Mosaic Street Number Plaque

Mosaic Letters and Numerals

You can make mosaic street numbers and signs using a grid, but mosaics made from irregular shapes of non-gridded tesserae are more interesting, especially if you use concentric andamento for the background surrounding the figures.

Sara Sommers emailed us some pictures of her mosaic street number plaque, and it is made from cut pieces of tile in strongly contrasting colors. It is definitely worth checking out if you are thinking of making a piece with large mosaic letters or numerals.

Contrasting Colors

For starters, Sara uses strong color contrast between her numerals and background, which is critical for making eye-catching art. She also uses multiple related colors and variegated patterns instead of solid monochromatic color fields.

Variegated Colors & Patterns

The numerals are made from yellow and orange colors of our Irregular Glazed Ceramic Tile, and the background is made from our china-patterned Glazed Porcelain Tile mixed with some of our Morjo™ 12mm Recycled Glass Tile in dark midnight blue. For added visual interest, the numerals are outlined in cut pieces of Morjo™ in a lighter blue color.


Traced Outline Mosaic Numerals
Traced Outline Mosaic Numerals

Sara started by drawing some outlines of the numerals she wanted to mosaic. You could use stencils for this purpose or even the numerals and letters sold in craft stores as improvised stencils and then return them.

Consistent Spacing

Early Version Mosaic Numerals
Early Version Mosaic Numerals

In the picture above, notice the extra-large spaces between some of the tiles in the numeral “2” and compare that to the revised numeral “2” in the picture below.

While grouting can “pull things together” and help make separate pieces of tile represent a solid figure, it can’t help inconsistent spacing of tile. In fact, grouting usually makes inconsistent spacing look worse. If you have larger gaps in places, those will stick out like a sore thumb when they are filled with concrete, especially if they are in a focal point, such as a face or the eyes of a face.

Appropriate Backer for Outdoors

Mosaic Numerals Revised
Mosaic Numerals Revised

Since this mosaic was going to be mounted outside, it was critical that it be made on a backer that wasn’t vulnerable to moisture and humidity, instead of plywood, which eventually warps and deteriorates outside. Also, thinset mortar is used instead of mosaic adhesive to mount the tiles.

Prevent Freeze Damage

I should note that even though the glass and glazed porcelain are non-porous and frost proof, the Irregular Glazed Ceramic is relatively soft and vulnerable to freeze damage and isn’t ideal for outdoor use. To prevent water from seeping into microscopic holes in the glaze, it should be sealed with multiple applications of a tile and grout sealer purchased locally at a building material store. (We don’t sell sealers at our website because they are ruined if they freeze during shipment.)





11 responses to “Mosaic Letters and Numerals”

  1. Lyn Richards Avatar

    Thanks for this article, Joe. It confirms what I’ve been doing on a hunch. I use tile concrete backer board for mine, thin set mortar, and all glass tiles. I cut my board using a jig saw, and then I can get unconventional shapes. I’ve found that I only need the 1/4” backer board, which can be scored and broken into squares and rectangles. I’m still trying to work out the logistics of building an obelisk using backer board and treated lumber.
    This is a lovely design!

    1. Joe Moorman Avatar
      Joe Moorman


      That is a good point about the 1/4-inch concrete backer board. It is easier to cut than the 1/2-inch board, and you can always cut out two copies and then laminate them together with thinset mortar if you needed something thicker.

  2. Mary Frederickson Avatar
    Mary Frederickson

    I learn so much from your newsletters! Thank you. Mary

  3. Gail Gueno Lewis Avatar
    Gail Gueno Lewis

    Your newsletters are soooo informative, Somehow I ended up on your email list and very happy that I did. Keep them coming. Thanks!

  4. Sasha Avatar

    Hi! We have created mosaic numbers to label our garden beds at our camp. We had kids help with this process and they turned out great! We made them on Hardy Backer. I am having a hard time figuring out how to mount them to our garden beds, which are made from redwood. Is there an adhesive that would work? I guess we could have drilled holes but unfortunately I didn’t think of that ahead of time. Any suggestions? I really appreciate the help!

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Sasha,

      I think a construction adhesive such as Liquid Nails brand should work.

    2. Lyn Richards Avatar

      I have successfully used a picture hanging “loop” that I’ve attached to the backer board with super glue and 1/4” screws (very short). Then I used picture wire between the loops and hung the backer board by the wire, just like a picture.

  5. Erika Avatar

    Did you prep the Hardie Backer board in some way before adding the tiles? I am doing a mosaic on harrdie backer and using thinnest to attach the tiles The project will be outdoors but under an overhang. I applied thinnest to the tiles but as they dry they are popping off the surface. Any thoughts? I did not do anything to the backer board before applying the tiles.

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Erika,
      I don’t prep or seal the board beforehand. It sounds like the board soaked moisture from the thinset while it was trying to harden, or you might have used old thinset that had already ruined by absorbing moisture from the air over time. I always spray down cement and concrete board with water so that it is damp inside before I mosaic. Thinset, grout, and other portland cement products harden by bonding water and will not harden properly if allowed to dry out.

  6. Debora Avatar

    Hi Joe,
    Your information given is so much appreciated especially to someone like me that has never done mosaic. I am wanting to mosaic a tile pattern on my metal mailbox. I’m wanting to make this last for a long time due to hot and cold weather. Will the thin set mortar be the best product to use and will it adhere to the metal mailbox? Also what would be the best type of glue for this project to glue the tiles on?
    Thank you for any information you can give me

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Debora,
      Yes, people have used thinset mortar to attach tiles to metal, but I think it requires a thicker layer than normal to make sure the mortar can tolerate the slight movement and thermal contraction/expansion of the metal. For this reason, I think GE Silicone II might be more robust for this application. The key is making sure that you don’t put it on thickly because it is compressible and flexible when hardened.

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