An exposed aggregate floor is a concrete floor or slab where the top skin of cement is washed off shortly after casting, so the top of the gravel or decorative aggregate becomes visible and can be felt. The result is a decorative, rough and slip-resistant surface. Terrazzo is a related technique in which the surface is instead ground to a smooth finish.
Exposed aggregate versus terrazzo
| Feature | Exposed aggregate | Terrazzo |
|---|---|---|
| Finish | Rough, grains stand proud | Ground smooth |
| Technique | Wash off cement skin | Grind and polish |
| Grip | Slip-resistant | Smooth |
| Use | Outdoors, terraces | Indoors, floors |
How is it made?
To expose the aggregate, the cement skin, which has not yet fully set, is washed off with water and a brush shortly after casting. Sometimes a retarder is applied to the formwork or the surface to slow the setting of the top layer. For terrazzo, the concrete is first left to harden fully and the surface is then ground and polished by machine.
Application
- Terraces and garden paths — decorative and slip-resistant
- Decorative paving — slabs and edgings with visible gravel
- Facade panels — exposed aggregate concrete as a decorative finish
- Indoor floors — terrazzo as a durable, attractive finish floor
Related Terms
- Gravel floor
- Gravel concrete
- Decorative concrete
- Screed
- Gravel
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