OldieNewbie Posted January 28 Posted January 28 Hello all, You know on the drawings that get given to the contractor for construction, well on those drawings theres “icons” that might indicate FFL +2.72 & Eaves Level 7.90. I take it that means that’s the height that the builder has to work to is it? But where is this measurement taken from? Like where do you measure up 2.72 from? The foundation?
OldieNewbie Posted January 28 Author Posted January 28 32 minutes ago, Canski said: Usually from finished floor level ( FFL) Thanks for the response. The drawing I seen included a measurement to floor level finish so it wouldn’t be that. From my novice research since posting question, would it be the measurements off a pre determined datum that an engineer provides??
Benpointer Posted January 28 Posted January 28 Our draft drawingsa specify the FFL in metres above see level (100.35 in our case). That is taken from our topographical survey. (We're currently debating with the architect whether we should raise the FFL up by 0.2m, given the amount of rain we've had this winter.) 1
Conor Posted January 29 Posted January 29 9 hours ago, OldieNewbie said: Thanks for the response. The drawing I seen included a measurement to floor level finish so it wouldn’t be that. From my novice research since posting question, would it be the measurements off a pre determined datum that an engineer provides?? Usually there will be a benchmark / datum set on site, and everything will be referenced off that. The datum then usually has mao coordinates associated with it, so all subsequent dimensions can be calculated to the map grid, e.g. ridge height which would need to be known for planning purposes 1
DevilDamo Posted January 29 Posted January 29 It will not be foundation level as those depths can vary. Can you upload an extract of the drawing? 1
Mr Punter Posted January 29 Posted January 29 10 hours ago, Benpointer said: We're currently debating with the architect whether we should raise the FFL up by 0.2m, given the amount of rain we've had this winter. If you are able to do this without severe planning implications then I would 100% recommend you do. 1
OldieNewbie Posted January 29 Author Posted January 29 11 hours ago, Conor said: Usually there will be a benchmark / datum set on site, and everything will be referenced off that. The datum then usually has mao coordinates associated with it, so all subsequent dimensions can be calculated to the map grid, e.g. ridge height which would need to be known for planning purposes Thanks for the response. Who would set / specify the datum? Excuse my ignorance, but what are MAO co-ordinates? Or is that a typo for Map? 😂
OldieNewbie Posted January 29 Author Posted January 29 11 hours ago, DevilDamo said: It will not be foundation level as those depths can vary. Can you upload an extract of the drawing? I’ll try to a picture of one on the Google and post it.
OldieNewbie Posted January 29 Author Posted January 29 47 minutes ago, Canski said: Did you have a Topo survey. No. This is only a question from a curious construction fan. It is not a project specific query.
DevilDamo Posted January 31 Posted January 31 On 29/01/2025 at 20:19, OldieNewbie said: I’ll try to a picture of one on the Google and post it. Any luck?
OldieNewbie Posted February 1 Author Posted February 1 12 hours ago, DevilDamo said: Any luck? After much searching via several search engines I came across this.
Canski Posted February 1 Posted February 1 4 hours ago, OldieNewbie said: After much searching via several search engines I came across this. Just as I explained previously.
OldieNewbie Posted February 1 Author Posted February 1 7 hours ago, Canski said: Just as I explained previously. Is a finished floor not in after all of the heights detailed in drawing are set out? do you not have a sub floor in first, and then your finished floor. If so, how could you be taking sizes from something that isn’t there?
Canski Posted February 1 Posted February 1 56 minutes ago, OldieNewbie said: Is a finished floor not in after all of the heights detailed in drawing are set out? do you not have a sub floor in first, and then your finished floor. If so, how could you be taking sizes from something that isn’t there? It may not be there but it is known where it will be. It is quite normal for heights to be worked out from FFL either upwards or downwards. 1
OldieNewbie Posted March 2 Author Posted March 2 Similar question with this one guys, What does GFL mean? Am I correct in saying ground floor level? Is ground floor level the garden or patio level where FFL is inside the building? What does the +37.82 mean? Does it mean the area highlighted in the drawing attached is the measurement down to the ground outside? Is the area in the drawing nearly 38mm above the external ground?
Alan Ambrose Posted March 2 Posted March 2 Usually absolute height above sea level in metres. The '+' is a bit leading - it means above sea level not whatever your GFL is +37.82m - unless you have a 10 storey building, in which case GFL+38 might make sense. If you think about it, only the absolute value completely specifies your exact level. 1
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