There are numerous really cool mosaics and liners which can be installed as an accent into your main field tile to add a unique touch to an otherwise standard tile installation. These are products such as glass and natural stone mosaics, individual painted tiles, or custom accents.
The biggest problem with these, however, is they are oftentimes not the same thickness as your main tile – they are usually thinner. This is especially true of most glass mosaics. I usually solve this problem with Schluter Ditra. Although I use ditra as my example in this post, you can also use regular 1/4″ backerboard if your inserts are significantly thinner.
See that glass (and metal) mosaic right there? (Photo 1 – You can click on it for a size larger than a small dog) It’s setting inside the main linear mosaics I’m installing on a backsplash. See how much thinner it is than the surrounding tile? That’s what we’re gonna fix. When you have your tile installed you want it all to be on the same flat plane without either tile sticking out (or sinking back). The best way to do this is to have an additional substrate behind your thinner tile to bump it out flush with the rest.
You want to cut your ditra about 1/16″ smaller than the overall size of your insert. You want to make sure you have enough support behind the insert, but you don’t want it larger. (Photo 2)
In Photo 3 you can see where I’ve flipped the ditra upside down so the fleece side is out. You want to install your insert onto the fleece side rather than the plastic, dovetailed side. this is much easier, especially with smaller tiles, and gives the insert more adhesion on the backside once installed. The thinset will ‘lock’ it to the wall doing it this way.
Photos 4 and 5 show how the ditra bumps it up to the same height as the field tile. If your insert is a LOT thinner, it may be better to use the 1/4″ backerboard, although you can double-up the ditra to make it thicker.
Once you get your ditra and inserts cut to size (cut all of them at once) get your thinset mixed up and cover the entire fleece side of the ditra inserts. Make sure the entire surface is covered, most mosaics are fairly small and any uncovered areas may lead to just one or two pieces not being adhered well. Spread it just like these here:
Then place your inserts onto the ditra and press down slightly – only slightly! Before you firmly press the inserts and the ditra together you want to flip them upside down. Doing this ensures that the face of your inserts, the shiny part that makes people go ‘ooooh, pretty’, is completely flat. Flipping them upside down, then pressing down firmly, will get the entire face totally flat and get a full bond onto the ditra. It is always best to use a flat surface on the back, squeezing them between the flat surface and the flat countertop or bench – whatever your wife lets you use. Like these:
Once you get them all installed to the ditra, flipped, and pressed down firmly to ensure a full bond – leave them alone! Give the thinset at least three hours to cure and get a grab, ideally let them set overnight. Really, leave them alone. Stop staring at them. Go have a
beer Pepsi and have some dinner. We’ll get to them later.
Once the thinset is cured you can fill the dovetails with the flat side of your trowel, then comb on the thinset with the notched side and install them into your design. You can cut your main field tile with spaces large enough for your insert (don’t forget the measurement for the grout line around the mosaics). And tile away. When you’re finished you should have two different tiles, with different thicknesses, installed flush on the same plane. Like this here:
This method works for backsplashes, shower walls, even tile floors. As long as you have good contact with the insert to the ditra, and good contact behind the ditra to the substrate, you should have a nice, flush tile installation which makes people go ‘ooooh, pretty’. Like these here: