Surface finish quality
There are three main factors required to produce a good quality concrete surface:
1. The correct quality of concrete, which has been designed to achieve its ‘finishability’.
2. The use of the correct type and quality of form face material and release agent suitable for the finish specified.
3. Workmanship (also referred to as execution), both in producing the formwork and mixing, placing, compacting and finishing the concrete.
The Concrete Society Advice 17 Achieving good quality as-struck in-situ concrete surface finishes gives some guidance on achieving good quality finishes.
Note: Terminology is important, CP110 1970 , the forerunner to current structural concrete codes, stated in clause 6.10.1 that The appropriate finish, which may vary from face to face, should be carefully chosen and clearly specified. The use of terms such as ‘fair-faced’, ‘blemish free’ should be avoided.