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A plan correction, or redline, is the technical process of identifying and documenting discrepancies between original design intent and actual on-site conditions. These revisions provide a precise record of as-built status, resolving missing details or conflicting information within the construction documents.
The plan correction consists of standardized annotations and markups identifying necessary changes to the construction drawings. It documents the physical differences between the initial design and the final on-site assembly. The documentation provides a revised layout and an accurate record of the structural elements as constructed, incorporating fixed errors and omissions into the final plan set. In a plan correction:
Revision Clouds & Deltas: Clearly outline the corrected areas with cloud-shaped lines (revision clouds) and assign them a revision number or symbol (e.g., a delta symbol ).
"As-Built" Notation: Clearly label the drawing as "Revised Plan," "As-Built," or similar, and update the title block with the date of the revision.
Clearance and Dimensioning: Use continuous, running dimensions for accuracy. Dimensions should be added for any changed walls, doors, or windows, measuring to the face of finishes or structural elements.
Notes and Callouts: Include specific, detailed notes regarding why the change occurred (e.g., "Field condition - pipe obstruction," "Revised per owner request").
Corrected Wall Locations: Accurate dimensions for moved, added, or removed walls, including thickness.
Structural Adjustments: Any changes to beams, columns, or joists.
MEP Revisions (Mechanical, Electrical, Plumbing): Updated locations for plumbing fixtures, electrical outlets, HVAC registers, and ductwork that were moved from the original design.
Window and Door Relocations: New dimensions for the location and size of doors and windows, often measuring to the centerline.
Finished Floor Levels (F.F.L.): Updated elevations if the floor height changed.
Compare to Original: Ensure the original design lines are partially visible or referenced to show the extent of the correction (often shown in a muted or dashed line).
Consistency: Maintain the same scale, drafting style, and title block as the original set.
Redline/Markup Transfer: If this is a revision of a previously marked-up drawing, all previous "redline" notes should be incorporated, and new changes added.
Photographic Evidence: Consider including photos as an attachment to provide context for the correction.
Outdated Information: Remove or strike through all invalidated, old dimensions and notes that no longer reflect the current state.
Redlines (General Corrections): Notes made to suggest changes to plans, elevations, sections, or layouts.
Code Compliance Issues: Changes needed to meet local building codes, such as egress safety, fire resistance, or accessibility.
Conflicts & Coordination: Fixing discrepancies between drawings, such as a duct passing through a beam, or missing dimensions.
Site Conditions: Adjustments made during construction to adapt to unforeseen conditions (e.g., soil issues or existing utilities).
Design Enhancements: Modifications to improve functionality or aesthetics, often based on client feedback.
Identification: Redlines are added to the drawings to indicate areas needing correction.
Modification: Design professionals update the drawings, which often requires "bubbling" (using revision clouds) the changes, dating them, and initialing them.
Documentation: A summary sheet is often prepared, listing every correction made, what was changed, and which sheets were affected.
Certification: In many jurisdictions, a formal document (e.g., Form 420 in Chicago) is required to certify that the corrections meet code compliance.
Redlines: The initial markings, usually in red ink, that highlight errors, omissions, or necessary changes.
Revision Cloud: A cloud-shaped line used to highlight areas of the drawing that have been revised.
Addenda/Revisions: The updated drawing sets that follow the initial submission, often labeled sequentially (e.g., "Addendum 1").
VIF (Verify in Field): A common notation when, instead of correcting the drawing, the architect delegates the final decision to the contractor based on on-site conditions.
Failing to properly manage plan corrections can lead to on-site errors, increased construction costs, and failed inspections. Regular audits and maintaining an updated, consistent set of drawings are critical for accuracy.
