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As-built, also referred to as as-built documentation or an as-built model, describes the documented actual condition of a building. An as-built model shows how a building was actually constructed – including deviations from the original design, on-site changes and final dimensions.
Why is as-built documentation important?
- Reliable building data: As-built documentation provides a precise and legally relevant basis for handover, operation, refurbishment, renovation, warranty claims and billing.
- Reduced costs and risks: Accurate as-built data helps avoid planning errors in follow-up projects, reduces change orders and minimizes additional site visits.
- Efficient refurbishment: Precise existing building data accelerates energy assessments, MEP adjustments and funding applications.
- Digital workflows: Structured as-built data, for example in BIM or IFC formats, can be searched, versioned and linked with operational or sensor data.
How does as-built documentation work in practice?
- Data capture: A digital building survey records the existing condition using terrestrial laser scanning, mobile mapping with SLAM/LiDAR or photogrammetry. The result is usually a combination of point clouds and images.
- Model or plan creation: Scan-to-BIM converts point clouds into a semantic as-built model, including elements such as walls, openings and MEP objects. Alternatively, 2D floor plans, sections and elevations can be derived.
- Handover: As-built data is typically exported as IFC, DWG or DXF. Additional metadata such as date, version and tolerances should also be included. During operation, the data can be used in CAFM or BIM environments.
As‑Built vs. As‑Planned
- As-planned: The intended design status before construction. It serves as the basis for execution.
- As-built: The actual condition after construction. It is relevant for building operation, refurbishment, renovation and billing.
FAQ
What is the difference between as-built and existing building plans?
Existing building plans are often 2D drawings derived from a 3D model. An as-built model is usually a semantic 3D model with attributes and can represent changes in more detail.
Which formats should be used for as-built data?
For BIM workflows, IFC is usually used for models, while DWG or DXF are common for 2D plans. PDF can be added for readable and legally relevant documentation.
How can I ensure the quality of an as-built model?
Quality can be ensured through defined tolerances, documented measurement methods, quality reports such as RMS values or checkpoints, and version control with a change log.