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Estimating process

Drawing register and revision control.

A drawing register records every drawing issued for a project, its revision letter, date, and purpose. Without proper revision control, the estimator may price from obsolete information.

Who this guide is for

Estimators managing multiple drawing revisions, quantity surveyors checking tender information, and contractors who receive drawing updates during the tender period.

How the register works

Each drawing has a unique number, title, scale, revision letter, date issued, and purpose (tender, construction, as-built). When a revision is issued, the old drawing is superseded and the new one added. The estimator must check which revision was used for each quantity and update the estimate when revisions change quantities.

Miniature example

The estimator prices from Rev A of the floor plan showing 12 windows. A Rev B is issued changing two windows to French doors. The register shows Rev B supersedes Rev A. The estimator updates the quantity and re-prices the affected items before submission.

Common mistakes

• Pricing from a personal copy that is not the latest issue
• Not tracking what quantities came from which revision — impossible to audit later
• Ignoring transmittal notes that describe what changed between revisions