Backers: Info and Ideas

Choosing a backer is very crucial to the success of your mosaic project. Being familiar with your choices in backers will help you achieve the desired result you want with your mosaic piece.

Backers, bases, substrates, all refer to the same thing – what you will mosaic on. Backers should be non-flexible surfaces so there is no bending which can pop tiles off. They should also be made with the right materials for the environment your mosaic will be in. Do not use materials that will decay when placed outdoors.

Porous bases like terra cotta pots, wood, MDF, etc., should be sealed. You can use a mix of white craft glue and water to seal them before you mosaic. If not sealed, you run a risk of your tiles popping off since the base will absorb the moisture from your adhesive and weaken the hold. Keep in mind that wood eventually will decay. I do not recommend using wood in any type of outdoor mosaic at all.

Backer boards (Skeewbackers), ceramic, stone, wedi board and cement bases are great for outdoor or wet areas as well. Cement backer board is another choice for outdoor projects, although it is very heavy and harder to cut. Always start with a clean surface and make sure your base will be able to support the weight of your tiles, adhesives and grout.

QuikStik Mosaic Mesh is a fiberglass mesh which is a great way to work on a project in your studio, off-site. You place it over your pattern, place your glass onto the sticky fiberglass mesh and then you can adhere it to your backer. It is ideal for large mosaics that may need to be cut into sections for transporting or installing. Be careful of the fiberglass as it can irritate your skin so gloves are advisable.

Styrofoam is another fun material to use as a base. You can sculpt it or buy it in shapes like a ball. I like to apply a thin layer of thinset and then while it's wet, cover it with fiberglass mesh to give the Styrofoam extra strength and durability. Then I use thinset to adhere my tesserae to it.

So try different backers; but consider all the variables in order to make the right backer decision.


  • I am really appreciating the info you share here! AND seeing all the materials available! Wow! My first mosaic I glued onto rug hooking mesh, then cut it into 3 sections and mounted straight into thinset on the wall. You can imagine the difficulties! That was 20 years ago and I was totally unaware of anything like the sticky mesh you sell! And Wedi board! When I learned about wedi board I tried to order a full sheet cut to various sizes for mosaics. The venders seemed to have a hard time imagining how I intended to use it. I’m glad you are here.

    Amy Aspell
  • Trying to use thinset for very small pieces on a large project. May we use weldbond to hold the pieces down on the mesh until we apply the mesh to the wedi board with thinset,

    sue kramer
  • Clear and useful information – thanks so much!

    John Sollinger
  • You do not have to use mesh on Skeewbackers. Just glue your tesserae directly to the board using the right kinds of glues. You can use weld bond, thinset, any adhesive that does not have any “ethyls” in it or any solvents. Because of the foam core center, any solvent will warp the boards, and that is what happens with E6000. Do not use E6000. Also, spray paints will harm these boards. But you are safe for interior mosaics with using weld bond; for exterior mosaics thinset works great.  Just be sure to check ingredients.

    Lou Ann
  • So can I use this skeewbackers WITHOUT fiberglass mesh and apply my tesserae directly to thin set spread over the backer board?

    Katherine Jivery

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