)

[jadnashua]

You want more ply than 1/2"...some people use two layers of 3/4"! Keep in mind that it would not be unheard of to have kids or even adults climb up onto the countertop on occasion to do things like finish painting the wall, get that last bit out of the highest shelf, etc.

Depends on the sink you choose best how to do it. There are some sinks that are designed to be tiled in and typically are square so you don't have to deal with curves when laying the tile up next to it (these are typically cast iron sinks). But, yes, if it is a dropin, then tile to the edge of the rough opening so that the sink will both fit and cover the raw edges. You might want to waterproof those edges in case any water leaks under the rim.

The cement board is not really structural in this instance, so the thinner stuff works well. You can also use a membrane like Ditra (available at HD in small rolls) which is waterproof if you seal the seams with the Kerdiband. Another thing that works is Redgard, also available at HD and tile stores by Custom Building Products. You paint this stuff on, then can tile over it once it is cured.

One of the harder things to sometimes come to grips with is finishing the edges. Wood can work, tile works, and if you use stone, you can have the edges polished and or bullnosed.

You'll get some other ideas if you visit www.johnbridge.com (http://www.johnbridge.com).

[geniescience]

...What kind of board ...Porcelains are fantastic for countertops. And epoxy grout. Get the white thinset if the grout lines are going to be light color.

Like Jim said, many membranes are good and they all work. Thinsetting directly onto plywood has been done successfully too, but not by all.

Why 12"x12" tiles? You could use bigger ones. Some porcelains are 24"; does that fit the depth? What size is the counter? Whether to cut some in advance depends on a lot of factors.

Have you set tile before? Your question about thinset hardening...

David

[Verdeboy]

Porcelains are fantastic for countertops. And epoxy grout. Get the white thinset if the grout lines are going to be light color.

Like Jim said, many membranes are good and they all work. Thinsetting directly onto plywood has been done successfully too, but not by all.

Why 12"x12" tiles? You could use bigger ones. Some porcelains are 24"; does that fit the depth? What size is the counter? Whether to cut some in advance depends on a lot of factors.

Have you set tile before? Your question about thinset hardening...

David

I've only done shower tile repairs using the tile adhesive that comes in the 1 gallon buckets, so I don't know about the properties of thinset. As far as the tile size, the owner is going to pick up whatever tile remnants she can find.

[geniescience]

ok, got it. For a cheapie client, in a cheapie market, i'd just make sure the base is solid and let everything else get decided based on what the weekly special is at the local low cost store. Tell them that any two teenagers dancing on the counter will cause cracks in the grout within a week or two. The tiles have to be strong. Tell them to seal the grout, wipe up visible water, and not leave wet things on the countertop.

david

[hj]

It depends on the sink. There are self rimming sinks that set on top of the tile, square corner ones that set into the tile flush with the tile, or standard flat rim sinks that go under the tile, with a bullnose trim to cover the tile's raw edges. These are the most common cast iron sinks. Stainless and enameled steel would either be undermount or use a stainless steel rim with long clips.

[Verdeboy]

She's gonna just use the sink that is already there. I'll take a photo of it so it'll be easy to decide the right course of action.

[Verdeboy]

Here's a photo of the sink we are going to continue to use: Should the tiles go under the rim or up to the rim?

[frenchie]

That would be the "stainless steel rim with long clips" type, which are meant for laminate countertops... I don't know if you can get clips long enough to hook onto a tile countertop, which is considerably thicker.

If you're doing something as high-end as tile counters... I'd spring for a new (undermount) sink.

If you don't want the tile to pop up within a week, learn about proper substrates & adhesives. If I recall, for a tile counters you want 2 layers of 3/4, wonderboard (layed into thinset & screwed), all joints taped with thinset, and the tile adhered with latex-modified thinset.

Browse the book section at the box store. 20$ on a good tile book, is a worthwhile investment. Really, it is.

My personal fave:

http://www.amazon.com/Setting-Tile-Homebuilding-Michael-Byrne/dp/1561580805

Hey, only 13.57!

[jadnashua]

By far the easiest is to tile under it, then mount the sink on top just like on the laminate counter. This also means that you can replace the sink later, if you decide to without tearing up the counter.

An alternative is to make it look like an undermount, and mount the rim on the underlayment, then tile over the edge. You need to be careful about the exact heights, may need a router to get it just right and then you need to be very careful about shaping and polishing the edges of the tile that would be exposed. If you do this, and it comes time to replace or update the sink, you'll tear out the counter. Shaping and polishing granite is an acquired art and requires skill and some special tools. An alternative is to have a shop do them for you, at about a buck an inch is typical.

If you go to www.johnbridge.com , you can find some pictures of this technique.

[statjunk]

I wouldn't got with any less thatn 3/4" Ply with 1/2" backer on top of that. You will get too much flex and the grout will start to crack.

Tom

[geniescience]

here is where I'd use Kerdi, since it is so thin. Or a paintable membrane. Or 1/4" Hardi. (And not Ditra, since it's not a continuous layer, it leaves little air gaps, and a countertop space is so small I'd want a continuous layer instead of a number of micropillars separated by a plastic waffle).

Only the plywood adds strength of the kind needed for a counter top.

CBU, cement board, is not strong in the snap-flex-bend sense of strong, it is strong in other ways not relevant to what is needed here. Only ply.

If you have an uneven number of layers in the plywood, orient them so the stronger axis is put to use across the larger space unsupported. Actually, an uneven number of layers is good here (even if less than total 3/4" thick), and if you can glue the two or three plys together you get a space age strong counter.

david

[Verdeboy]

Do they make a CBU jigsaw blade for making a sink cut-out or do I need to break out the rotozip? Or, if using 1/4", can I just score a sink cutout and pop it out with a cold chisel?

Also, do I glue the hardi to the plywood or countersink some screws?

[geniescience]

more reason to use Kerdi or paintable trowelable membrane that comes in a paint can.

Or no membrane at all. Scoring the top of the ply and soaking latex additive into the scratches first, before thinsetting, ensures adhesion. Read up on that at the thinset manufacturers' web sites.

Don't think that CBU is needed absolutely. People spec it because they always have. Get it? It is "spec'd" because it is so often spec'd.

CBU's sole purpose is to decouple tile from wood, period. And why decouple? Because over a large large surface the two materials expand and contract at different rates over the course of seasonal changes in humidity and temperature. Here, you have a small small area, and your climate is stable, stable, not with four totally distinct seaons like what I have, where humidity in spring and fall is low, and then high again in winter and summer. Long story short, you don't need CBU, and you don't need all that much decoupling, and you DO have the option of tiling directly onto plywood, as all thinset manufacturers will tell you if you read their web sites. Don't overdo this countertop. just 1. ) Make the ply strong, and 2. ) Decouple a bit or ensure a strong bond so that the tiles don't come off. Please realize that tiles coming off is the big hot topic among tilesetters. It's called delaminating. It makes big tiles sound hollow when you tap on them. It happens a lot, in all kinds of installations. The more quality time you spend with the ply, the more you will reduce risk of tiles delaminating later. Using big tiles is better than small tiles since they may still stick partially while delaminating partially. Grout is necessary to hold tiles in place too, so nobody should put pressure on the tiles while ungrouted, and not until the grout is really old either.

The total area to be tiled is 12 to 20 square feet.


david

[Verdeboy]

Regarding the weather in Silver City:

We're at 6000 feet, so we do have quite a bit of snow in the winter, and it gets down into the teens at night. Also, we have some very hot and dry months (90's and 100's) and some cooler, very humid months, like right now during monsoon season.

How does that factor into the equation?

[geniescience]

now we are getting into real fine-grained detail, and i may regret mentioning climate, when the surface area is so small to start with. On the jbridge site, one DIY located in Maine described how he tiled directly onto plywood and twnetyfive years later it was still impeccable. This was a large floor area that got walked on, had furniture moved around on, etc. All of this is to say, that a countertop that doesn't have pianos moving around on it, and isn't getting light or heavy foot traffic, can hold up longer than a floor, and on top of all that, it is a small area, thus has little contraction and expansion differential between the two materials. No matter whether you use CBU --- or any other decoupling which is not a cement nailed down --- you must have a good strong counter to start with.

I have seen tile last decades on plywood counters, where the area of the counter is larger than yours and the climate produces more severe swings in ambient conditions.

I have seen tile last a long time on plywood floors, and the eventual hairline cracks are all due to the plywood flexing. You can tell by the type of failure what the cause was, in most cases.

Thinner decoupling is available to you. There are many types.

Not decoupling is also an option. As described above.


david

[frenchie]

But using a single layer of ply, isn't.

Flex = popped tile.

Just my 2c...

Also - I have to disagree that bigger tiles are better, my understanding is that it's the other way 'round. The smaller the tile, the more tolerant of expansion/contraction & flex. Small tile allows cracking at the grout lines, whereas larger tile is more likely to crack the tile itself.

[jadnashua]

Hardi brand of cbu cuts different than those made of mostly cement. WIth any of them, though, the dust is dangerous - silicosis is as bad as asbestosis. You can use a carbide jig saw blade, but be very careful of the dust...do it outside if possible.

Always put thinset under cbu then anchor it with either the special screws or hot dipped galvanized nails (not the electro plated ones). Granite tile is not cheap, decoupling is, use it. If you are going to tile directly to plywood, you really want two layers and a highly modified (read much more expensive) thinset. If the house has the more traditional swamp cooler, the humidity levels can vary radically between summer and winter. Being at that elevation, you could be sitting in fog for a few days, then things change back to normal. Admittedly, you aren't going to be walking on the counter much, but you'd be surprised what does happen there sometimes.

There's doing it right, and then there's doing it so it might work. I think doing it right should be stressed, and if the user chooses to do it some other way, that's his problem. Let's not get into the situation where we are giving 'maybe okay' answers. There are industry standards. All it takes is one 250# hubby crawling up on the counter to change a light bulb or do something else, and the countertop cracks. It might never happen, but built to acceptable standards, and it would survive. For the small difference, why risk it?

[geniescience]

eloquent!

Redgard is a decoupling membrane. So are some Mapei products. There are many more. And Kerdi too.

Cement board CBU doesn't add strength.

David

[Verdeboy]

I doubt she is going to go with granite tile. I'm guessing she will pick up something relatively inexpensive.

Also, how do you recommend tiling the overhang of the countertop? There are no 12 inch "edge" or "bullnose" tiles that I am aware of. And how much should the tile overhang beyond the bottom of the plywood?

[geniescience]

the edge is where you really need the decoupling membrane. Kerdi or the paintable kind is easy there, and if you use CBU it has to be cut into strips, screwed and thinsetted down - not elegant but it works. If you are worried about strength, you thinset galv lath on top around the whole thing, like they do for shower curbs.

the tiles' edges can be hidden with a schluter edge profile trim piece. Or you can cut them back miter 45 degrees with a wet saw and get a tile to tile corner. Or you can butt them together and call it good looking.

david

[jadnashua]

You can use a wood edge, but it needs periodic maintenance which you may be trying to avoid. Cutting the tile on a 45 can work, but often leaves some very sharp edges and, if a glazed tile, often exposes the body of the tile's color. I used a strip of Corian, but in looking back, it would have cost about the same as having the granite tile bullnosed, and may have been better. The Corian is probably more resilient. I've searched for the on-line manufacturer who had a huge line of wood, solid surface material, laminated,etc. for counter edging in numerous shapes, but didn't find them, or I'd give you a reference, but they're out there. I had to special order it through a local lumberyard, but found it on-line.

[geniescience]

no, when you cut the back side you aren't exposing the body of the tile, it is the opposite; you are wrapping two face sides around the corner, and the space is grout filled so that rounds out the edge very well.

if you are considering going with another material to cover the edge, consider the Schluter Treppe line of edging.

if there is budget, i'd use epoxy grout. It's waterproof, looks good, and handles stress, flex, vibration and movement very well so that actually protects the tiles mechanically better than regular portland cement grout which is incompressible and transfers mechanical stress to the tiles.

david

[jadnashua]

Your experience is different than mine. Making that sharp point often will cause it to chip a little. On a "normal" edge of a tile, there is usually a little round-over, and the glaze extends a little beyond that upper edge. When you back cut a tile on the 45, all you have is the thickness of the glaze, miniscule, and it can be sharp as a knife and fragile. Getting it grouted and looking good, on a highly visible, often used surface doesn't sound like a good idea to me....maybe on a trim edge on a wall.

[geniescience]

yes, i wouldn't advise cutting it exactly through the corner, as that could leave a sharp edge; instead cut through most of the tile -- up to and not right at the corner, leaving a millimeter or more of the side of the tile.

So, the corner of the tile stays intact. When both tiles are laid the gap is large enough to hold grout, and then the corner is rounded by two full corners and a grout gap. Where the glazing ends is often wrapped around the side a millimeter or two, so the corner is good looking.

david

[geniescience]

i guess the best analogy is the "pencil edge" you can see on well finished tempered glass panels that have no hardware around them. The corner is softened by adding one more edge that is about a millimeter thick between the two sides and that cuts the angle by half. A 90 degree cut edge glass panel would have two corners of 90 degrees each, but instead it has four corners of 135 degrees each, in two pairs about a millimeter apart, so from a distance it still looks like only two corners.

in the last 18 months I have cut more than 200 feet worth of tiles this way, tiles ranging from 6 inches to 18 inches in length. Sometimes I did cut too close to the corner and got a sharp edge; sometime I left so much of the tile that I went back to the saw and used the spinning blade sideways to sand down a bit more off.

david

[dx]

Verde,

First get yourself a TCNA handbook. You will note that there is no recognized method of installing tile directly on plywood.

In plain English, this is not a good thing to do. Depending on many factors and your experience/proficiency, you may or may not get away with it. But you won't get the tile, grout or thinset manufacturer to warranty it.

A better thing to do is make a stiff plywood base like 1-1/8" and then cement board or Hardi on top of it.

dx

[geniescience]

Rondec-Step is the schluter product made for countertop edges.

It is true the TCNA handbook doesn't mention plywood; there has been no effort made to do the testing. This is normal; no criticism implied.

David