Designing Buildings - User contributions [en]

Floor level (FL)

2023-08-11T14:49:00Z

Matt G:

= Floor Level =

Floor level is a general, informal term to describe the Finished Floor Level (FFL) of a building, but as it is an informal term it may refer to a bare unfinished floor level also.

= Finished Floor Level (FFL) =

[https://www.designingbuildings.co.uk/wiki/Finished_floor_level_(FFL) Finished floor level (FFL)] refers to the uppermost surface of a [https://www.designingbuildings.co.uk/wiki/Floor floor] once [https://www.designingbuildings.co.uk/wiki/Construction construction] has been [https://www.designingbuildings.co.uk/wiki/Completed completed] but before any [https://www.designingbuildings.co.uk/wiki/Finishes finishes] have been applied. So, in [https://www.designingbuildings.co.uk/wiki/Concrete concrete] [https://www.designingbuildings.co.uk/wiki/Construction construction] it may be the uppermost surface of a screeded [https://www.designingbuildings.co.uk/wiki/Finishes finish], or in [https://www.designingbuildings.co.uk/wiki/Timber timber] [https://www.designingbuildings.co.uk/wiki/Construction construction], FFL will denote the top [https://www.designingbuildings.co.uk/wiki/Level level] of floorboards, [https://www.designingbuildings.co.uk/wiki/Chipboard chipboard] or ply [https://www.designingbuildings.co.uk/wiki/Decking decking].

Finished floor level does not take into [https://www.designingbuildings.co.uk/wiki/Accounts account] any applied [https://www.designingbuildings.co.uk/wiki/Finishes finishes] as these may be added by [https://www.designingbuildings.co.uk/wiki/Owner owners], [https://www.designingbuildings.co.uk/wiki/Occupier occupiers] or [https://www.designingbuildings.co.uk/wiki/Tenant tenants], will vary in thickness, e.g a thick shag-[https://www.designingbuildings.co.uk/wiki/Piles pile] [https://www.designingbuildings.co.uk/wiki/Carpet carpet] has different thickness to a laminated [https://www.designingbuildings.co.uk/wiki/Floor floor], and may be replaced.

= Structural Floor Level (SFL) / Structural Slab Level (SSL) =

Structural Floor Level (SFL) or sometimes Structural Slab Level (SSL) in the case of concrete frame buildings, describes the floor level prior to the addition of finishing items such as screed, underlay and flooring. The numerical measure will normally be written next to the abbreviation on a drawing often with a + to indicate vertical increase or - in the case of basements. The figure will be a certain amount above or below whatever the agreed setting out position or datum is. For example the setting out position might be 0.00, the SSL +3.0 and the FFL +3.3.

= Building Ground Level (BGL) =

Building Ground Level (BGL) might be used to describe the setting out position for the building ie the 0.00 from which all other levels will be measured. The height of this in relationship to the site itself will depend on the approach taken and agreed by the project team, though it will normally be slightly higher than the Ordinace Survey (OS) Level or Natural Ground Level (NGL) to allow for structural foundations.

= Ordinance Survey (OS) level =

Ordinance Survey (OS) level, is based on the accepted levels or measures of the lay of land across the United Kingdom, these are calculated through the use of Ordnance Survey Bench marks (BMs) which are survey marks that are made by Ordnance Survey to record the height of the landscape above Ordnance Datum. Based on these and the process of surveying, the more localised OS or what might be call Natural Ground Levels are calculated and recorded.

= Natural Ground Level ( NGL) =

Natural Ground Level ( NGL) is the accepted datum for a site prior to any excavation works to lay the foundations of the building.

= Related articles on Designing Buildings =

* Building survey.
* Condition survey.
* Datum,
* How to layout a building.
* Land surveying.
* Laser scanning.
* Level.
* Levelling applications.
* Mass haul movement.
* Measurement of existing buildings.
* Road construction.
* Robotic total station.
* Site plan.
* Site surveys.
* Surveying instruments.
* Surveyor.
* Verticality.

[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Standard]] [[Category:Definitions]] [[Category:Standards_/_measurements]] [[Category:Construction_management]]

Floor level (FL)

2023-08-10T15:18:04Z

Matt G:

Floor level (FL)

2023-08-01T11:26:10Z

Matt G: