Ask the Builder: DIY mosaic tile? You can do it
![This is a small section of a huge mosaic tile floor in an airport. The tip of my shoe provides scale. (Tim Carter/Tribune Content Agency)](https://thumb.spokesman.com/uO6q6eDqVn9RLDznlEJuDvMVKgE=/600x0/media.spokesman.com/graphics/2018/07/sr-loader.png)
Q. Tim, I need your guidance. I want to do a large mosaic tile floor in my new room addition. I have no clue where to start. I’ve never done tile work before. Do you think I’m crazy for attempting this? If not, what can you share to ensure success? I don’t want to goof up and have to rip it up. There will be some heavy furniture on the floor. Is that an issue? – Rebecca T., Tuscon, Arizona
A. Who doesn’t love an eye-popping, drop dead gorgeous mosaic tile floor? It’s possible for a beginner to lay a mosaic tile floor as a DIY project, but, as with many things, you need to take baby steps first.
Mosaic tile is a blend of artistic skills and tile craft. I’ve seen mosaic tile installations that make my eyes hurt because they were poorly thought out or the installer/artist rushed the job. Let’s unpack the project by splitting it into two parts.
Let’s discuss the artistic aspect first. I’m not an artist, but I know enough to realize that a mosaic tile scene can be abstract or represent something you would recognize. For example, you might be trying to create a mosaic of a mountain scene at sunrise. It could be a mosaic of a flower or a pet. There are countless things you might try to re-create using small colored pieces of tile.
Having never done this before, you should start small. I’d try to create small tile mosaics that measured maybe 2 feet by 4 feet. That gives you enough real estate to create something that you might recognize or something abstract.
An artist might start with a scale drawing of the design with all the correct colors and shading. Choose something simple. Don’t try to recreate the Last Supper on your first try. This would be the dealbreaker for me because I’m only halfway decent at drawing stick people. You, however, may have an artistic bent. If so, you should follow it!
Using your color drawing as your north star, gather pieces of tile that are all the same thickness and begin to cut and snip them to the correct small sizes that you’ll need. If you’re a digital person, try to imagine that each small tile is a pixel on a smartphone or tablet screen image. You can also visit websites that have countless photos of finished mosaic tile pieces to grasp what you need to do.
You’d do well to lay the cut pieces of tile next to one another on the floor making sure you allow for a grout line that might be as narrow as ⅛-inch around each piece of tile. You can use tile nippers to shape thin tile. Beware of using porcelain tile on your starter project, as it’s extremely hard and very difficult to snip and shape. Use a softer tile with a traditional clay core. These snap with ease.
Once you have your mosaic design created and you’re happy with how it looks from 5 or 10 feet away, most of the difficult work is done. All that’s left is to install the tile and grout it. Be forewarned that installing individual pieces of mosaic tile is a challenge. But don’t worry, you’re going to do it, and it will come out fine.
Floor tile must be installed in thinset, fine silica sand mixed with Portland cement. It’s what mice would use to build brick homes. Thinset allows the mosaic tile to bond well to a solid subfloor. Once the thinset is cured, it’s almost as hard as a rock, and it doesn’t move. Organic tile mastic that’s like thick cake icing is never to be used to set floor tile. It can move, and the tile will crack.
The secret to installing the mosaic tile is to match the size of the tile to the trowel that will be used to put down the thinset. If your mosaic tile is about the size of a postage stamp, let’s say 1 inch by 1 inch, then you need to use the smallest notched trowel you can find. Most certainly a ⅛-inch by ⅛-inch square-notched trowel would be in order.
Hold the trowel at about a 30- to 45-degree angle as you spread the thinset on a piece of cement board you’re using for your experiment. Get the cement board damp with water before spreading the thinset. Only put down as much thinset as you can cover with tile in five minutes or less.
You have to work fast, especially if you live in a dry climate where the thinset can skin over rapidly. If this happens, the bond is poor between the thinset and the pieces of tile.
Avoid allowing any thinset to ooze up between the pieces of tile. Remove any ooze immediately, making sure you don’t smear it on the face of the tile. The top of each tile must be in the same plane, so place a small piece of smooth perfectly flat plywood on the tile and lightly tap it so the tops of the tile are all in the same plane.
Use sanded grout to finish the job. Watch my four “How to Grout Floor Tile” videos at askthebuilder.com website to see how this is done. Be careful: If you use too much water, you can ruin all your hard work.
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