That title right there is absolutely ripe for me to go off on a sophomoric, mildly humorous rant about the viability of inferior illegal plant use. But I’m not gonna do that. (Okay, maybe later…)

A soft joint, or control joint,  is simply one grout line, all the way down the length of your installation, that is filled with colored silicone or caulk rather than grout. The purpose of a soft joint is to allow movement in your installation without cracking tiles or grout. When placed properly it will absorb any ‘normal’ seasonal and structural movements inherent in structures.

There are guidelines that need to be followed for a soft joint to be effective. The TCNA guidelines call for a control joint every 20′ – 25′ in each direction for interior installations and every 8′ – 12′ in each direction for exterior installations. Interior installations which are exposed to direct sunlight also need control joints every 8′ – 12′.

This simply means that if you install tile in your living room and it is larger than 25′ or 30′ you need a control joint – period. It is non-negotiable. If you do not have it chances are likely that your tile installation will fail. The number one reason for tile installation failure (on a floor) is lack of proper control joints. You need them! *It’s either lack of proper control joints or improper coverage, there are conflicting views. Both will lead to a failure and both are installer error – both need to be correct!

You need them on wood, you need them on concrete, you need them inside, you need them outside. And no, that is not the beginning of a Theodore Geisel book. I’m simply trying to illustrate the importance of a soft joint in a large tile installation. Because it is. Very important.

Along with these control joints you also need to ensure proper perimeter spacing. This simply means that your tile around the perimeter of your room is not butted against the wall or framing. You need room for stuff to expand.

You don’t realize it but there are a lot of things in a structure which move – constantly. With temperature changes, normal construction shifts (settling), even sunlight causes enough significant heat to expand and contract structural elements several times a day. You absolutely need to allow for this movement.

If you do not allow for this movement your tile installation will not last long-term. Your grout will crack. Your tile will crack. Your dog will burst into flames. Your tile may ‘tent’ which means that there is so much pressure pushing two adjacent tiles together that the bond from the mortar will eventually fail and the two tiles will pop – literally – off the floor and tent. They will sit there right in the middle of your room looking like a little teepee.  I tapped a tile once in an installation which did not have control nor perimeter joints and they literally popped – loudly – and tented.

Control joints also need to be installed above expansion joints in concrete – whether you use a membrane or not. A membrane will allow you to ‘shift’ the control joint in the tile over up to six inches (depending on which membrane you use) but it still needs to be there. If your concrete has a control joint it needs to follow all the way up and through your tile installation.

Most grout manufacturers make a matching caulk or silicone which can be used for these joints. When cured they match the color of the grout exactly or nearly so. You can tell it’s there – if you look for it. Don’t look for it. I understand that a control joint may change the look of your installation – you may not like it. I know. I get it. I don’t like them either. But you need them.

The photo at the top of this post shows a control joint through the middle of a tile installation. This is right after I finished installing it so the caulk has not yet cured – that’s why you can see it. Once cured it matched the grout color exactly. In my next post I will show you exactly how to prepare this grout line as a soft joint and install the caulk or silicone.

I constantly reiterate the need for a tile installation to be flat. Not necessarily level, but always flat. This is the mark of a true professional and the thing that turns an ‘okay’ installation into a spectacular installation. (Did I just type ‘spectacular? Jesus…) Anyway, the method I use on floor tile to get it flat is fairly simple and ensures that each tile is the exact same height as the tiles surrounding it.

Before I show you that you need to understand, as always, that the substrate preparation is the most important aspect of this. If your tile substrate looks like a skate park you’re never going to get a flat tile installation over the top of it. Your substrate needs to be as flat as you can possibly get it. Take time with your preparation – it makes the rest of the installation run smoothly and gives you a solid foundation.

Start by getting a few tiles set and make sure they are all flat with your straight-edge, just place the straight-edge on top of the set tiles and ensure that there are no open spaces beneath it and that every tile is the same height. You can push down on tiles that may be a bit high or take a tile up and place a little more thinset beneath it to raise it some. Once you have that correct the rest is cake, baby! (You ever seen a cake baby? They’re messy…)

All these photos are of a travertine tile bathroom floor. I used travertine photos because it happens to be one of the least dense stones and usually have quite a few pits and open spaces in the stone itself. If the tile is ‘filled’ travertine, as this is, it is normally only filled from the front so that, once installed, it has no open areas or pits on the face of the tile. You can, however, see these open areas in the back of the tile. I’m gonna show you how to fix this, too. You get a two for one with this post.

Photo 1

Once you have the initial couple of tiles set, as in photo 1, just comb your thinset onto your substrate in a uniform direction. (Make all the little lines from the trowel go the same way) This eliminates the possibility of trapping air beneath your tile and leaving spots that are not fully adhered (hollow spots). If you make the pretty little swirlies they may look cool, but they can also trap air beneath your tile. On a side note: my spell-check just told me that ‘swirlies’ isn’t a word – so I’m makin’ it one.

In photo 2 you can see the back of the travertine tile. See how it has all those pits and crevices and empty spots? You’ll want to fill those up with thinset to give the tile a good, solid fill and, essentially, make it more dense and durable. Do this by using the flat side of your trowel (Photo 3) and scraping thinset along the back of the tile in every direction. This ensures it is completely full and there are no open areas left. (Photo 4)

Photo 2

Photo 3

Photo 4

-This is what is called ‘backbuttering’ your tile. You’ll more than likely run into that term a lot when researching tile – that’s all it is. For an installation where you have an inconsistent tile or a questionable substrate you can always do this, then flip your trowel around and comb thinset on the tile as well (make pretty little lines – not swirlies!)

Now that you have a good solid piece of shiny rock to put down on your floor, flip it over and put it there. Make sure you flip it over – shiny side up. When you place it in the thinset on the floor place it directly against the two tiles adjacent to it (Photo 5) so that two sides of the tile are actually touching the two tiles next to it. As you do this you can push the tile down to just the right height to be flush with the tiles next to it.

Photo 5

This will ensure that the tile you just put down is the same height as the surrounding tiles. You can take your straight-edge again and use it to push the tile down and get it to the same height. If your tile goes down too far – PULL IT UP! and put a little bit more thinset beneath it.

I yelled ‘PULL IT UP’ because for some reason people think that once the tile is down – that’s it. It can’t be moved. That’s not it. Until the thinset cures – tomorrow! – that tile can be moved, pulled up, adjusted, smashed, replaced, etc. Do not be afraid to pull it back up and put more thinset beneath it if it sets too low.

Photo 6

After you get the tile at the proper height, and this needs to be along both edges that are touching, then you can go ahead and pull it away from the two tiles to create your grout line and make sure you are, indeed, at the proper height. (Photo 6)

Then just insert your spacers and make sure it is in the correct place. (Photo 7) Pulling it back also ensures that there is full coverage between the thinset and the back of your tile. Remember those little ridges that the trowel created? The ones that were not fully squished down as you were adjusting your tile will be pulled slightly as you create your grout line and this will create full coverage and support beneath your tile.

Photo 7

Photo 8

-You can take your straight-edge and lay it across the tile to ensure that they are all perfectly flat. (Photo 8 ) If one sets a little bit high you can simply wiggle the straight-edge back and forth until it is flush. If it sets a little too low – PULL IT UP! (damnit) and do it again.

It may seem like a tedious process – it is. But when done correctly you end up with a totally flat, professional looking tile installation which will last for years.

See:

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We, meaning us evil, scheming people in the tile industry, have a bad habit of using words that are not easily understood or recognized by the general public – and that’s a bad thing. Well, I think it’s a bad thing anyway, since the general public are the ones buying the tile – Hello, McFly??? Take for instance those three ridiculously nondescript words up there: Honed, rectified, and gauged – as well as the word ‘nondescript’. Okay, we’ll leave the last one out of this discussion.

Taken alone they each have very distinct meanings – easy enough. However, when used next to the word tile or stone, they tend to confuse. So I’m gonna try to clear it up a little bit for you so you know what a gauged slate is when you see it, as well as help you find the word you need when you know what you’re looking for but don’t know what word you need. (Is anyone else dizzy right now? No? Just me? okay…)

Honed

Honed is used next to different types of natural stone – most commonly with slate – as in ‘honed slate’ (didn’t see that coming, did you?) Although most common with slate it is also used with any natural stone product available. Honed stone simply means that the surface of the stone, has been ground to a smooth, flat, consistent surface. It also means, in the case of normally shiny stones such as granite or marble, that the polish or shine has been removed leaving a matte (unpolished) surface.

If you think about a slate tile (and honestly, who besides me, does that?) with its rough, textured, uneven surface, that would be an example of regular slate – not honed. If that slate tile were ground down with a smooth, consistent, flat surface it would be honed. Just like the tile installed in this Full Kerdi Walk-in Slate Shower with a Mountain Silhouette Relief  installed by Roger from Tile Art in Fort Collins, CO – TileArtCenter.com.

That, by the way, was an absolutely shameless plug for a very excellent tile contractor – me. See, when I self-promote I don’t jack around. Unabashed self-promotion aside, that is a photo of honed slate installed on a shower wall. See how flat and unshiny it is – honed.

That was relatively painless, wasn’t it? Which brings us to our next obscure word…

Rectified

Rectified is a term most often used with manufactured tiles such as porcelain as in, you guessed it, ‘rectified porcelain’. Natural stone tiles are rarely clarified as rectified because they normally are.

Rectified tile means that each tile is identical in size – length and width. As in each 12 inch tile is actually 12 inches – exactly. And each one is identically sized. Or, more accurately, if each 12 inch tile is exactly 11 7/8″ wide, they are all exactly 11 7/8″ wide. The ’12 inch’ part isn’t the important part – the ‘identical’ part is.

What is the difference between a rectified ceramic and porcelain and one that isn’t rectified, you ask? Glad you asked. A normal (non-rectified) ceramic or porcelain tile is formed and baked. This baking process will cause the tile to shrink ever-so-slightly and each tile may shrink a differing amount. This will lead to tiles that are not identically sized. Although the difference in tiles may be only 1/64″ or smaller, if you run a row 25 feet down a floor you may end up with a total 1/2″ difference overall.

Now this is not normally a problem and is dealt with as you are setting the tile by nudging each tile to where it needs to be to make up for this difference. If done correctly you’ll never know it’s there. It’s completely normal.

A rectified tile, on the other hand, is baked then cut to size. All the shrinking will take place during the baking process so after it is cut to size it will remain that size – forever. This makes it much easier, quicker and cleaner to work with and allows for a smaller grout line than may be required for a non-rectified tile. All rectified tiles are cut to an identical size. This is the reason that natural stone tiles are not referred to as rectified – they should all be cut to an identical size during the manufacturing process.

So, if you want really, really small grout lines and an absolutely straight, unvarying grout line, rectified tile or natural stone tiles are the way to go. They are so much easier to keep layouts consistent and lines exactly where you want them. Easier, in this respect, is relative since I prefer the smallest grout line possible with any given tile. The slate shower you see above has 1/16″ grout lines on the wall – this is nearly impossible to do with a tile that is not rectified. You simply have no room in the grout line to make up for inconsistencies in tile size.

*Note: not all slate tiles are rectified! Slate is the only (common) natural stone tile that is not normally rectified unless specifically stated.

Gauged

Gauged stone is a bit more difficult to explain inasmuch as there are a number of things or descriptions of what constitutes a gauged stone. In the most common usage it simply means that each tile is an identical (or nearly so) thickness. This attribute, however, may also be referred to as ‘calibrated’ stone.

Technically gauged means that the backside of the stone has been ground down to a flat, or more accurately, consistent, rough finish. Going back to slate (since there are so many variations of slate stone it is the easiest example) it means the backside of the slate has been ground down to a flat, normally grooved, surface. This process makes each slate tile nearly (if it is calibrated) an identical thickness – usually within 1/16″ or so.

With most stone tiles this is not really a designation you need to look for – unless it is slate. Most all other natural stone tiles (granite, marble, etc.) are cut to an identical thickness. Slate is the exception because, for the most part, it is meant to have a natural, rough, uneven surface. If you want that – don’t be concerned with a gauged or calibrated designation. If you want tile like that shower wall – it needs to be gauged and calibrated.

So there you have it – the three obscure words badly explained in an effort to further confuse you. I do understand that for normal people – that is people that don’t stand in showers all day – there will still be a bit of confusion especially about the whole ‘gauged’ and ‘calibrated’ thing. If you have any questions about it at all please feel free to ask what the hell it is in the comment section below. If you are new to my blog I actually do answer every question around here. I’m just super-cool like that.