Why Are As-Built Drawings Important? A Guide for Architecture Firm
- 4 hours ago
- 8 min read
When an existing building is renovated, extended or repurposed, one of the first questions an architecture team needs answered is simple, "What is actually there?" The original architectural drawings may show what was intended to be constructed, but buildings change over time. Walls move, doors are relocated, spaces are reconfigured, equipment changes and previous renovations may never have been incorporated into the original drawing set.
This is why accurate as-built drawings are so important. As-built documentation provides architects, designers, owners and project teams with a more reliable record of the building's existing conditions before new design work begins. For architecture firms working on renovations and existing buildings, this can reduce uncertainty, improve coordination and provide a stronger foundation for future architectural documentation.
What Are As-Built Drawings?
As-built drawings are architectural drawings that record the actual condition of a building rather than simply showing what was originally designed or intended to be constructed.
Depending on the project, as-built documentation can include:
Floor plans
Elevations
Building sections
Reflected ceiling plans
Wall locations and dimensions
Door and window locations
Room layouts
Equipment locations
Existing architectural details
Other verified building information
For older properties, reliable digital documentation may not exist. The available information might consist of old PDFs, CAD drawings, scanned plans, hand marked drawings, photographs or documentation created before subsequent alterations were made. In these situations, developing an accurate existing condition drawing set can become an important first stage of the project.
Why Are As-Built Drawings Important?
As-built drawings help architecture teams understand what actually exists before designing what comes next. This becomes particularly important during renovations because new architectural work must integrate with an existing building. If the underlying information is incorrect, those inaccuracies can carry forward into the new design and documentation. Accurate as-built information can therefore help reduce:
Design conflicts
Incorrect dimensions
Unnecessary redesign
Additional site verification
Documentation revisions
Coordination problems
Construction changes
Delays caused by unexpected existing conditions
As-built drawings cannot reveal every concealed building condition. However, they can significantly improve the quality of the existing-condition information available to the project team.
1. As-Built Drawings Create a Reliable Starting Point
Every renovation needs a starting point.
Imagine an existing drawing indicates that a room is six metres wide.
The actual constructed room is 224.41 inches wide.
That difference could affect cabinetry, equipment, circulation, furniture layouts, door positions and adjoining spaces.
When several discrepancies exist across a building, their combined effect can become significant.
Identifying these differences before progressing too far into the new design can reduce unnecessary rework later.
2. Construction Drawings and As-Built Drawings Are Not the Same
This distinction is important because construction drawings show what was planned or intended to be built, while as-built drawings document what was actually constructed and what currently exists.
Construction projects often evolve as contractors encounter unexpected site conditions. Materials may change, client requirements may develop, dimensions may be adjusted and details may be modified throughout the construction process.
If those changes aren't incorporated into the building record, the original architectural drawings gradually become less reliable.
This can become an even greater issue when a building has undergone several renovations over many years.
Key Differences Between Construction and As-Built Drawings
Construction Drawings | As-Built Drawings |
|---|---|
Show the intended design | Record actual/existing conditions |
Primarily developed for construction | Provide a record of the building |
Created before and during construction | Updated from verified information |
May not reflect every site change | Intended to capture relevant completed conditions |
Guide construction | Support future work on the building |
3. As-Builts Can Reduce Expensive Surprises
Discovering a discrepancy during the documentation stage is generally preferable to discovering it once construction has begun. Unexpected conditions can create a chain reaction:
Conflict → Investigation → Redesign → Revised Drawings → Additional Coordination → Potential Delay
Accurate as-built documentation doesn't eliminate every risk associated with an existing building. It does, however, help reduce avoidable uncertainty by giving the architecture team better information at the beginning.
4. As-Builts Help Compare Drawings With Actual Building Conditions
On some projects, the challenge isn't simply creating a new floor plan. The architecture team may need to establish:
What was originally documented?
What currently exists?
What has changed?
Existing architectural drawings can be compared with current information obtained from field verification, photographs, scans, point clouds or other available building information. Discrepancies can then be identified and incorporated into updated architectural documentation. This can be particularly valuable on large or complex renovation projects where several drawing sets have been produced over the building's lifetime.
5. As-Built Drawings Support Renovations and Adaptive Reuse
Existing buildings frequently change purpose.
An office may become a healthcare facility.
A residential property may be extended.
A commercial space may be divided into multiple tenancies.
A municipal building may require a new internal configuration.
A hotel or apartment development may undergo a major refurbishment.
Before designing these changes, the project team needs to understand the building they are working with. Accurate existing-condition documentation provides a foundation for that work.
6. As-Built Documentation Preserves Building Information
Building knowledge often exists with individual people.
A project architect remembers why a particular wall moved.
A contractor knows where an element was relocated.
A facilities manager remembers what happened during a renovation ten years earlier.
Eventually, those people may no longer be involved with the property.
Documentation creates a more permanent building record.
When another architect, contractor, owner or facilities team becomes involved, reliable as-built information can give them a much clearer starting point.
7. As-Built Drawings Can Support Future Projects
A building may undergo several renovations throughout its lifetime and good as-built documentation can therefore continue providing value long after the immediate project has finished. When future work begins, the architecture team may already have access to reliable information regarding:
Existing layouts
Dimensions
Wall locations
Doors and windows
Building sections
Previous alterations
Other documented architectural conditions
This can reduce the amount of existing information that needs to be recreated every time another project begins.
How Are As-Built Drawings Created?
The exact process depends on the building and the information available. A typical workflow may involve:
1. Collect existing documentation
This could include architectural PDFs, CAD files, Revit models, historical drawings and previous renovation information.
2. Capture or obtain current building information.
Depending on the project, this may include:
Site measurements
Field verification
Photographs
Laser scanning
Point clouds
Matterport information
Markups and redlines
3. Compare the information
Existing drawings are reviewed against the verified building conditions.
4. Identify discrepancies
Differences between the available documentation and existing conditions are identified.
5. Update the architectural documentation
The verified information is incorporated into updated CAD drawings, Revit models or other required project documentation.
6. Quality review
The updated documentation should be checked for consistency and alignment with the information provided. This process can be especially important on larger buildings where hundreds of existing conditions may need to be reviewed.
Can Point Clouds Be Used for As-Built Drawings?
Point-cloud data can provide highly detailed spatial information about an existing building and can be used as a reference when developing as-built drawings and existing condition models. The point cloud itself, however, isn't the finished architectural documentation. Architectural information still needs to be interpreted, modelled and documented according to the requirements of the project.
Can As-Built Drawings Be Created in Revit?
Yes, verified information about existing conditions can be used to develop an accurate Autodesk Revit model. Depending on the project requirements, the model can then be used to generate:
Existing floor plans
Elevations
Sections
Reflected ceiling plans
Schedules
Architectural details
Other required documentation
This can provide architecture teams with a digital base for subsequent renovation or design development.
What Is the Difference Between As-Built and Existing-Condition Drawings?
The terms are often used interchangeably, although technically there can be a distinction. As-built drawings traditionally document how a construction project was actually completed, including relevant changes made during construction. Existing condition drawings document the current state of an existing building, which may include modifications made many years after the original construction.
For older renovation projects, existing condition documentation may therefore be a more accurate description. In both cases, the objective is similar: Give the project team a reliable representation of the building's actual condition.
What Happens When As-Built Drawings Are Inaccurate?
Inaccurate existing-condition information can create problems throughout a project. These may include:
Incorrect dimensions: Design decisions are made using measurements that don't match the building.
Design conflicts: Proposed elements clash with existing conditions.
Additional site verification: The project team repeatedly returns to verify information.
Documentation revisions: Drawings need to be updated after discrepancies are discovered.
Construction changes: Conditions discovered during construction require the design to be reconsidered.
Project delays: Questions and redesign can affect the project programme.
This is why existing condition documentation shouldn't be treated simply as an administrative task, It is part of establishing a reliable foundation for the project.
Can Architecture Firms Outsource As-Built Drawing Production?
Yes, it's a practical and widely used option for many firms. Developing existing condition documentation can require considerable production time, particularly for large buildings or projects involving significant amounts of survey and historical information. Architecture firms can use external production resources to assist with tasks such as:
Developing existing-condition drawings
Converting verified field information into architectural documentation
Updating Revit models
Producing CAD drawings
Comparing previous drawings with current conditions
Incorporating markups and redlines
Developing elevations and sections
Organising drawing packages
Documenting identified discrepancies
The architecture firm remains responsible for project direction, design decisions, verification requirements and final review. The outsourced production team provides additional capacity to help process and document the available information.
Experience Matters When Documenting Existing Buildings
As-built projects require more than simply tracing an old drawing. The information may come from multiple sources and may not always agree, a drawing might show one condition, while a scan shows another. Site photographs may identify an alteration that isn't represented in either of the historical drawing sets.
This is where experience with architectural documentation and existing condition projects becomes important. The production team needs to understand what information has been verified, what remains uncertain, and what needs to be raised with the architecture team rather than assumed.
As-Built Documentation Support From Lynx Professional Services
Lynx Professional Services has more than 15 years of experience supporting architecture and interior design firms with architectural production and documentation.
Our teams work with architecture firms across the USA and Canada, supporting projects in Autodesk Revit, AutoCAD and other architectural software.
For existing-building and as-built projects, Lynx can support the development of architectural documentation using the verified information supplied by the client and project team.
Our approach is to work within the architecture firm's:
Drawing standards
Templates
File structures
Project requirements
Documentation procedures
Review processes
The architecture firm retains control of the project while Lynx provides additional architectural production capacity.
Frequently Asked Questions About As-Built Drawings
What are as-built drawings?
As-built drawings document the actual or verified condition of a building rather than simply showing what was originally intended to be constructed.
Why are as-built drawings important?
They provide architects and project teams with more reliable existing-condition information for renovations, alterations, facility management and future building work.
Are as-built drawings the same as construction drawings?
No. Construction drawings show the intended design. As-built drawings are intended to record relevant conditions as actually constructed or subsequently verified.
Do I need as-built drawings for a renovation?
Accurate existing-condition information is particularly valuable for renovations because the proposed design needs to integrate with an existing building. The documentation required depends on the individual project.
Can old architectural drawings be used as as-built drawings?
Old drawings can provide useful reference information, but they shouldn't automatically be assumed to represent current conditions. The building may have been altered since those drawings were produced.
Can point clouds be used to create as-built drawings?
Yes. Point-cloud data can provide detailed spatial information that can be used as a reference when developing as-built drawings and existing-condition models.
Can as-built drawings be produced in Revit?
Yes. Verified existing-condition information can be developed into a Revit model and used to produce floor plans, elevations, sections and other architectural documentation.
Can as-built drawing production be outsourced?
Yes. Architecture firms can outsource defined production tasks involved in developing existing-condition drawings and models while maintaining project direction, verification and final review internally.
Who is responsible for verifying as-built information?
This depends on the project agreement and scope. Architecture firms should clearly establish who is responsible for site verification, survey information, documentation production and final approval before work begins.
