In a college project, I was instructed to design the floor plans and the conduit layout of a duplex building. It was instructed that the duplex is 2500 square feet. No other instruction was provided. Now while drawing, should I draw 2500 square feet for each of the floors (that is 5000 sq ft altogether) or 1250 sq ft for each (2500 altogether)?


It’s total square footage not per floor square footage.

Btw, the AIA has established EXACTLY how to calculate square footage of a building. That is to say, overhangs, canopies, balconies, pipe chases, open terrace, etc. is considered 1/2 square footage. So, if there is a 200 square foot entry canopy, it’s considered 100 square feet in the calculations. (You can see this graphically drawn in AIA Document D101...you can Google it. This document is part of the Architect’s contract.)

So, your 5,000 sf building is not necessarily 2500 sf per duplex nor 1250 sf per floor in each duplex. You’ll need to subtract canopies, overhangs, etc. and then divide the balance of the square footage up with each duplex and each floor.

  • 1
    $\begingroup$ I should add that in the UK at least it's also excluding area taken in by the thickness of dividing walls - the floor area is what counts. $\endgroup$ Dec 12 '20 at 11:13
  • $\begingroup$ In the U.S. the wall thickness does count. $\endgroup$
    – Lee Sam
    Dec 12 '20 at 13:19

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