As-Built DrawingsIntroduction
In the lifecycle of a building, documentation is rarely static. From capturing the reality of a 100-year-old historic structure before a renovation, to formally recording the field changes made by a contractor during construction, As-Built Drawings are critical.
Whether you are an architect starting a tenant improvement project or a facility manager updating a campus map, having accurate existing conditions data is non-negotiable. In this FAQ guide, our senior VDC consultants answer the most pressing questions regarding As-Built drawings, redlines, and the modern Scan-to-BIM workflow.
Key Takeaways
Key Takeaways
General As-Built Questions
1. What are As-Built Drawings?
As-Built drawings (sometimes called Existing Condition drawings) are CAD or Revit files that document the exact physical layout and dimensions of an existing building, including any deviations from the original design blueprints.
2. Why are As-Built drawings necessary?
If an architect designs a renovation based on outdated blueprints, the new custom casework or structural steel will not fit. As-Builts provide the accurate baseline required to design a constructible project.
3. What is the difference between As-Builts and Record Drawings?
- As-Builts: Typically created by the General Contractor during construction. They take the architectural plans and use a red pen to mark exactly where they moved a wall or a pipe in the field.
- Record Drawings: The final, clean CAD/Revit files created by the Architect at the end of the project, incorporating all the contractor’s redlines into an official historical document.
4. Who needs As-Built drawings?
Architects (for renovation baselines), General Contractors (to close out a project), Facility Managers (for maintenance and space planning), and Real Estate Developers (to calculate accurate leasable square footage).
5. Can I just use the original building blueprints?
No. During the original construction, contractors inevitably made field changes that were never recorded. Relying on original blueprints for a modern renovation is the number one cause of costly field clashes.
Field Capture and Scan-to-BIM
6. How are existing conditions measured?
Traditionally, junior staff used a tape measure and a laser disto. Today, the industry standard is 3D Laser Scanning (LiDAR), which captures the environment with millimeter precision.
7. What is Scan-to-BIM?
Scan-to-BIM is the process of using a 3D laser scanner to capture a building (creating a Point Cloud) and then importing that data into Revit to build a highly accurate 3D As-Built model.
8. What is a Point Cloud?
A Point Cloud is a massive digital file containing millions of colored data points in 3D space, generated by a laser scanner. It looks like a ghostly 3D photograph of the building.
9. Can I give you a Point Cloud and have you make the CAD drawings?
Yes. Core BIM Solutions specializes in this exact service. You send us the raw Point Cloud (.RCP or .RCS file), and our drafters trace it to create perfect 2D CAD floor plans or 3D Revit models.
10. How accurate is a laser scan compared to hand measuring?
A commercial terrestrial laser scanner is accurate to within 1-3 millimeters. Hand measuring is prone to human error and is typically only accurate to within 1-3 inches.
Redline Revisions and Drafting
11. What is a “Redline”?
A redline is a markup on a drawing indicating a change or correction. It is named for the red ink traditionally used to ensure the markup stands out against the black-and-white architectural plans.
12. How does the Redline process work?
The General Contractor marks up the physical paper plans on the job site (or uses an iPad with Bluebeam) whenever they deviate from the design. At the end of the project, they hand these redlined PDFs to the architect. The architect’s CAD team updates the original files to match the redlines.
13. Can I outsource my redline pickups?
Yes. Processing redlines is tedious, non-creative work. Outsourcing this to a specialized CAD drafting firm is highly cost-effective and frees up your internal staff for new design work.
14. What format should I send my redlines in?
Scanned PDFs of hand markups are acceptable, but the most efficient method is a digitally marked-up PDF using Bluebeam Revu, Adobe Acrobat, or PlanGrid.
15. Do As-Built drawings show MEP systems?
They can, if requested. A standard architectural As-Built shows walls, doors, and windows. However, a laser scanner captures everything visible, allowing us to model exposed HVAC ductwork, plumbing, and structural beams if you require a higher Level of Development (LOD).
Pricing and Delivery
16. How much do As-Built drawings cost?
Pricing depends on the square footage of the building and the required detail. Drafting a simple 2D CAD floor plan from field notes is relatively inexpensive. Building a massive, LOD 300 Revit model from a point cloud requires more hours.
17. How long does it take to draft an As-Built set?
For a standard commercial interior (10,000 sq ft), turning a point cloud or field sketches into a clean set of 2D CAD floor plans and reflected ceiling plans typically takes 1 to 2 weeks.
18. What deliverables do I receive?
Depending on your request, we deliver the native DWG (AutoCAD) files, RVT (Revit) models, and a clean set of plotted PDFs ready for printing.
19. Do you use my firm’s CAD standards?
Yes. We require your standard CAD template (.dwt) or Revit template (.rte) so the final As-Built drawings perfectly match your firm’s line weights, fonts, and title blocks.
20. Why should I use Core BIM Solutions for my As-Builts?
We combine extreme drafting precision with scalable capacity. Whether you need a team to process a massive backlog of contractor redlines or convert a 100GB point cloud into a pristine Revit model, we provide the expertise to get it done quickly and accurately.
Conclusion
Accurate As-Built drawings are the bedrock of any successful renovation or facility management strategy. By moving away from inaccurate hand-measurements and embracing Scan-to-BIM technology—and by strategically outsourcing the heavy drafting required to process point clouds and redlines—firms can drastically reduce field errors and protect their profit margins.
Call to Action
Do you have a stack of contractor redlines or a massive Point Cloud that needs to be modeled? Contact Core BIM Solutions today to request a quote for our fast, accurate As-Built drafting and Scan-to-BIM services.
