Coordination drawings on a small job: preparation, review and revisions
The office fit-out has no BIM coordinator. Four trades need to reconcile crowded corridors and a mechanical room, but nobody has agreed who prepares the overlay or how route revisions are issued. A signed sheet is being discussed as if it will settle every later cost dispute.
Assign a drawing lead for the defined areas, agree the information each trade provides and identify the required technical and commercial review. State what an acknowledgement records and how revisions are authorized and communicated. A signature alone does not determine every route-change cost or approve an engineering solution. The coordination drawing needs a current document reference and a clear status, with unresolved questions visible rather than hidden under four names.
Give the overlay a clear document owner and status
- Choose the areas and preparation lead. Identify locations where an overlay is useful and appoint a capable lead with the agreed resources. Do not assume the largest-duct trade always owns the task. Check actual package responsibilities and who supplies dimensions, clearances and other necessary information.
- Agree the routing review process. Have relevant trades and qualified professionals identify constraints and resolve conflicts on the applicable basis. A proposed order can organize discussion, but there is no universal priority list that replaces design requirements, access or maintenance needs.
- Define each acknowledgement. State which information was provided or checked, the drawing revision and remaining qualifications. Have authorized people confirm any contractual meaning. A trade's signature should not silently become acceptance of another discipline's design or automatic liability for every later change.
- Control subsequent revisions. Give each revised issue a reference, change description and required review status. Route cost, time or authority questions separately where needed. Preserve earlier issues and withdraw superseded field copies through the actual document process.
- Communicate the current instruction. Confirm the relevant crew has the approved information and unresolved items remain identified. Review clashes against the current history rather than declaring whoever moved last must pay. The commercial lead and qualified reviewers assess the actual instruction, cause and responsibilities.
Common mistakes
- Appointing a lead without checking scope and resources.
- Using an assumed right-of-way hierarchy as design authority.
- Treating a signature as automatic allocation of later costs.
Checklist
The coordination drawing's control record
- Defined areas and preparation lead.
- Current trade inputs and qualified review.
- Project-specific routing decisions.
- Acknowledgement meaning and qualifications.
- Revision history and approval status.
- Current crew information and separate cost review.
Check your understanding
All four trades signed the overlay, and a later route clashes. Can you assign the cost solely from the signatures?
