Drawing identifications – numbers, letters, revisions etc. – are (in my opinion) put there to:

  • Help find what you need easily,
  • Keep documents in order, and,
  • Reduce the chance or instances of errors… and some errors can be costly in the building industry.

So why then is it that sometimes documents (most especially tender set drawings) are issued with non-consecutive numbers? For example, drawings numbered like this:

  • A100, A101, A102, A103
  • A201, A202, A203, A204, A205
  • A301, A302
  • A401
  • A500


This can be a real hassle for estimators and subcontractors.

If a number is ‘missing’; … Is it meant to be missing? Have I lost a drawing? What’s going on? And I hope I don’t make a mistake. Who’s to know? (These are most likely the thoughts of a frustrated and under-pressure estimator and subcontractor.)

Yes, I know maybe it’s good for consultants in their office to have regular drawing number & naming systems from job-to-job, and I’m sure it works well … for you.

But the drawings aren’t just for your benefit … they’re for the benefit of the builder, subcontractors, suppliers and the client.

And don’t forget, builders and subcontractors get drawings from many sources in many formats … Systems that are convenient for you in your office, may be new and inconsistent to them and won’t always help them on a busy building site or in their office.

For example:

  • On a small renovation, the electrical engineer issued for tender drawings:
  • E01, E02, E03, E04 and E10 – What happened to E05 to E09?

 Revision numbers (or letters) on re-issued or amended drawings are also very important … they need to be clear and obvious.

Tip : Do not remove these revision numbers (or letters) at the time of tender, or when issuing the contract documents … this is a dangerous practice.