Prepare comparable sheets
Confirm that both sheets cover the same area, scale, orientation, and drawing number. Align known grid intersections or dimensions before trusting the overlay. A shifted crop can create hundreds of false differences that hide the real revision.
Record the old and new issue dates and include the addendum or bulletin that transmitted the change. Use the document issue register as a related estimate control.
Classify every meaningful change
Separate added, deleted, relocated, and clarified work. Check notes, schedules, details, and specifications even when plan geometry appears unchanged. The estimate document issue register identifies which files belong in the comparison.
The Bluebeam overlay guidance explains software functions for comparing document revisions. The estimator must still interpret each change against the contract documents.
| Review field | Required record |
|---|---|
| Sheet | Old and new revisions |
| Change | Added, deleted, relocated |
| Quantity | Prior and revised amount |
| Cost action | Code, quote, or clarification |
Update quantity and cost together
Revise the takeoff, trace the affected estimate codes, and identify quotes requiring refresh. Preserve the prior quantity so reviewers can understand the delta.
If a change is visible but not measurable, state the temporary estimate treatment. Reconcile the result through the addendum impact estimate review before the revised estimate is approved.
