How Many tiles do I need??
First you need to figure out the size of the area you are going to cover. Here are some simple formulas.
Circles- .785 x diameter x diameter = inches. divide by 144 to get square feet.
eg. 24" round table = .785 x 24 x24 = 452 square inches /144 =3.14 square feet.
Triangles- .5 x length x width
Rectangles- length X width
Then you need to decide what tiles you are using. 3/4 inch, 1 inch, cut tiles? All of the sizes impact the number of tiles you need. I usually add 10-20% for wastage based on the amount of cutting I am doing for the design.
How do I use Concrete Backerboard? Why?
Cutting- You can easily (ya, that's what the manufacturer says!) score it with a box cutter (Exacto knife) for squares/rectangles etc. Circles are a little harder, require more elbow grease and patience. Just keep scoring and breaking pieces off OR you can use a carbide blade for a jigsaw & cut it that way. (messy, uses a lot of blades but I prefer it!)
Adhesive- Use thinset mortar mixed with an admix as the adhesive for concrete board. (or any concrete-ie birdbaths) I find it reasonably difficult to use the direct method (glue each individual piece) with Thinset so I either do the indirect method on craft paper or the mesh method & then lay the whole piece in at one time. You CAN go direct with thinset it is just messy. Only
mix up a little at a time though because it goes off fast. (I use a little throw away clear plastic cup to see that all of the powder is mixed). I also use the thinset to fix up all the less than perfect edges of the concrete board.
Why use it when it is such a hassle? Do you want this piece to go outside? In our Canadian climate we have NO CHOICE for materials that we put outside. Exterior grade ply is ROT resistant, but in mosaic we worry about expansion and contraction. ALL wood will expand or contract in extreme weather, breaking your lovely mosaic piece.
The easiest way to use backerboard is to get a thin piece and screw it from THE BOTTOM (important that the screw heads be on the bottom) to a piece of exterior grade ply. Concrete board has little strength of it's own and will bend (and break your mosaic) with support. THEN, in a few years when your board has rotted away you can just unscrew it and screw in a new piece. Voila, exterior & strong. Often though table bases and the like HAVE enough support for it on it's own. GOOD LUCK!
What is the MESH method?
So glad you asked! The mesh method or double direct is a great replacement for the indirect method in many situations. It allows you to work directly over your design (rather than upside down) which is very helpful when using materials like ceramic where the colour is only on the surface.
It is also good for installs. Why sweat over the backsplash, floor or fireplace when you can sit at your worktable glue the pieces to the mesh and then install the whole design at one time?
How do you use it you ask? Draw your design out on craft paper. If you will need to move the piece around tape it to a light weight board otherwise tape it to your worktop. Then, place a layer of plastic sheeting or cling-wrap over your design and tape it down (this stops the glue being used to hold the tile to the mesh from sticking to the craft paper design.) Then place your mesh overtop (again taping each layer down so your project does not move). Start cutting your tiles and glueing them to the mesh. I use Weldbond glue as my adhesive. Any PVA NON-water soluble glue will be fine. Put only a SMALL amount of glue on the tile to hold it to the mesh. When you install the mesh you want your adhesive to grab the tile, not the Weldbond. Then once your mesh design has dried prepare your install surface with the appropriate adhesive using an appropriate size notched trowel for the tiles you have chosen. Stick your mesh down, if a few pieces fall off during installation it's not a big deal..just stick 'em back in! Use a board (not your hands) to push it in to keep it level and then let it dry. Grout as usual!!
What do I use to make an outside table?
Outdoor tables are a bit tricky, especially for us here in Canada. If you want to leave it out year-round the only real option is concrete board. I cut a piece the size I need & then screw a piece of exterior grade ply underneath it for support. Screw from the outside in. This way if the board does rot you can remove it and screw in another piece to support the mosaic. The only adhesive that is suitable for tables outside is thinset mortar. I find it difficult to work with in the direct method so I always use the indirect or mesh methods when using thinset. That is me. I am wierd.
For three season tables I use a product called Crezon or Armorboard. It is a signboard used by the government for street signs. It resists expansion & contraction unlike real wood. Prime it really well & be sure to bring it in in the winter. The good thing with Crezon is that it cuts like wood. So much easier than concrete board! I only use Weldbond as the adhesive for this stuff!
How do I cast a garden stone?
This is an easy and great method for perfectly flat garden stones. Create your mosaic by laying sticky paper like Mactac face up over your design. Cut and place your tiles UPSIDE down. This is an indirect method which means you need to be looking at the bottom of the tile. The top of the tile is stuck to the mactac.
Prep your mold with a release agent (I use Vaseline). Lay your completed mosaic in the bottom & sprinkle a fine layer of sand between the tiles (but less on the edges) to inhibit the movement of concrete passed the sticky paper & on to the face of the tiles. Brush the sand OFF of the tiles into the spaces. Sand left on the tiles will inhibit the adhesion of the concrete. Mix sand mix concrete as per manufacturers instructions. There are 2 types of concrete. Sand mix & gravel or pebble mix. ALWAYS use sand as the gravel will rise to the surface & affect your mosaic design.
Pour concrete into your mold to the halfway point. Cut chicken wire or mosaic mesh to fit to the mold (slightly smaller is better) and push into the concrete. This will give it strength (since it is sand mix it needs all the help it can get). Pour in the rest of the concrete. Ensure NONE of the chicken wire is sticking out as it will eventually rust & break your stone. Gently tap the sides or agitate the concrete to remove bubbles. Let dry then pop out of the mold. (I usually wait 3 days…spraying with water during that time to ensure it doesn’t dry too fast). Clean ‘er up and admire. Depending on the weather (like if it is smokin hot out) I would spray it with water again and put it in a plastic bag in a cool spot in the basement to cure slower. That will ensure your stone is strong and not brittle. Check the mfc’s instructions…cure times vary by brand).
How do I grout??
How you grout can make or break your mosaic artwork. A good grout job can make a so-so mosaic look great, likewise a poor grout job can ruin the best tile job.
Grout colour is important. It frames you mosaic. If in doubt pale grey or almond almost always work well. Look in books or online for pieces with your tile colours and study the artists’ grout choices to get a better understanding of the different ways things can look. Grout can be purchased coloured or light colours can be made with by adding acrylics, latex, or pigments to white grout.
What kind of grout? ALWAYS SANDED. Period. Full Stop. See the Q&A list for the reasons why.
How much grout? Estimate 1.5 - 2 cups of dry grout per sq. foot but it really depends on how wide your grout spacing is and how deep your grout joints are. (Always use powder…premixed grouts are unsanded and useless).
I usually waste grout but prefer that to stopping in the middle of a project to mix more.
How do I mix it? Place grout in the bucket and add water a little at a time. It is REALLY easy to add too much water so go slow. It should be wet enough to spread easily, but not runny (peanut butter or oatmeal consistency). Mix well then allow to sit (slake) for 5-10 minutes (NO LONGER),then re-stir thoroughly. I mix grout a little thinner for very porous tiles like ceramics & old dishes (which draws more water from the grout) and thicker for glass-on-glass projects that won’t absorb any water or if it is really warm.
How do I apply it? With gloved hands or a rubber float spread grout over the surface. Rub into the spaces while taking as much off the top as possible. Feather the grout from higher to lower surfaces.
Wait 10-15 minutes until you see the grout starting to dry on top of the tiles. Remove the grout from the tile surfaces with a dry-damp sponge (wring as much water from it as possible first). Only a haze should remain. This is also when you get those grout lines looking the way you want…sponge the entire surface gently once after digging out your tiles and the sandy texture will disappear.
Relax again for another 10 minutes or so. Once the grout haze appears (longer for glass-on-glass), buff surface with DRY cotton cloth (no terry-cloth) and then polish each tile again. Should you notice any low spots or holes additional grout can be added with no problem at this time. This also the time to take the tape off of your mirrors, shells etc to make sure the grout is the way you want it BEFORE it completely dries.
To seal or not to seal…..
I only use grout sealers for areas that are prone to staining such as countertops and tables, trivets, trays etc. Use any grout sealer from the hardware store. Follow the directions and reapply regularly!
Rona carries a grout sealer called AquaMix that needs to only be re-applied every 5 years.
For a glass-like finish you can try an epoxy resin (see the mosaic tools page for information).
What grout should I use?
I always use sanded tile grout. Unsanded is for spaces less than 1/8th of an inch (usually walls) and is difficult to work with, cleans up poorly and sinks if you use it with wider grout lines. Sanded is stronger, easier to work with, can go outside and will not look sandy or scratch the heck out of your tiles contrary to some opinions.
Check out the how to grout part to get advice on doing it the easiest way!
How do I clean grout haze?
If grout haze is difficult to remove or you find a lot of grout has settled in the cracks of your vitreous glass, you can use vinegar to remove it! This is also effective if you started talking to your mom long-distance and forgot to buff your tiles after sponging them.
This should be done the day after grouting although it will still work several days later to remove haze.
Use a nail or toothbrush. Dip in straight white vinegar and scrub the tiles. Leave them wet with vinegar for several minutes and then scrub again. (This gives the vinegar time to work). Wash well with water (to stop the vinegar from continuing to work) and then buff dry. Voila.
Clean and Shiny!!