Flowchart of Redline Markup and As Built Drawings Sample Being Implemented In The Construction Projects


Legend: IFC – Issued For Construction

The flowchart of Redline Markup and As Built Drawings shows how the redlines shall be prepared following the approval and implementation of each construction activity. This describes the process, roles and responsibilities, requirements, records to be maintained, and approval of redline drawings. The “red-line” is being kept and updated by the  Construction Team and the  “As Built” submission where the reflected redline markup is being done by the Engineering Team or Technical Team designated by the contractor’s project organization.

A red-line drawing is a form of intermediate drawing that reflects modifications or corrections to a previous drawing. The words “red line” usually refer to the red pen used to mark changes to the drawings by hand. For example, structural drawings were made at the start of a new construction project. The contractor will “red line” the drawings showing the modifications at the end of the project. The record drawings are then created using red-lines. Record drawings, also known as “as-built” drawings, accurately represent what was built and are used for future work or reference.

Detailed steps taken in the  flowchart are as follow:


1. The redline marking process starts and based on the approved activity on-site raised through an inspection (i.e. Inspection Request) to the Consultant.

2. The construction team will take the controlled copy of approved drawings and will stamp it with the “Redline” stamp in the “green” (or whatever color propose to be used in stamping but will stand out different from the approved drawing stamp color).

3. Changes on the site shall be marked with “RED” color on the controlled copies. This is a continuing process that is being implemented and updated during the project duration by the Construction team with thorough knowledge of how the marking is being prepared.

4. Log of Redline Markup Drawings shall be prepared by Construction Department and validated by QC Department. The redline drawings include importantly the items  mentioned on the list as follows but not limited to:

  • All changes of details
  • All changes of dimensions
  • All changes in levels
  • Any additions such as material changes, reference of approved IR (Inspection Request), Site Clarification Request/Request For Information (or similar form based on the Project Documentation), Site Instruction (or similar form based on the Project Documentation), etc.
  • Update to Notes
  • Reference to IFC drawings
  • Utilities – Existing and Diverted 

5. After the above changes are noted by handwritten redlines on the controlled copy of shop drawings, IR (Inspection Request)  for verification with the Consultant shall be raised by Construction Department.


1. Once the IR  was raised (including Contractor’s prepared Redline Drawing), joint inspection between Contractor QC team and Consultant team shall be carried out.

2. After the joint inspection was verified and approved by both parties, Redline Markup Drawings will be submitted.


1. The Redline Markup Drawings including records and evidence of all the changes and adjuncts noted on-site, including joint survey copy and other necessary information shall be prepared.

2. If necessary an advance review workshop shall be carried out on the prepared Redline Markup Drawings with the Consultant. This helps avoid the repeated rejections experienced during the submission process.

3. Once the review was completed and all the advance comments were addressed, the complete Redline Markup Drawing Set shall be officially submitted for approval by the Consultant.


1. After the Redline Markup Drawing Set was approved, Original Electronic files of Redline drawings shall be updated by Engineering Department/ Technical Team.

2. Preparations of As Built Drawings shall be based on the approved Redline Markup Drawings.

3. As part of QA procedures, it is imperative to maintain the log of Redline Markup and As-Built Drawings.

4. It is important to reflect on the As Built Drawings the following items:

  • “AS BUILT” title block is required to be added
  • Original drawing number to be retained
  • Original sheet number to be retained
  • Revision status to be changed to “00”
  • Add “Z” suffix after Drawing number


1. Once the preparation and review were completed by the Engineering Department/Technical Team, the complete As-Built Drawing Set shall be officially submitted for approval by the Consultant.


The priority of the As-built documents is the exhaustive accuracy of the information transferred from the marked-up of the Redline drawings and the timeliness of the completion of the documents. However, to effectively verify the accuracy, real checking needs to be at the markup drawing stage to confirm that the Contractor is on track and complying with the documentation requirements. If the redline markup drawings are considered accurate, then the only effort needed in As-built documents will be to review and confirm that all redline markups have been represented and reflected in the CAD drawings.
The following are the options for when the verification of the Redline markups could be conducted against the actual installation.
1. Completion stage of the project
This is a one-time full verification walkthrough of the project which could be disturbing,    troublesome, and disruptive due to the need to check for example the ceilings, walls, and concealed areas. The possibility to verify the installation of concealed, non-accessible areas would be minimal and sometimes difficult to enter and check.
Moreover, during this period the accuracy of the works done for the particular activity will be hard to document as it will be tiresome to collect and retrieve all the information and records for updating the redline markup drawings.
The redline markup drawings process should be part of the document control procedure wherein documentation is updated regularly.
2. Before the construction elements/system components are covered/concealed
This requires close coordination between the Contractor/Sub-contractor and the Inspectors to make sure the prompt scheduling of verification prior to concealment without delaying the construction progress. As the construction elements are being concealed at various locations and stages, required are various numbers of verification exercises.
3. Regular basis during the progress of the construction
The most effective way of assuring that all system components and information are documented without causing delay to the construction schedule. This exercise can be very time-intensive for all parties as this is being conducted on a regular basis. Sometimes, due to the complexity of the construction activities options, 2 and 3 can be adopted jointly but giving due importance to the latter.

Tips when recording Redline Markup & As-built drawings

Tips when recording redline markup and as-built drawings in construction project


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  1. I think to make redline change concept more traceable, we need to create a Redline Change Request form which include Responsibility i.e (Person Requested by) and authority (Authorized by) and any relevant information needed to start redline drawing. This is a Quality form to go with this Quality process.

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