I'm building a custom shower wall and want to put LED lights behind some of the clear/glass tiles but obviously thinset isn't clear so it'll cover the light or at a minimum part of it. Only like 1/10th of the tiles will be lit and the rest will be various colors, also small hexagon tiles.

Anything I can use other than normal thinset? Also this will be in a custom RV so need good strong adhesive.

  • 1
    Small light tiles I might try clear silicon or a similar adhesive, but the cost will probably be much higher. Heavy tiles might be iffy.
    – crip659
    Commented Sep 27, 2023 at 15:06
  • You say "clear/glass tiles" - these are 3-5mm thick (1/4" or less) tiles, not glass block, right? If so, I'd agree that clear silicon would probably be your best bet. You may want to make up a sample to ensure that you're still getting the expected amount of light through, then clamp the sample in your RV or other vehicle and drive around for a couple of months to ensure that it'll hold up.
    – FreeMan
    Commented Sep 27, 2023 at 15:37
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    If using normal hardware-store silicone, would need to test a large enough area to be sure that you're getting a cure away from the grout lines - that might take months, as it depends on exposure to air and moisture to cure. Other kinds of silicone cure in other ways, but they are a bit more trouble to source, and might be too runny before curing, unless the panel could be laid flat.
    – Ecnerwal
    Commented Sep 27, 2023 at 15:46
  • How big are the lights? Are they tiny LEDs or LED bulb like size(fit in a light socket)? I think they do come in wafer size, which might make asking this question not needed, thinset, wafer lights, tiles.
    – crip659
    Commented Sep 27, 2023 at 18:04
  • Depends on the substrate, but in an RV, it should be mastic anyway? "Thin set is a motar designed specifically for floor installation it's gritty doesn't stay on the wall well when applied. Now that isn't to say it won't work it will, provided you use a cement based backer board such as durarock or hardi-backer. But here is a key walls tend to move and swell more than floors do and thin-set being concrete and gritty isn't great at holding up to the stress. Even the modified/fortified variations have limits. Mastic is designed for walls has outstanding bond and durability."
    – Mazura
    Commented Sep 28, 2023 at 0:25

2 Answers 2


When you go to apply the thinset, you'll be using a trowel with a notch depth appropriate for your tile size. It will, most likely, be somewhere between 1/4" and 1/2" (though a 1/2" notch is mostly for big tiles, most commonly used on floors, so not likely to be used on your RV wall).

Get an aluminum or plastic* U-channel of the proper depth to match your notch depth and just wide enough to put the LED strips in. Apply the channel to your walls where you want the LEDs to run (glue, screws, whatever makes you happy), install the LED strips, then apply your mortar up to the edge of the channel, but not within the channel.

Unless you're using very tiny tiles, they should more than span the width of the channel, meaning the tiles will have adhesive on either side of them so they'll be held in place. With the motion of a vehicle moving down the road and bouncing across dirt roads in an RV park, there's a chance of the tiles falling off due to sub-optimal adhesion. You might consider changing the pattern/tile choice to something that will work better spanning the non-glued space of the channel.

*Use a material/color that will blend the best with your tile choice to minimize visibility of the channel itself. Aluminum might be most visible through translucent tiles because the AL channel will be thicker, while plastic would probably be least visible because it could be very thin walled (there's no structural need for a thick piece of plastic here).


There exist clear grouts for tile. You might consider using that (expensive) stuff and illuminating things from the edges. I remember Sal DiBlasi made a video implementing the concept. There it is: https://www.youtube.com/watch?v=tn0R3Zius98.

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