Mosaic Stepping Stone Instructions

Mosaic stepping stones are great first projects, but they don’t have to be cheap and cheesy or dangerous. Keep in mind that if you totally cover the surface of the stone with large pieces of stained glass, it is likely to be slippery when wet. If you leave sharp edges of glass exposed, or allow the grout to erode out from between the glass over time, then your stepping stone is less of a stepping stone and more of a device for cutting bare feet. Both of these problems can be avoided by following best practices and using sound methods.

A Brief Rant

First, avoid the craft kits that have you make a butterfly or some other canned 1970s design by gluing large pieces of pre-cut stained glass onto a stepping stone. Glue will not resist moisture over time, and these kits are the poster child of slippery when wet. They also look exactly like all the other mass-produced stepping stones from China and thus have all the charm of a fast-food wrapper or billboard.

Instead, make something original by pressing your own designs of small tile into wet concrete, and be confident that whatever skill you lack may actually add to the originality and charm of what you make. A homemade stepping stone is supposed to look like a homemade stepping stone and not something made in a Chinese prison factory based on a design first copied in the 1970s.

Glass Tile Is Best

Glass tile doesn’t have any pores, and so water can’t penetrate into it and freeze and crack it. Ceramic materials have lots of pores, and there are tiny cracks in the glazing, so these materials are more susceptible to freeze damage. However, porcelain and dinnerware and other high-end ceramics are a lot more resistant to freeze damage than something like glazed bathroom tile, so they can be used with discretion. Remember, the more soft or crumbly a ceramic material is, the more susceptible it is to freeze damage. Avoid terracotta, glazed ceramic bathroom tile and anything that easily breaks.

Decide Which Method To Use

There are two main methods of making a mosaic stepping stone. It is better to use a mold if you are wanting to use marbles or large stones or other found objects not easily attached to a flat surface.

1. Prefabricated Stepping Stones.

You can cement tile to a plain prefabricated concrete stepping stone purchased from a lawn and garden center.

2. Stepping Stone Molds.

You can press tile into wet concrete in a stepping stone mold or have a mosaic design on contact paper at the bottom of a stepping stone mold and pour concrete on top of that.

Note that both methods require that you mix up a powdered concrete product because you cannot use glue to attach tile to an outdoor or wet mosaic. Instead, you have to use thinset mortar, which is a powdered portland cement with polymers added for enhanced adhesive properties and strength.

Prefabricated Stepping Stones

Plain concrete stepping stones can be purchased from lawn and garden centers. These make great bases for mosaic stepping stones even if you are wanting to press tile into wet concrete instead of cementing the tile to a rigid surface and then grouting later. How is this possible? Easy. You simply spread the mortar on a little thicker than normal, say about 3/8 inch thick, and press the tile into that.

Stepping Stone Molds

Stepping stone molds can be purchased or improvised from ordinary containers such as plastic dish pans and old metal cake pans from the thrift store. Various websites recommend using the nonstick baking pans from your kitchen and even make the claim that you won’t scratch them up, but I wouldn’t go that route. As a general rule, I avoid using anything from my kitchen in my art studio and then returning it to the kitchen, and I’m fairly sure that some people would manage to scratch the pan when they removed the hardened concrete stone. Besides, you can always get old cake pans from the thrift store or use a plastic dish pan or take an old plastic 5-gallon bucket and cut it down with a jigsaw. There is no reason to raid the kitchen when all these other options are available.

Tip: No matter which type of mold you use, make sure you coat it with non-stick cooking spray or petroleum jelly (Vaseline) to ensure that the hardened concrete stone can be removed easily.Sources of Improvised Molds:

mosaic stepping stone instructions
A stepping stone mold with some accessories. The pea gravel can be mixed with the thinset mortar to give it strength and bulk.

Sources of Improvised Molds:

  • plastic dish pans
  • plastic totes
  • purchased stepping stone molds
  • old cake pans from thrift stores
  • 5-gallon plastic buckets cut down with jigsaw
  • plastic litter boxes (new or bleached)
  • plastic plant trays
  • cardboard boxes lined with plastic trash bags
  • your spouse’s nonstick baking pans (not recommended)

Two Ways To Use A Stepping Stone Mold

There are two ways to use a stepping stone mold. You need to decide which you will use, and the second is better for marbles and other found objects that aren’t flat like ordinary tile:

1. Put the tile at the bottom of the mold and pour concrete over that.

You can place your tile UPSIDE DOWN in the bottom of the mold and pour the concrete on top of that. The easiest way to keep your tile from moving around when the concrete is poured on top is to put contact paper at the bottom of the mold with the sticky side up. Then you stick your tile UPSIDE DOWN onto the contact paper. This method is recommended if you want a very detailed design because it allows you to get all your tile carefully positioned before you mix up the concrete, which only has a few hours of working life before it starts to harden. Even if your design isn’t very complicated, I wouldn’t attempt it without the use of contact paper. Make sure you add the concrete slowly and gently tap the mold as you go along to make air bubbles come to the surface.

2. Press tile into wet concrete at the top of the mold.

This method is best for mixed-media designs made from marbles and other rounded found objects that couldn’t stick reliably to a piece of contact paper. You simply press the objects into the concrete, and you have the advantage of being able to vary how far they are embedded and to see how the work looks as you go along.

Tip: Wait 30 to 45 minutes before you start pressing objects into the wet concrete. This allows the concrete to firm up a little so that your objects don’t sink to far into it.

Using Thinset Mortar Instead of Ordinary Concrete

Thinset mortar mixed with a little pea gravel is MUCH stronger than ordinary concrete.

Most stepping stone instructions say to use ordinary concrete and often have tips about how to pick or sieve the larger pieces of gravel out of the concrete so that they don’t interfere with the tile or objects you want to embed in the concrete. One of the most significant hazards of doing mosaic work is breathing concrete dust, so if you were going to do this sieving or picking, you would want to do it AFTER you had mixed the concrete up, and that seems like a lot of pointless and difficult work to me.

Instead, I buy thinset mortar, which does not contain gravel, and I mix in small pea gravel in a ratio of 2 parts wet thinset to 1 part pea gravel by weight. For example, to make two small stepping stones, I recently used 8 pounds of wet thinset mixed with 4 pounds of pea gravel.

The pea gravel is needed because thinset mortar slightly contracts as it cures (due to the adhesive polymers), and all traditional portland cement products need and aggregate such as gravel or pea gravel to provide tensile strength.

IMPORTANT TIP: Set some of your thinset aside and don’t mix any pea gravel into it. Use this gravel-free thinset for the layer where your tile will be embedded so that no gravel interferes with the tile as you press it in. First, fill your mold about 3/8 inch from the top with the thinset mixed with pea gravel. Then fill the rest of the way up with the plain thinset. That top layer is where you would press the tile without having to worry about pea gravel in the way. If you have a pattern on contact paper at the bottom of the mold, you would first pour in some plain thinset and then top the mold off with the mixture of thinset and pea gravel.

Tips for Using Thinset Mortar

I have written some instructions for using thinset mortar and some tips for keeping your hands and tools clean while working with thinset mortar.

My instructions in those two links are for doing very detailed work with thinset. Most mosaic projects (such as stepping stones) are a lot more simple. Most of what you really need to know about thinset can be summarized here:

  1. Wear a dust mask when mixing up thinset to avoid breathing dust, and mix it up outdoors for easy clean up.
  2. For Versabond brand thinset, we mix 1/4 pound of water per 1 pound of thinset. The package will have manufacturer instructions for how much water to mix in.
  3. You have about 2 to 3 hours of working time provided you keep the thinset covered when not in use. If you are working in conditions of extremely dry air, such as when the heater or AC is running), then use a humidifier to keep the air moist.
  4. Do not dispose of thinset in plumbing or drains. It is concrete and can harden underwater.

Cleaning and Sealing

No matter which method you use, you should wait at least 24 hours before removing your stepping stone from the mold.

Sometimes stepping stones made on contact paper at the bottom of a mold will be removed from the mold, and the artist will discover voids between the tiles due to bubbles. Other times, you will see that concrete has gotten between the tile and the contact paper, and so there is concrete on top of the tiles. Both of these problems are easily fixed.

Voids are filled by mixing up small amounts of concrete and dabbing them in. Concrete on top of tiles can be scraped off using a small screwdriver or other steel tool. Use a spray bottle to mist the stone as you work to control any dust.

A few days after your stepping stone has hardened, you should seal it with a tile and grout sealer from a building material store.






54 responses to “Mosaic Stepping Stone Instructions”

  1. Issa Parker Avatar
    Issa Parker

    Great advice and hints! Very glad I found this site.

    1. madeline austin Avatar

      thank you for all this advice. I am working on a cement slab about 15′ by 25′ I’m putting glass mosaic down. It is an outside porch, with a roof. I think the thin set is what I need to use thank you for sharing so much info.

      1. Joe Moorman Avatar

        Yes, I think you do need to use thinset. Even if there isn’t any direct exposure to rain, the changes in humidity and temp can age adhesives over time.

  2. […] Note that here I am talking about using thinset mortar to attach a mosaic design to an existing stepping stone or paver or flagstone. If you need instructions for how to use a stepping stone mold to press tiles into wet concrete (or pour wet concrete over a mosaic design mounted on contact paper at the bottom of a mold), then read my article on Mosaic Stepping Stone Instructions. […]

  3. Jen S. Avatar
    Jen S.

    Thank you for a helpful and thouogh guide. I can’t wait to begin!

  4. stone sample boards Avatar

    Thanks for posting such a good blog having very helpful information.

  5. Karen miller Avatar

    I can’t use thinset. What other glues or adhesives can I use for outside stepstone8

    1. Joe Moorman Avatar
      Joe Moorman

      Any construction adhesive that might be capable of lasting will have fumes and toxins and be messy to work with. Why do you need to avoid thinset?

      1. Karen Avatar

        I find it difficult to spread and it eats on my hands

        1. Joe Moorman Avatar
          Joe Moorman

          Yes, many people find it necessary to wear rubber gloves, especially if working with mortar for an extended period or day after day.

  6. Karen Avatar

    How difficult is it to press stained glass into wet mortar using store bought concrete step stone. How much time do t have before it sets? Thank you

    1. Joe Moorman Avatar
      Joe Moorman

      It is very easy. You have a couple of hours in the bucket, but once you spread it, you need to press on the tiles within 5 to 10 minutes tops. Working time is very much affected by how dry the air is.

      1. bennie hobson Avatar
        bennie hobson

        How many cups of mortar do I use per mold.
        How many cups of concrete per mold.

        1. Joe Moorman Avatar
          Joe Moorman

          That depends on the size of the mold. I would have to mix up some concrete and test, but I don’t think it would be much different from how much dry concrete or mortar it would hold because the water fills in the spaces between the particles of powder instead of increasing the bulk volume. There should not be much difference between the capacity for mortar and concrete.

  7. J bower Avatar

    Can I use white silica sand with thin set mortar is for my stained glass stepping stones? I cut my glass putting glass at bottom of mold.can not find white cement anymore

    1. Joe Moorman Avatar
      Joe Moorman

      White sand won’t make the cement white. You should be able to find white grout or mortar and put pea gravel in it if you really want white concrete.

      I hope this helps!

      1. Sara Avatar

        Hi Joe,

        I would like to make some stepping stones with a black cement filler- what do you recommend doing to achieve that color?



        1. Joe Moorman Avatar
          Joe Moorman

          Hi Sara,

          You would need to use charcoal/black grout for grouting a mosaic made on a pre-made stepping stone or press the tile into concrete dyed black with concrete dye if you are making the stepping stone with a mold.


  8. Elaine Avatar

    Hi is it possible to use 4mm thick glass tiles when using the upside down method for stepping stones. I have a mixture of thin and thick tiles which I would like to use. Thank you

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Elaine,

      If you mean the method where you stick contact paper in the bottom of the mold and stick tiles to it and then pour concrete on top, then yes, that method works very well for tiles of different thickness.

      You can also pour concrete in a mold and press tiles into the top. That method also works well with tile of different thickness.


  9. Cecelia Avatar

    Thanks for all this great information that I will use to make some various sized stepping stones for my garden. I want to seal my stones when they are dry, but can you give me some sort of an estimate on how long it will take them to dry enough for me to seal them?

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Cecelia,

      I usually wait 48 hours, but you could probably seal them in about 24 hours.


  10. Gayle Avatar

    I am just starting out on making stepping stones. I am wanting to know approximately how many cups of mortar mix I need to measure for one 8 inch cake pan size stone? Thanks in advance!

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Gayle,
      I never measure it with cups. I fill the mold with the powdered concrete to see how much I need or I guestimate.

  11. Kim Avatar

    Should you seal your mosaic stepping stone after? So it will last?

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Kim,
      We always seal ours with an ordinary tile and grout sealer from the building material store. Mosaic stepping stones can last a very long time. If you live in a place with cold freezing winters, you can increase their life by bringing in during the winter or cleaning and resealing every few years. Note that you should seal every surface of the finished stepping stone, even the bottom.
      I hope this helps!

  12. Sherry Miller Avatar
    Sherry Miller

    We have a square of concrete that my husband just poured around a septic sewer protect it last week. I have a jar of small pieces of glass that I want to put on this piece of concrete and grout it. Do I need to glue each piece down first or will it hold if I pour outdoor grout and then lay the glass, Let it sit and then scrape off the extra grout that is on the glass?

    1. Natalija Moss Avatar
      Natalija Moss

      This can be done if you use thinset mortar as the adhesive. You could then grout between the tiles with the thinset itself, or regular grout, but it would have to be done as two applications. First application is using thinset to adhere the tiles to the concrete. Second application is grouting the tiles with either thinset or grout.

  13. Nicole Avatar

    Hi! Thanks for the info here. We’re gearing up for this project. I bought quickCrete mortar mix. I was planning to put a piece of hardware cloth in to add strength. Would that have same affect as the pea pebbles? We’re doing 12 in diameter round. Ty!

  14. Blogalina Avatar

    Yours are the best instructions instructions ive found. I’ve made stones in the past, it’s been years. Unfortunately I got a 10 pound bag of mortar and it does not fully fill the form which is like 16 inches in diameter. It’s only a half inch deep. So now I got to go out and buy more I think. Otherwise I’m afraid it will crack.

  15. deborah carroll Avatar
    deborah carroll

    So, with a prefab stone from a garden store, I use thinset as mortar and place my glass. Then, if I want to achieve a stained glass effect, can I grout with charcoal colored grout and do I use sanded or unsanded? Thanks!

  16. Darlene Pashak Avatar
    Darlene Pashak

    I was advised to apply a concrete sealer to my project, which I would call a memory stone. I have glass on it, but some 3-dimensional objects too. The instructions on the sealer say to wait 30 days for cement to cure, but since this is a memory/stepping stone, can I put the sealer on after 48 hours as you have recommended? Thanks for all the clear instructions!

    1. Joe Moorman Avatar
      Joe Moorman

      The concrete is still hardening during that period and needs access to ambient humidity.

  17. Caroll M Avatar
    Caroll M

    I am having trouble getting the Vaseline to wash off of my stepping stones before I seal them. I am using a special white mortar mix that the hardware store recommended. I tried Dawn, Ajax, alcohol, cornstarch, Acetone, hydrogen peroxide, coconut oil, Ivory Soap, baby shampoo and sanding. What do you suggest? The blue Dawn and Ajax left blue stains on my stones. 🙁

    1. Joe Moorman Avatar
      Joe Moorman

      You could try paint thinner.

  18. Shelly Avatar

    Thank you so much for your great instructions! I actually did this project with a class of high school students. We made 11 mosaic stone letters for the school that are roughly 18×24. All of the stones turned out great except 2. I had to leave them on the floor of my classroom to cure and a mischievous student stepped on them while they were in the mold curing. Is there any possible way to join the broken letters back together. Each of them broke in only one place- the middle part of the “H” dividing the letters in half. Any help would be greatly appreciated. I have googled everything I can think of to find an answer, but given this is your project I thought you may know the answer or have run into this issue previously. Thanks

    1. Shelly Avatar

      I forgot to mention in my previous post, we used the thinset mortar idea with pea gravel if that helps. Thanks again!

    2. Joe Moorman Avatar
      Joe Moorman

      Hi Shelly,
      Email us pictures at the website, and I will take a look.

  19. Karen Murphy Rhu Avatar
    Karen Murphy Rhu

    I love your tone and content. I try not to buy supplies from prison factories as well.

  20. Margaret Avatar

    Good evening,
    I am wondering if i am able to repurpose an old garden concrete seat, which original had some type of design, such as mosaic but thinner. I has mostly all chipped away. I am wondering if i was able to remove the remainder which I don’t think will be difficult. My though if i could is to add old china plates to it to make a pattern as they belong to my grandmother to have a memory of her in my garden- were we leave temperatures in the winder can go to below zero- this slat is way to heavy to bring in each season.
    Would there be any material which you could recommend and steps to set and have it last over the winter seasons
    Thank you in advance

    1. Joe Moorman Avatar
      Joe Moorman

      Instead of putting the china on the concrete seat, I would make stepping stones that could be brought in during the winter. Otherwise the project won’t last very long.

      1. Margaret Avatar

        Thank you Joe

  21. C Brun Avatar
    C Brun

    Hi. Are you saying that you can use just thinset mortar for an entire stepping stone, or are you just using it for the top (bottom of the mold) later around the glass? If so, can you say what brand you are using?

    1. Joe Moorman Avatar
      Joe Moorman

      I often use Versabond brand of thinset mortar mixed with pea gravel as structural concrete when I need something to be as indestructible as possible and less water permeable than ordinary concrete. Yes, you could make a stepping stone itself from that concrete, but that would be a separate step from attaching the mosaic.

      1. C Brun Avatar
        C Brun

        Thank you so much for responding! I wanted to ask you, because I went on the product page on the Home Depot website, and someone asked this exact question. The answer provided, (I think it was a builder that responded) stated “No, VersaBond can not substitute white Portland Cement and sand. VersaBond has much more chemical components and it is designed to bond ceramic tiles.”

        I use the indirect method to make stepping stones, so I have the glass in the bottom of a mold, and pour my concrete (I have been mixing my own and am experimenting with different mixes trying to find what works best) over the glass. This works well for me, I can color the concrete too, so I like that. I have no interest in gluing to a premade stone as I prefer my own shapes and I really like the smoothness of the indirect method.

        1. Joe Moorman Avatar
          Joe Moorman

          Versabond thinset mortar contains two things not found in traditional portland-cement grout. The first is ethyl acetate which forms PVA, the same as white glues such as Weldbond.

          The second material is ferrous blast furnace solids. If there is any concern, I think it would be the potential for trace amounts of heavy metals to be in the blast furnace solids.

          I am very conscious of those type risks, verging on paranoid, due to all the exposure I had to toxins as a kid, but I’m not worried about the blast furnace solids in Versabond for several reasons.

          Virtually all of the exposure would in handling and mixing the powdered material, which already requires masks and handling via misting and other dust-control methods. If you breathed enough to pick up trace metals, the silica and caustic dust would have already killed you.

          I also don’t see any association in the literature between workers in tile setting and heavy-metal exposure. Keep in mind those guys are working with industrial quantities of the stuff every day, and they don’t do a good job of dust control.

          The bottom line is that I don’t have any reservations about using it as a grout in found-object sculptures, but there isn’t much incentive to go out of your way to use it in applications where a normal grout or concrete will suffice.

      2. C Brun Avatar
        C Brun

        Yes, I use the indirect method of placing glass in the mold, on contact paper. Then I fill the mold. I bought some Versabond and am going to try a test stone and see how that works.

  22. Eileen Avatar

    What is the best way to finish off the sides of a stepping stone so the mosaic glass or tile pieces will not come off. The technique I was going to use, was gluing the pieces to the top of a premade stepping stone, and then grouting it and of course, sealing it.

  23. Katy Vanoni Avatar
    Katy Vanoni

    HOW in the world does one set the mosaics onto the contact paper upside down? How do you keep the design???

  24. Paula Campbell Avatar
    Paula Campbell

    I am a complete beginner and would like to create a mosaic on a premade concrete paver- thanks for your excellent instructions.
    I am concerned that the paver will be slippery when wet and am therefore confused about the mosaic materials I should use. Will glass be too slippery?

    1. Joe Moorman Avatar
      Joe Moorman

      Glass is slippery, but if you use small pieces and have a grout line, the surface as a whole has traction.

  25. Thea Avatar

    Great tutorial. I have a stained glass concrete stepping stone where I did the upside down method. It held up for almost a year outside, but recently the concrete at the corner has crumbled away, and two pieces of glass are now loose and I can take them off. Any recommendations on how to fix that? Also how close to the edge can the mosaic before you risk crumbling after being stepped on repeatedly? Thanks

    1. Joe Moorman Avatar
      Joe Moorman

      I understand completely.

      The method of using a paver instead of pouring your own concrete eliminates a lot of those edge problems.

      Concrete needs to be packed tight to eliminate voids, and this hard to do when the same step of pouring concrete is also used to attach the mosaic.

      Starting with a pre-made paver means that you start with a solid backer AND attaching the mosaic to it is a separate step.

      Your existing problems could be fixed with thinset mortar and a palette knife. You could shore up the edges and reattach tiles as needed.

      Use a brush to clean the stepping stone before applying mortar.

      I hope this helps!

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