Log the revision identity before reading the change
Record the project, sheet number, revision number, revision date, and the set in which the sheet was issued. Note whether the sheet replaces an earlier sheet or adds to it. If the team is working from a combined set, confirm that the sheet is the current version and that the addenda list does not supersede it.
Keep the previous sheet beside the revision. Reviewing a change without the prior condition forces the reader to guess what moved. The comparison also protects against a revision that restores an earlier detail, which can reverse a previous quantity adjustment without anyone noticing.
Compare the sheets and list the visible changes
Walk the revision clouds, then walk the rest of the sheet. Reissued sheets often contain unclouded changes to dimensions, notes, or schedules. List each change in plain language: a wall moved, a door type changed, a note added, a detail deleted.
Do not assign a cost yet. Check the general notes and the drawing index as well. A revision that only updates a detail may also change a reference that other sheets depend on.
The goal of this pass is a complete change list, not a price. Pricing too early narrows attention and causes the reviewer to miss the second effect.
Map each change to the affected quantity
For each change, name the takeoff line and the quantity driver. A moved wall changes partition length, finish area, and possibly electrical devices. A revised door schedule changes door count, frame count, hardware sets, and fire rating.
Write the before and after values and the unit for each. Some changes affect an assumption rather than a count. A new note about sequencing may change the temporary protection quantity.
A revised specification may change the waste factor. Record the assumption and its source so the next reviewer can test whether the adjustment is still valid. The addendum scope impact register is the right home for changes that arrive through a formal addendum.
| Revision | Evidence to compare | Review owner |
|---|---|---|
| Sheet identity | Previous and current sheet | Document control |
| Clouded change | Detail, dimension, or note | Trade estimator |
| Unclouded change | Full sheet comparison | Chief estimator |
| Quantity effect | Before and after takeoff values | Quantity reviewer |
| Specification conflict | Governing section and schedule | Design coordination lead |
| Priced delta | Cost code and revision reference | Estimator |
Check for conflicts with specifications and schedules
A drawing revision can conflict with a specification section that was not reissued. Compare the changed detail with the governing specification and with any schedule that references it. If the documents disagree, log the conflict and route it to the design team rather than choosing the more convenient version.
The same check applies to structural, mechanical, and electrical coordination. A revised opening may conflict with a structural member, and a revised equipment location may change a power run. The estimator does not resolve the design, but the estimate should not bury the conflict inside a single price.
Price only the verified delta
Once the quantity and the source are confirmed, price the difference between the prior condition and the revised condition. Do not reprice the entire assembly unless the change actually invalidates the assembly. Keeping the delta small makes the adjustment reviewable and preserves the original basis for the rest of the line.
Carry the price to the correct cost code and note the revision reference beside it. If the delta is uncertain, use a range and state the assumption rather than forcing a single number. The estimate review evidence index should link the revision, the quantity worksheet, and the priced adjustment together.
Freeze the reviewed set and record what remains
After the review, mark the drawing set as reviewed for this estimate version. Record the sheet list, the revision numbers, and the date. This prevents a later reviewer from mixing a newer sheet with an older price without reopening the review.
List any revision that could not be priced because a detail is unresolved. Assign an owner and a needed date. A visible open item is safer than a silent assumption, especially when the bid deadline is close and the design team is still answering questions.
Use the same method for post-bid changes
The same review works after award, when a revision becomes a change order or a construction change directive. The record should show the prior condition, the revised condition, the quantity delta, and the pricing basis. That continuity reduces disputes and makes the change easier to audit.
For steel and other fabricated scopes, confirm the revision against the fabrication and erection documents rather than the architectural sheet alone. The AISC standards and resources library publishes reference material that helps the team frame those coordination questions without pretending to replace the engineer of record.
When the set is too large to compare fully
On a large project, a full sheet by sheet comparison may not fit the bid schedule. Use a risk based sample instead. Always compare the sheets named in the revision, the sheets that reference them, and the sheets that carry the largest quantities.
Then sample the remaining sheets for unclouded changes in dimensions, notes, and schedules. Record the sampling rule so the review can be repeated. A reviewer should know which sheets were compared directly and which were sampled.
If a later question falls outside the sample, reopen the review for that sheet rather than assuming the earlier pass covered it. The record is what makes a partial review honest. A sample is not a shortcut around judgment.
It is a stated limit on what was checked. Write that limit in the estimate record and mention it when the bid basis is discussed.
A reviewer who knows the limit can decide whether more work is needed before release. Record that decision next to the review date so the next estimator knows why the sample was accepted.
