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521 MINIMUM PERIOD FOR RETAINING FORMWORK/ TEMPORARY SUPPORTS IN POSITION
• Concrete strength at time of formwork removal (minimum):
As BS 8110, clause 6.2.6.3.
• Assumptions: Maturity of adjacent elements of structure is at least equal to element
under consideration.
- Before removing formwork: Submit proposals if assumptions will not be realised.
• Method to be used in assessing early age strength of concrete: Submit proposals
and Temperature matched curing (TMC) of cube samples to BS 1881-130.

FORMED FINISHES

605 CONTROL SAMPLES
• Sample areas that are part of the finished work: Location: Obtain instructions.
• Approval of appearance: Obtain before proceeding with remainder of the work.

610 BASIC FINISH
• Requirements: Face fully compacted and to tolerance, otherwise no particular
requirements.
• Use: Faces below ground level.

620 PLAIN SMOOTH FINISH
• Finish: Even with panels arranged in a regular pattern as a feature of the surface.
• Permissible deviation of surfaces:
- Sudden irregularities (maximum): 5 mm.
- Gradual irregularities when measured from the underside of a 1 m straightedge,
placed anywhere on surface (maximum): 5 mm.
• Variations in colour:
- Permitted: Those caused by impermeable form linings.
- Not permitted: Discoloration caused by contamination or grout leakage.
• Surface blemishes:
- Permitted: Blowholes less than 10 mm in diameter and at an agreed frequency.
- Not permitted: Voids, honeycombing, segregation and other large defects.
• Formwork tie holes: In a regular pattern and filled with matching mortar.

630 FINE SMOOTH FINISH
• Finish: Smooth and even. Panels to be as large as is practicable and arranged in a
regular pattern as a feature of the surface.
• Permissible deviation of surfaces:
- Sudden irregularities (maximum): 3 mm.
- Gradual irregularities when measured from the underside of a 1 m straightedge,
placed anywhere on surface (maximum): 3 mm.
• Variations in colour:
- Permitted: Those caused by impermeable form linings.
- Not permitted: Discoloration caused by:
Contamination or grout leakage.
Replacement of formwork panels.
• Cover spacers: Submit proposals.
• Surface blemishes:
- Permitted: Blowholes less than 5 mm in diameter and at an agreed frequency.
- Not permitted: Voids, honeycombing, segregation and other defects.
• Formwork tie holes: Prohibited.

RotF generic (intermediate) NBS 2014 6118-AEW-XX-XX-NBS-A-01