What is fair-faced concrete?
Fair-faced concrete, also called architectural or exposed concrete (Dutch: schoonbeton or zichtbeton), is concrete for which specific appearance requirements are set in advance for the surface that will remain visible. The concrete is therefore not plastered, tiled or clad. It is usually cast in situ, but precast elements can also be made to a fair-faced finish.
Because the surface is an imprint of the formwork, any carelessness remains visible. Repairs afterwards are almost impossible to hide. A good result requires preparation and precise workmanship.
Types
In the Netherlands, CUR Recommendation 100 (Schoon beton) distinguishes four main types:
- Type I: as struck, smooth (for example cast against smooth form panels).
- Type II: as struck, textured (for example a board-marked finish or a form liner).
- Type III: treated, for example grit-blasted, acid-etched, polished or bush-hammered.
- Type IV: unformed surfaces, such as finished top faces.
Any type can be grey, white or coloured with pigments or special aggregates.
Application
Fair-faced concrete is used for walls, stairs, columns, facades and worktops, and in civil works such as bridges. Tips and common mistakes:
- Method statement and sample panel: agree the desired appearance in advance and cast a sample panel as the benchmark.
- Formwork: use clean, undamaged and well-sealed formwork. Leaking joints cause honeycombing and dark edges. Plan the positions of panel joints and tie holes as part of the design.
- One mix, one supplier: changing raw materials cause colour differences.
- Release agent: apply thinly and evenly; too much causes staining.
- Placing and compaction: pour in layers and vibrate evenly; too little leaves blowholes and honeycombing, too much causes segregation.
- Curing and protection: prevent rapid drying and protect the surface from damage and dirt during later work.
- Cost: expect a clear premium over ordinary concrete, mainly for formwork and labour.
Related Terms
- Concrete
- Formwork
- Honeycombing
- Form liner
- Bush hammering
Discover our DIY plans at fredsdiyplans.com