Clear Coatings For Mosaics?

Texture and three-dimensional elements make two-dimensional art much more interesting. Having thicker pieces and pieces that stick out make people want to reach out an touch your mosaic. Why would you want to cover that up with a material that scratches easily, can’t be repaired and turns yellow with age and sunlight?

Even if you do need to cover the mosaic somehow to provide a level surface, there are usually other means of doing so that don’t involve permanently coating the mosaic with these relatively short-lived materials.

My Mosaic Is A Table Top

Most mid-sized towns and cities have a glass shop where you can have a sheet of glass cut to a custom size and have the edges beveled (smoothed and rounded) with a torch. This same shop will also have small rubber pads for sitting under sheets of glass, and you may be able to use these for holding the sheet above your mosaic. If the surface of your mosaic is fairly rough and irregular in height, then you can use larger rubber stoppers and other means of holding the glass above the surface of the mosaic (such as a rim around the table).

I have seen some wonderful mosaic tabletops that were made from all sorts of found stones, shells and artifacts and then covered with a sheet of glass that rested on rubber stoppers. The overall look and feel of the table was like one of those curio coffee tables that have the glass tops over artifact collections, only the artifacts were closer to the glass cover, more visible and seemed to be part of the surface, which they were.

One important caveat: Make sure that the mosaic is evenly supported in multiple places and that no one piece of the mosaic can make contact with the glass if heavy objects are placed on the table. Otherwise you could possibly crack the glass.

My Mosaic Is A Floor

In general, I do not recommend making floor mosaics from materials with different thicknesses due to the potential for them to be a trip hazard and to be damaged by shoes and wheels and vacuums. If you do want to use material of variable thickness in a floor mosaic, make sure you do something that results in a level surface.

Consider Using Mortar Instead

One option is to press these pieces into a bed of thinset mortar similar to how crafters press tile into wet concrete to make garden stepping stones. However, be aware that mortar thins as it cures, so there is only so much height difference that can made up for by mortar when a tile is much thinner than the tile around it. In our studio, we solve this problem by mixing small pea gravel into the mortar underneath the particularly thin tile. We also have thin pieces of stone tile that we coat on both sides with thinset mortar and use as shims under thin pieces. Note that these methods aren’t really practical for large areas or commercial jobs.

Clear Epoxies For Floors

There are epoxy products that will last a long time by standards of flooring and architectural products, but I tend to think in terms of archival standards for fine art and making things as intrinsically durable as the Roman aqueducts. If you put a epoxy clear coat over the top of the mosaic, then you need to carefully review the manufacturer literature on the packaging and Internet. You want to look for information concerning scratch resistance and hardness and durability. You will also want to review the manufacturer’s recommendation for maximum recommended thickness.

Epoxy Not Polyurethane

If you do use a clear coat to make a level surface over a mosaic made from irregular pieces, then make sure you use an epoxy and not a polyurethane. Polyurethanes are not as hard and scratch-resistant as epoxies. They also do not bond securely to glass the way epoxies can.

How To Find Epoxy Clear Coats

These will not be in the tile aisle of the building material store. They are sometimes in the flooring department, but they are more often in the paint department. The important point is that they aren’t specific for mosaic or tiling, so don’t expect them to be sold for that purpose. Also, you should not expect professional installers to know how epoxy clear coats might be used to cover tiled surfaces, at least not in a thickness significant enough to compensate for differences in tile height.

Problems With Clear Coats For Mosaic

  • They cannot be removed or repaired by practical methods.
  • Installation is not very forgiving. You may have bubbles and haze that cannot be fixed.
  • They are not inexpensive and usually cost more than the mosaic tile.
  • They are not commonly used on mosaics, so professional installers don’t have experience with them as far as mosaics are concerned.
  • They scratch easily compared to porcelain, glass and most stone.
  • They turn yellow in ultraviolet sunlight, some much faster than others.
  • They won’t last the millennia that glass and stone mosaics are capable of lasting.

108 responses to “Clear Coatings For Mosaics?”

  1. I am interested in mosaicing an old window with clear stained glass. My goal is for the colors from the stained glass to throw color into my little nest. Is this possible keeping the backside attractive where the adhesive would be? Would epoxy be the best kind of adhesive to use?

    • Most people use a white PVA adhesive such as Weldbond for glass on glass mosaics. However, it can take quite a while for the glue to dry and be completely translucent when sandwiched between large pieces of glass.

  2. I just finished doing a mosaic on a concrete bench for outside. After I seal the grout lines I would like to put a clear coat of some kind on it. Is that OK?

    • I covered an existing turtle with small broken floor tiles along with a few other type mosaic tiles and I want to seal it for outdoor protection. What is the best sealant to use to prevent damage from the weather?

      • We aren’t brand loyal. We usually use TileLab brand tile and grout sealer from Home Depot, but any silicone-based pore sealer will work.

    • Yes, but you need to attach the tiles with thinset instead of adhesive so that the water doesn’t make them pop off over time. I wrote an article about mosaic bird baths.
      I hope this helps!

  3. I’m doing some mosaic inserts in some concrete benches. What can I use to seal the tile and grout and not reveal the tiles sharp edges? Clear sealer of some type?

    • Doug,

      Grout or thinset mortar needs to hide sharp edges, not a sealer. Sealers are thin applications the seal pores. I have used small rounds pebbles of a fine-grain stone (found outdoors in different regions of the country) to smooth rough edges between tile when the grout didn’t hide them. The fine side of a marble file such as we sell can be used on outside edges, but it can’t fit between the tile. A small round stone can be dragged down the length of the grout gap and dull any sharp edges higher than the grout.

  4. I finished a stained glass mosaic art piece. I included resin peacock feathers
    that I made. I just finished grouting the piece and the resin feathers are not
    level. Could I use ice resin to level them off?

    • Ann,
      I suppose you could, but we are unfamiliar with resin. We only use archival materials and methods.

  5. I did a “mosaic” of small gravel, some tinted with acrylic paint. It is a butterfly in center of a small round table. The butterfly sections are framed with a soft round rubber. It is surrounded in crushed sea shells. The rest of table top is done in thin pine strips, herringbone pattern and stained with minwax in Honey color. I have not sealed the stain yet. The mosaic has a layer of mod poge over top. I tried to keep the gravel as level as possible with the height of strips. I would like to seal it all with something to create a clear, level finish that is resistant to scratches and water stains. Can you suggest something?

    • I’m not sure what would be compatible with the modge podge and minwax stain and other materials. It sounds like a glass top on rubber feet might be the way to go. I hope this helps,

  6. Dear Joe: Hi! You have a lot of knowledge here! Thank you! I inverted a glass and mirror tile design on tape and want to put it on top of a wooden box. A lot of the tiles are cut with sharp edges so until I read your blog, I was going to totally cover the tiles with epoxy. This is new to me so I am learning: here is what I have gathered as possible steps: 1. Sand and scratch wood and Seal wood with Weldbond (Weldwood does not hold mirror tiles well but seals wood well). 2A. Glue tile images down (tile images are inverted onto thick celephane type tape that I don’t think will stick to dried epoxy– meaning even if 2B is possible, if the epoxy touches the tape, the tape can be removed after the epoxy dries), glued on top of the dried Weldbond with E6000 OR; 2B. Put a 1/16″ layer of epoxy mixed with Faux Granite-Mauve color (1 part epoxy, 1 part Faux Granite– cool texture look!) over the dried Weldbond and while wet add tile images on the tape so that the colored epoxy seeps up into the 1/16″ to 1/8″ spaces between the tiles, and the Faux Granite then becomes like a grout look. However, I don’t know what kind of epoxy resin to purchase for glass and mirror tiles or if any epoxy resin will hold the mirror and glass tiles down so I am worried about 2B– originally I was going to add clear epoxy resin over this 2B and over all the tiles until I read your blog. I have tested E6000 over the dried Weldbond on wood with my tiles and it is super strong. But I prefer 2B if it is possible because I like the Faux Granite look. I don’t think I can pour the “Faux Granite” colored epoxy resin over the top of the tiles after I glue tiles down with E6000 and remove the tape, because over the top of the tiles might cause too much “Faux Granite” color over the tiles and not just in the spaces between the tiles. 3. If 2B is not possible I will need to grout over the tiles glued with E6000 with colored sanded epoxy grout, I think, one compatible with mirror and glass tiles. Originally I thought I should epoxy over the whole tile image after removing the tape that is over the tile images and after grouting one way or the other because of the many sharp points on the cut 3/8″ glass and mirror tiles. But if grout is sufficient, I think your suggestion is best, to avoid epoxy over the tiles themselves. Can one file the glass or mirror tile point if the point is exposed after grouting? I really thank you for challenging my plans. I have a lot to learn! Becky

    • For mosaics that need extra strength, such as a mosaic on a chest or box, you can use thinset to grout or one of the new epoxy-based grouts. They are stronger than regular traditional grout. Filing clear glass mirror tiles is problematic. Regular vitreous glass tile and recycled glass tile can be filed with the fine side of marble file, but clear glass must be filed more gently because it tends to flake and scratch more, and the flakes are more visible.

      I hope this helps,

  7. Hi there ๐Ÿ™‚

    I have a mosaic picture mounted on plywood that I want to turn into a garden table. I don’t want a glass top and it has to be waterproof. Any idea how I go about this?

    My first thought was epoxy clear coat, or do you have a better idea?


    • Hi Fred,

      For a mosaic to be durable in a wet or humid environment, the first step is to chose a backer and cement that are appropriate. It is very difficult to start with an existing mosaic on plywood and make it durable, but I would use marine varnish/water seal to thoroughly seal the sides and bottom. I would use at least 3 coats, and I would pay close attention to the sides. The face of the mosaic isn’t as vulnerable, but it still needs to be sealed as well.

      I hope this helps.

      • This is interesting for my wifes project. We have used marine grade plywood and it is sealed for the weather. The mosaic work, glazed tiles, is quite intricate with very narrow and irregular grout lines.

        Is there a sealant that protects both the grout and the tile, while still maintaining the tile glaze? Or should we apply the seal over everything and then wipe it from the tile a few minutes after, so the sealant will have had time to absorb into the grout? We are fearful of the tile being discolored by the sealant.


          • Thanks again – another interesting article. My wife was familiar with the problems with marine grade ply and had already planned on only hanging the works for summer months. Where we live we’re pretty dry with steady humidity.

            Thanks also for advice on sealant. Interesting to learn that, when we went to local hardware store, who don’t carry a lot of grout sealers anymore, that most grouts today are presealed. We’re a bit hazy on that but was wondering if you had much experience with the presealed grouts?

          • Hi Eric,

            I’m not familiar with the pre-mixed epoxy and urethane grouts. I suspect those don’t need sealing. Traditional grout requires sealing, and the Tile Lab brand Tile and Grout sealers from Home Depot are invisible pore sealers, and the basic version doesn’t change the gloss of the finish or provide gloss because they aren’t coatings.


  8. I have a mosaic that was produced overseas to a client’s specs. and now some of the individual pieces have fallen out. The attachment method used to adhere the pieces to the substrate is unknown. The mosaic is mounted vertically to a wall. Is there a clear substance that can be applied to the surface of the piece that will keep the individual pieces of glass in place should one or two come loose from the substrate? The coating should keep the pieces together as a unit. I realize this could mean the whole thing could come loose and fall off the substrate but the client is willing to gamble on it. The mosaic cannot be laid flat to allow epoxy to cure the way it could if this was a table. Can you recommend anything? Thanks!

    • Hi Dave,
      We can definitely help. You might be making this more challenging than it really is. You can cement the tiles back into place and use a small piece of clear packing tape to hold the tile in place until the cement cures. The only real issue is to make sure you use a glue or cement that sticks to what is already there. You can test this by pressing a dot of adhesive onto the substrate and allowing it to harden thoroughly and then scraping it off.
      I hope this helps!

  9. I have a mosaic picture of a lady witth necklaces and bracelets raised above the surface of the mocaic tile. Can I use resin or polyurethane to properly cover the varied levels. It doesn’t have to be level because it is to be hung on the wall
    Many thanks, Lizzie

    • Hi Lizzie,
      The jewelry was raised to give the surface of the mosaic interesting texture, and so I’m not sure why you would want to cover that up, especially on a vertical surface that is decorative. At any rate, the coatings are thin and won’t cover elements that protrude with any significant depth, and so they wouldn’t be effective. I think you should keep the mosaic as is and enjoy the textured elements.
      I hope this helps.

  10. Hi Joe,, I have done a mosaic of a woodland scene on a bevelled wood board, The problem I have is in parts of the mosaic I used glass frit which usally bonds in a kiln, it’s in different textures , this frit very close so I cannot grout it , it is glued on the board . Would you just leave the part with frit and grout the tiles , I did think of epoxy resin also , but want the feel of the glass , Do you think I should leave all of it or part grout. .?

    • Hi Jennifer,
      Indoor mosaics do not have to be grouted, and so if moisture isn’t an issue, anything to make it look right is acceptable. I can tell you that grout tends to overwhelm and cover small chips, and so I would probably leave it ungrouted.

    • Hi. I am also in the beginning stages of doing a multimedia pottery and Frit bar top mosaic. So many details. Irregular pieces, different textures, and glass Frit for the shore lines. We want to do an epoxy top coat to level it out and protect it. Looking for more information about the process and what products to use. Any suggestions?
      Malissa Loyd

      • Hi Malissa,

        The guy who wrote the article explaining why those products are a bad idea probably isn’t the best source of a recommendation. ๐Ÿ™‚

        I would go to a paint store and building material store and ask them which is the best for UV-resistance in terms of yellowing and cracking. I would look those products on Amazon, Home Depot, and other retailers so that I could read the reviews.

        The most important reviews are the negative ones, and you can usually tell which negative reviews are real issues and which are just written by trolls and people who didn’t follow the directions.

        Please email us pictures of the finished work.

        I hope this helps!

  11. I made my first ever glass mosaic top lazy susan, i did not think to smooth the edges of the glass peices before gluing them down. I attempted to sand the edges before grouting but apparently it wasnt enough. I ended up with several cuts on my hand after grouting. I need to put a clear coat of something on it so it wont be dangerous. Any suggestions would be appreciated. Thanks

    • I have seen people put pieces of glass over the tops of mosaics with sharp edges. A local glass shop might be able to cut a circular piece and supply some rubber feet/pads.
      I hope this helps.

        • I would love to see how your project turned out. I JUST finished tiling (mosaic) over an outdoor tabletop. Thinking about pouring clear epoxy to smooth it out. Iโ€™d love any tips you have? And what epoxy you used? Can you share?

  12. Do I only need to seal the grout on a glass mosaic lazy susan?
    Does it need to be specifically food safe?
    I’d like to use it as a platter server … Cheeses, dips etc.

    • A tiled and grouted surface isn’t an FDA approved food surface, but it isn’t toxic either. If you want to use it as a serving platter, have your local glass shop cut a piece of glass and put that over the mosaic (with small pads).
      I hope this helps,

  13. Hi,
    I have been advised by a mosaic teacher to seal my mosaic indoor wall hanging with a polyurethane clear sealant. After reading online comments about sealing, I am torn about whether this is a good idea or not. My first project was sealed with rust-oleum clear gloss sealer and the whole thing is very shiny. Can you advise on this? Seal or not? And if so, what product is best. Keep in mind this is indoor art. I understand outdoor is handled differently.

    • No coverings, but sealing with a marble enhancer would be the recommended treatment for unpolished tumble-finished marble.

  14. Hi Joe,

    I realised my black grout on my mosaic piece always left my hand stained even after the finished piece of mosaic art is completely dry after grouting. Pieces sold in the shop with black grout don’t seems to have that issue. Do I need to coat it with something after grouting?
    Appreciate your reply

    • Cured grout should not be leaving any sort of residue on hands. Wash and dry the mosaic and see if you still have a problem.

  15. I did mosaic tiling on the riser part of the steps in my back garden and used Bal superflex wide joint grout for grouting. The grout said indoors/outdoors use, suitable for power showers and swimming pools, frost resistant………, I thought it would be the ideal one to use. Three days after i completed the job, we had torrential rain overnight and when I next looked at the mosaic about 2 days later, I noticed a crusty limescale-like film over the surface of all of the ceramic tiles. Is this a substance that came out of the grout or did it come from the stone slabs on the steps? My question is how do i prevent this from happening everytime it rains? One person has recommended using an epoxy based resin over the mosaic and grout on the risers, but I’ve just been told by a technician from Lithofin that might not work . He said i should coat the stone steps and the risers with Stainstop W. Please could you give me your opinion on this.
    Best regards,

    • Hi Stephen,

      It sounds like it was just the normal lime shed by relatively new grout. That problem should stop after a few rains/washes unless the grouts wasn’t mixed with sufficient water or allowed to dry out prematurely before it could properly harden. In that case, no sealing or coating would help.

      Our expertise is in craft and fine art using traditional grouts and mortars, and so we aren’t up on all the different sealing products, but I’m fairly certain that any coating epoxy or otherwise will be prone to the problems described in this article.

  16. About 5 years ago I completed large mosaics on my kitchen and living room floors. I used tile adhesive to hold both the broken plates that I clipped into needed shapes and the broken tile pieces I used throughout. I grouted with a charcoal non-sanded grout. Everything has gone very well over these 5 years except that the grout has dulled and small bits are coming up in some places. What can I use to seal the grout so it won’t look dulled after a few years and hopefully it won’t come up? I would like the grout to pop rather than be so bland. Because of the colors I used with the plates I have no problem with those colors popping. Thank you.

      • Thank you so much for the information. Because the kitchen and living is mostly mosaic – approx. 24×15 and most of the grout is sound I think I will take up the unstable grout and then seal it. Trying to find the right sealer is very confusing. The information on the containers aren’t very detailed. So, thank you again for being very precise.

  17. Dear Joe,
    Thank you for the most comprehensive discussion on the topic of mosaic protection!
    After inspiring trip to Pompeii, my cousin (an academic sculptor) took a task of making a nice classic mosaic for the entrance to my Bar. We have chosen an Octopus, and it came out magnificently, with just over 10000 pcs, all natural stone, onyx eyes, size just over 3 by 6 feet.
    It is fixed on the base of Kerabond, sintetic flexible plaster, of some 2 inch depth. Face is very nice and quite even surface, with only natural irregularities of small stone pieces protruding.
    Now, it will be placed on the floor, surrounded by old stone rough floor slabs, on a very busy entrance area – to be lit nicely, visible and stepped on all the time.
    The big question is – how to install it:
    1. As is – Under a thick luxurious protective (walking over) glass, with a discreet led lights around;, or
    2. Flat with the surface of the floor, level with the floor, lit naturally with spot light from above…- to be walked on directly (semi-open area) ….
    If option two, what do you suggest as the best, durable and most discreet protection, against accidental red wine spills for example, and other staining ??
    I prefer minimum intervention to retain authenticity, as the place is an ancient Roman excavation site on the Mediterranean…. Where historically, mosaics have been used in areas to walk over them, directly.
    I am afraid of altered final looks if I use epoxy, I don’t want it to look “modern” and shiny, when lit….. anything that you might think of, it will have to be a very thin layer to keep the moisture (and staining of the stone) out, and to keep it’s natural look. Any suggestions?
    I can send you photo of it, if you prefer….
    Many thanks ๐Ÿ™‚

    • Hi Igor,

      Thanks for the kind words and definitely email us some pics.

      How thick is the stone? In a busy entrance way, soft stones such as “honey onyx” will wear down quickly. Depending on the traffic, even a harder marble could be worn down or gouged, especially in a restaurant with acidic foods and cleaners and impacts and abrasions.

      In this situation, I think I would use the glass over the top, especially if I could have lighting around the rim that makes the octopus appear under water or like a window to an excavated floor of a much older building or something like that.

      Here is what we used last for a sealer:

      I hope this helps!

      • Dear Joe, thank you very much for your prompt reply!

        The idea of fixing it under glass, with a discreet rim led light sounds attractive and we are seriously considering it..
        There are, however, 2 problems with it:
        1. The glass has to be very massive, heavy (and expensive), one piece of course (cca. 20 sq. foot), in order not to bend and to be safely set up- on rubber around the edge to make distance between the glass and the mosaic, etc.. So once done, it will most likely be like permanent, non removable setting.
        If it is so, and we thought of fitting an LED discreet light around and under the rim edges, it might look very nice. But what if the LED light fails, changing it would be like doing the whole set up from a scratch. Or else the glass would have to be fit into some kind of tight fitting (metal?) frame, so the glass can be removed if needed. Sounds quite complex and anywhichway we choose, rim/LED light installation/frame/ glass would to some extend visually impare the mosaic/stone harmony…
        One way or the other, there would have to be a visual break up between the mosaic and the stone- not ideal.

        2. We want it to be prominent, as a centerpiece and attract passers by from the street. If it is set under glass, even shallow below the floor level, I’m afraid that it will not be readily seen by passers by from the street, plus inevitable reflection from the glass…..

        Original idea was to set it up directly on the floor level, with centraly focused light from the ceiling, rough stone slabs around it… and to apply over it best possible protectant. Thanks for the “Miracle Sealant”

        recommendation, “511H20 Plus Sealer” sounds like optimum solution.
        We feel it will be more authentic that way – most ancient Greek and Roman mosaics have traditionally been installed on the floors too, within walking areas and we prefer to keep that authentic looks !

  18. I would like to make special memory stones that can remain outside. I would appreciate your suggestions on what would be the best materiality put over it to keep items from loosening over time and fading.

    • Tile is made from mineral pigments that are UV resistant if not permanent. This article discusses sealing finished mosaics with a tile and grout sealer.

  19. I am making 4.5 glazed ceramic tiles with a uv printer for art wall decorations and would like to exspand this art into backsplashes and bathrooms. this art is a high quality print and I’m wondering what I might be able to put over the top to make it waterproof and not lose its clarity

    • For wall art decorations that don’t see abrasion or moisture, you have a lot of latitude and can use anything that will stick to the ink without dissolving it and making it run. The first thing I would try would be artists acrylic varnish.

      I hope this helps,

  20. We did a small sink area in a condo kitchen with mosaic glass tiles. White grout. Now we wanted to make it super safe and easily NON stained….and now we are having a problem finding epoxy that will not dull out the white grout around the gray and white glass. Most say they are clear but than chatting with someone from the company of one, they say it has a natural amber tint. Any way of getting something crystal clear?
    I tried but couldn’t figure out how to send a pic of it!

    • Raeanne,

      We avoid using sealers like that as stated in the article, and so we don’t really know. You would need to visit paint stores and building material stores and talk to people working there. Many of them won’t know much, but others have worked as contractors and in the building trades, and those people are a wealth of knowledge.

      I hope this helps!


  21. I am making a mosaic round side table for outdoor use. What do you recommend sealing with to form a level top that can be used for drinks and such?

    • Nothing that I no of. This article explains why thick coatings for mosaics are problematic. Use a custom-cut piece of glass with rubber feet on it if you need to put something over a mixed-media mosaic to provide a level surface.

  22. I also made a tabletop on a piece of lucite in a class for outdoor use. Our teacher supplied glue that is not waterproof!
    Will sealing it provide enough protection from outdoor exposure?
    Thanks Sheila

  23. Joe – I do Glass to Glass Mosaics using Weldbond glue with an acrylic spray which works great for indoor but for outdoor items not good at all! We have high humidity here and I need some kind of sealer for outdoor projects-what do you recommend? No yellowing on bubbles! Thanks

    • I would ask for non-mosaic sealers at the building material store, something like a deck sealer that is an actual coating, and I would read the product label to find out about UV-resistance.

      I hope this helps!

  24. Hello

    We remodeled our kitchen and took out some cabinets to open it up. My husband did a mosaic on the floor where the cabinets were. It turned out beautiful but it is chipping & uneven and is a pain to clean. Do you think we should use epoxy over the entire mosaic or something else…the biggest problem is keeping it clean as he continued the mosaic directly under the other cabinets where we prepare food. thank you for your time.

    • Hi Debbie,
      This particular mosaic is an architectural covering and not a small mosaic icon that will be handed down for generations. For that reason, a clear coat of epoxy makes sense.

  25. Thanks for all your information!
    I am looking for the best way to seal small mosaic hearts that are made by “students” going through my Beauty in Brokenness program. These hearts are made with thin set, various types of broken tile and beads then grouted with a charcoal sanded grout. Before they are packaged and shared with individuals and families struggling with mental health and addiction, they are cleaned and sealed with a poly spray.
    I have been having issues with our sealing process lately (and frankly the grout seems more grainy than before as well)
    I am looking for recommendations on the best way to achieve a glossy shine to this matte finished grout without continuously costing an arm and a leg (not to mention toxic spraying that does not seem to cover evenly all the time).
    I would really love to have a mosaic process “expert” that is in the Houston area come see what we are doing and make suggestions for process improvement! If you would like to see our hearts, visit

  26. I made a mosaic number for a house .
    Itโ€™s going to Maine. Snow, very cold weather
    I want to put a non yellowing resin over top to protect it form the weather. What should I use?

    • Hi Nancy,

      LOL. This article is an explanation of why we don’t use them and don’t recommend other people use them. If your mosaic is made with glass or porcelain tile, it should be fine with a regular tile and grout sealer, which are invisible pore sealers and not coatings. If you did use soft ceramic or stone, then you would want to ask at the building material store and maybe read a few labels. What you need might be on the paint aisle if it isn’t in floor coverings.
      I hope this helps!

  27. Hi, i just finished a mosaic on top of an iron table. I used flat glass pieces for the mosaic. The glass pieces have a small variation in some of the thickness’s so I’m looking to cover the mosaic with something protective and also something that would level the top. Would an epoxy/clear resin work for this? There is about 1/8″ from the glass tiles to the top of the wall around the mosaic, it will be an indoor table, used as an end table. it’s about 18″ x 24″ and grouted already. i can send a picture of it if that helps!

    thank you!

    • Weldbond would work great- levels – perfectly clears after a while and no yellowing- tile setters use it and that basically what you have but flat- should work great- no toxic fumes either! Indoor only!

      • Hi Daryl,

        I love Weldbond and use it in all my indoor mosaics, but I would never use it as a surface coating on a table for two reasons: It doesn’t have the hardness to resist scratches, and it can soften and whiten when exposed to moisture.


  28. MESSAGE / QUESTION to Joe Moorman – Post Author ( sorry, I do not know where it properly to place !) :

    On small bathroom floor we install Abolos Blue Mosaic 0.25″x 0.25″ Glass Tiles over recommended Instaset Instant Thinset Mortar Mastic Adhesive Roll. It came out not perfect – has some quite wide spaces between mosaic sheets (1/8″). We want to protect the adhesive “base” from water going through the joints. What should we use ? It has to dry clear, not white or yellow. Anything ?
    We would appreciate any help !

  29. I have a round mosaic I bought on an international trip and I will be insetting it into a piece of wood. I would like to cover it with epoxy or a piece of glass. Any suggestions?

    • This article explains why you would want to get a piece of circular glass from a local glass shop instead of using epoxy.

  30. I have a whirlpool built from concrete. It is cladded with mosaic throughout. What clear product would you suggest to completely seal the mosaics bearing in mind they will be permanently under water.

    • I would seal it with whatever concrete sealer is recommended for pools. The package labels have recommendations, suitability for use info, etc.

  31. Hi there!
    I recently covered a patio table with a mosaic. Its ceramic tile (mexican hand painted and a few bathroom styles) and glass gems (both full size and pieces). I used a black grout and left a decent amount of space between tiles for the look I wanted. Should I use a thompsons water sealer or would an epoxy work better on top to level things out and make it waterproof ? I’d like to be able to eat on it. Haha also, I live in LA so we are pretty dry but get rain a couple months out of the year. It will be under an umbrella of course.

    • This article explains why clear coatings such as epoxy are a bad idea. I would use a tile and grout sealer or a concrete sealer. Thanks.

  32. Since this was written, ArtResin created a product with a different additive that unlike every other epoxy out there, actually doesn’t discolor. There are multiple articles out there about how this is the only epoxy to use outdoors, and my mosiac is currently at about 1 year in the CA sun with zero discoloration. Highly recommend checking it out!

    • I would still be concerned about discoloration in 30 or 50 or so years from now. We try to recommend only archival methods and materials.

  33. Hi…I am not an artist but tried my hand at making a mosaic out of left-over floor and wall tiles. It’s 4’x4′ with a plywood base, plain wood frame made with standard framing board, and I set the tile using “Simple Grout” pre-mixed adhesive and grout from Home Depot. I also painted some of the larger areas of grout. The mosaic will be outdoors spring through fall, laying on a wood base to keep it off of the ground a bit. I would love to seal it (as all of the tiles are not the same height) with something that’s self-leveling. I thought of self-leveling epoxy but would like to know if there’s something else you recommend? Some of the tiles are glazed since they are standard wall/floor tiles. Thanks!

    • Hi Karen,

      I’m not familiar with those because I don’t use them, but I’m thinking that even the current clear epoxies will fail like the old ones that have cracked and yellowed over the years. The good news is that the epoxy should last as long as the plywood backer. You should paint the devil out of the sides and back of the plywood with a few coats of oil-based paint to prevent it from swelling with humidity.

      I should clarify for people skimming the comments that traditional grout doesn’t have the adhesive properties of mortar and glue and cannot be used to mount tiles. I suspect the polyethylene grout you used was probably sticky enough.

      I hope this helps.

  34. Hi Joe

    I can’t find the answer to a small problem and wonder if you could please advise?

    I have just tiled an inset recess above a washbasin with mosaics on a backing sheet. They comprise of glass, natural stone and a few are silver metal.

    I have grouted but need a sealant around the bottom where they meet the basin. Could you please recommend something? Would PVA do?

    I guess as this is just in a cloakroom I may get away without sealing the while thing but what would you recommend?

    Thanks in advance for any help.



  35. Last Summer I purchased a mosaic console table for my deck outdoors. I didn’t realize I should have put some kind of protection on top of it. It is Winter now and I see that the tiles have begun to crack from the extreme temps and a lot of precipitation. I’m considering just throwing away. Is there any kind of epoxy I could apply over the surface to seal it after the fact? I appreciate any response. Thank you!

    • We don’t really use the general-purpose coatings because these yellow and crack with age, particularly in UV light.

      If you still want to use them, they will be in the paint and coatings department of the building material store probably and probably not in tile or flooring. I would read labels and reviews and pick one based on UV resistance.

      I hope this helps some!

    • Clear silicone such as GE Silicone II is the recommended adhesive for glass-on-glass. Don’t apply too thickly. Thin is best.

  36. I made a large (2.5×2.5 ft) indoor sun mosaic using glass,ceramic and frosted tiles- 35mm on plywood and gluing it on with Wellbond. Can I leave it ungrounded? If do, do I need to use a sealer? Thx so much. It took me a long time to complete and I want to finish right. Robin

    • Hi Robin,
      Dry indoor mosaics that aren’t table tops or some other functional surface do not have to be grouted or sealed.
      Please email us pictures of your work.

  37. Cement All iron oxide stained peacock mosaic. 4 ft. By 6 ft. Gonna put in driveway.
    Question: Can you recommend an epoxy with low yellowing, high impact, scratch resistant. EI plan to make the epoxy surface thickness about 1 1/2 inches. Presently, mosaic in about 1 to 1 1/2 inches thick without epoxy of any kind. Keracolor US grout used. Mosaic placed in polyflex thin set. Peacock sealed with 511 penetratin sealer.

    • I doubt any clear coat will stick to a sealed mosaic. Epoxy in a driveway would get scratched. The blog post explains the other reason epoxy is a bad idea.

    • A regular mosaic sealed with a tile and grout sealer from the building material store is perfectly fine as a table top.

  38. I have a mosaic kitchen table. when you look at it in a certain light it looks like the surface has been splashed with something and doesn’t wipe off – it looks like it has been sealed with something and is in the sealant. is there anything I can do to repair this?? when you look at the table over head it isn’t visible

    • I suspect it was a spill of something like bleach that etched or reacted with the clear coat. It was either that or some problem with how the clear coat was initially applied.

      The only solution I can think of is to research what stripper could be used to remove the clear coat.

      I think that situation with your table is another reason to avoid clear coats for mosaics. ๐Ÿ™

  39. Okay, like an idiot I didnt think this all the way through. I used Weld Bond to adhere mosaic tiles to a white mailbox. My intentions were to actually USE the mailbox. That’s where it stands. Where do I go from here to protect it from the elements and to ensure the tiles don’t pop off?

    • Hi Rod,
      I understand completely. I was working an engineering job which required me to design hand tools and manufacturing processes, but when I made my first mosaic, I came home and chipped my tiles using a claw hammer in the most inefficient way possible. Something about the drive to make art causes people to think only about the aesthetics of what they are making and forget all other concerns.

      A clear coat might be a way to make the project last a lot longer. Find one for outdoor use that resists UV damage.

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