12.10 - Surface flatness
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Surface flatness is the measurement of surface regularity over short distances to a defined plane when placed directly in contact with the slab (i.e. a 2m straightedge as documented in BS8204-2). This should not be confused with surface level relative to a fixed datum point, refer to Fig 12.9c.
Surface regularity should be measured in accordance with methodology outlined in BS 8204-2 and SCI P300 using a 2m long straightedge placed in direct contact with the concrete surface under its own weight. Deviations of the floor surface are then measured from the underside of the straightedge, between two points of contact with the floor surface, by means of a slip gauge / graduated wedge.
'https://smdltd.co.uk/wp-content/uploads/2016/06/SMD.DAT_.219.V5-DATA-14-Concrete-Slab-Surface-Flatness.pdf Refer to SMD Data sheet 14 - Concrete Slab Surface Flatness]
Where SMD are contracted to carry out the concrete works, surface flatness survey measurements will be taken at predetermined grid spacing’s to suit the slab area and steel configurations for the contract. In areas receiving a skip/easy float surface finish, the positioning of the straightedge will be adjusted, if necessary, to avoid being situated over any localised ridging caused by this method of finishing. The greatest deviation measured is then recorded in a table format to correspond with a drawing identifying the straightedge locations and positions. On completion of works, a formal copy of the surface regularity survey will be issued in accordance with the above as evidence of compliance.
Refer to BS 8204-2:2003 + A2:2011: Screeds, bases and in situ floorings. Concrete wearing surfaces. Code of practice for more information
Other items within 12.0 - Concrete:-
- 12.1 - Site considerations
- 12.2 - Temporary propping
- 12.3 - Cleaning the decking
- 12.4 - Damaged decking
- 12.5 - Construction joints
- 12.6 - Reinforcement drawings and bending schedules
- 12.7 - Concrete mix requirements
- 12.8 - Placement
- 12.9 - Surface finish
- 12.10 - Surface flatness
- 12.11 - Curing
- 12.12 - Post-installation characteristics
