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How to Install Mosaic Tile

Mosaic tiles are an unexpected and eye-catching addition to any interior design. Whether you are interested in learning how to install mosaic tile backsplash or how to install mosaic tile over an entire wall or floor, this step by step guide has everything you need to know.


Tools You'll Need

  • Work Gloves
  • Small tooth trowel
  • Two buckets
  • Level
  • Chalk or pencil
  • Tape measure
  • Grout float
  • Grout shaper
  • Caulk gun
  • Tile nippers
  • Electric saw or hand grinder with tile blade


How to Install Mosaic Tile

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Prepare the Surface

While the smaller tiles that make up the mosaic will be more forgiving of a gradually sloping substrate, such as the floor of a shower, it is still important to ensure the surface you're tiling onto is clean, dry and flat. Patch any holes or cracks. If the surface beneath the mosaic tiles is too uneven, those imperfections may start to cause the tiles themselves to look unevenly spaced. In wet areas like bathrooms, shower surrounds or kitchen backsplashes, use a backer board or waterproofing membrane.


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Plan the Layout

Measure the area where you will be installing the mosaic tile. Using these measurements, dry lay the mosaic sheets to plan the layout, accounting for any cuts needed around outlets or edges. Mark your layout lines on the prepared surface using a level and straightedge. This plan will help you determine where to lay your first mosaic sheet as well as how the edge tiles will need to be cut.


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Cut the Mosaic Sheets

For most tile sheets, you should be able to simply cut the mesh backing between the tiles. To cut the mesh backing, flip the tile sheet so the tiles are facing down and cut the mesh using a utility knife.

Cutting mosaic tiles themselves can be a bit trickier. But with a little bit of patience, the process is not much different from cutting other tiles. Start by marking where each tile that needs to be cut using a marker. Then, take a pair of tile nippers and carefully nip each tile to size.


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Mix and Apply Thinset Mortar

Mix the thinset mortar according to the manufacturer's instructions. Only mix as much as you will be able to use within about 20 minutes to prevent the adhesive from drying out before you are able to apply it.

Using the notched trowel's flat side, spread thinset mortar onto a small section of the prepared surface, following your layout lines. The grooves created by the trowel notches will help ensure proper tile adhesion. Work in small sections to prevent the adhesive from drying out.


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Install the First Mosaic Sheet

Carefully determine the center of your tiling surface and mark it with a pencil or chalk. Press the first mosaic sheet and gently onto the thinset, aligning it with your layout marks. Gently tap the tile sheet with a grout float or a flat piece of wood to ensure even adhesion and to make sure the tiles are all sitting flat and even across the substrate. Use a level or a straight edge to ensure the tiles are even and aligned.

If your tiles aren't pre-spaced on a mesh sheet, use tile spacers to maintain even gaps. Periodically check the alignment and level of the tiles as you go.


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Add the Remaining Sheets

Continuing to work in small sections, spread the thinset and apply additional mosaic sheets. Be careful to align the edges of the mosaic to maintain a seamless appearance between sheets. Leave a 1/8 inch expansion gap where the tile meets any other surfaces such as countertops or walls.

Allow the thinset to fully cure according to the manufacturer’s directions before grouting.


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Mix and Apply Grout

Using a clean bucket, prepare the grout following the manufacturer's directions. Aim for a consistency similar to peanut butter. Mix only as much as you will be able to use within 20 to 30 minutes to prevent the grout from drying out before you are able to use it.

If you are grouting mosaic tile on a wall, start from the bottom and work your way up. If you are grouting a mosaic tile floor, start at the point furthest from the door and work backwards.

Using the rubber grout float held at a 45-degree angle, work the grout across the mosaic diagonally, carefully filling the spaces between the tiles. Wipe away excess grout with a damp sponge. Keep a bucket of clean water on hand for rinsing the sponge and change out the water frequently to make sure it stays clean.

Allow the grout to dry for 15 to 30 minutes and then remove any excess grout using a grout shaper. Once you are finished, allow the grout to fully dry as specified by the manufacturer, which usually takes 24 to 72 hours.


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Clean, Seal and Caulk

After the grout completely dries, buff the tile surface with a clean, dry cloth to remove any grout haze. Once the tiles are clean, apply a grout sealer to protect the grout from stains and moisture.

After the manufacturer’s specified grout drying period, using a caulk gun, fill the expansion gap with caulk. This will add an extra layer of waterproofing and create a more finished, professional look.


Mosaic Tile Installation FAQs

  • What is the best adhesive for a mosaic tile backsplash?

    Thinset mortar is generally considered the best adhesive for mosaic tile installations. Thinset cures to a very hard and durable state, creating a strong bond between the mosaic tiles and the substrate. This ensures the tiles stay securely attached, especially in high-moisture areas like bathrooms and kitchens. Thinset can also be used with a wide variety of tile materials, including ceramic, porcelain, glass, and natural stone, making it a universal choice for different types of mosaic projects.


  • Are mosaic tiles easy to install?

    Mosaic tiles typically come pre-mounted on a mesh backing in sheets, which is significantly easier to handle and install. With the right tools, mosaic sheets may be easier to install than other tiles because they cover a much larger surface area, typically one square foot.

    Even mosaic tiles that have an irregular pattern are quite easy to install. Although the tile placement may look random, these mosaic sheets are very meticulously designed to interlock with one another, allowing for a seamless mosaic across large surfaces.

  • What are the disadvantages of mosaic tiles?

    While mosaic tiles are a popular choice for many design styles, there are some unique challenges to consider.

    Higher maintenance. More grout lines mean more potential for grime and mold buildup, particularly in wet areas like bathrooms if not properly sealed and maintained. Regular cleaning with the right products will keep your mosaic tile installation looking its best.

    Replacement challenges. If a single tile within the mosaic chips or cracks, it can be difficult to address the individual tile, especially if it is mounted on a mesh sheet. Removing the tile without damaging the surrounding tiles will be a more delicate task, although with a little care it is a job suitable for novice home renovators.

    Grouting. More tiles means that more grout lines are involved due to the small size of the tiles, which can make the grouting process more labor-intensive and require more precision to get a clean, uniform look. However, achieving this does not require a special skill set, it just requires patience.