How to Make Translucent Concrete

Ruth de Jauregui

Concrete is traditionally a solid building material. Recent innovations, however, have brought translucent concrete to the forefront in new construction. By incorporating fiber optic threads into the concrete blocks, light is transmitted through the wall.

The light at the end of an optic fiber is carried through the fiber from the opposite end.

The unique properties of fiber optics allow you to see shadows and colors from one end of the fiber to the other, despite the solid mass of the concrete. This project will focus on building translucent concrete bricks for a wall in the home or garden.


Recycle fiber optic threads from toys such as fiber optic wands. Use clay to make custom molds for your special projects.


Wear gloves, safety glasses and a dust mask when working with concrete mix. The silicates in the cement are irritants to your skin, eyes and lungs.

  1. Cut fiber optic threads to the width of the brick mold, approximately 4 inches. In the United States, the standard brick size is 8 by 4 by 2 inches.

  2. Pour a little vegetable oil into a brick mold. Wipe with a rag so only a thin film of oil covers the inside of the mold.

  3. Pour 2 cups of concrete mix into a bucket. Add water to the mix and stir until the mix is the consistency of pancake batter.

  4. Spread one half cup of the mixture in the bottom of the mold.

  5. Spread fiber optic threads in a thin layer across the width of the brick. The fibers must touch each side of the mold in order for light to reach through the finished brick.

  6. Add another half cup of concrete mixture, gently spreading it over the fibers. Continue layering the optic fibers and concrete mixture, making sure the threads extend across the width of the mold and ending with a layer of concrete.

  7. Tap the mold to settle the concrete and break up any interior bubbles. Cover with plastic wrap and allow to dry for 24 hours.

  8. Turn the mold upside down and tap to remove the brick. Allow the brick to finish air drying.

  9. Turn off the lights and hold a flashlight up to the brick. The light is transmitted through the brick by the fiber optic threads embedded within the concrete.