Mosaics can be applied to practically any surface including bowling balls and styrofoam forms. Your choice of base (backer / substrate) is critical in ensuring that your mosaic project lasts the test of time. The choice of base is determined by a number of factors, including the type of project, intended location and use, cost and your individual choice. Durability and aesthetics are key factors that need careful consideration. Here are 5 factors why your choice of backer is critical:
1. Moisture is a Mosaic Killer!
Where mosaics are exposed to moisture you need to ensure your base is up the challenge. Moisture causes some bases, like wood, to expand and contract. This movement will ultimately break the adhesive bond and crack the grout, leading to tiles eventually falling off.
2. Flexibility is not Necessarily Your Friend!
While we would all like to be more flexible, flexibility in your mosaic base is definitely not your friend. As a general rule if there is movement or flex in the base, do not use it as it will result in the the adhesive and grout cracking. You can solve this problem by using thicker materials, coating the substrate in a rigid material (like fibreglass or cement based adhesive) or using a different material altogether.
3. Begin with the End in Mind When it Comes To Weight
If you are making a large mosaic, like a wall mural, you really need to think about the overall weight before you begin. For larger scale mosaics the weight of the base, tiles, adhesive and grout can be significant. Considerations in the early stage can include choosing a lighter substrate, using the mesh method when creating the mosaic or make your mosaic in sections.
4. Think about How You Plan to Finish the Mosaic Before You Begin
Year's ago I helped a friend make a mosaic table, the actual mosaic looked fantastic (apart of the table edge). The only problem was that we didn't consider how the edge of the table should be finished. It was a wooden table with rounded edges, and not knowing how to finish it we just ignored it. Problem is that over time the grout broke away and the tiles loosened or fell off. If we had of considered this at the beginning I would have tackled the whole project very differently or chosen a different table to begin with.
5. Make Sure Everything Is Compatible
The mosaic can be compromised if the choice of backer and adhesive is incompatible. In some instances the bond may be compromised from the beginning, like stryofoam and harsh adhesives.