How to Develop As-Built Drawings of Existing Structures?

Whether for renovations, maintenance, or future design planning, accurate as-builts provide a visual and technical reference for architects, engineers, facility managers, and property owners. But how exactly do you develop these drawings for existing structures? Let’s walk through the process.

What Are As-Built Drawings?

As-built CAD drawings are detailed representations of a structure as it exists today, capturing any changes made during construction, additions, or discrepancies from the original design. Unlike design blueprints, as-builts reflect the real-world outcome of a project, making them essential for lifecycle management of any built asset.

Step 1: Site Survey and Data Collection

The first step in developing as-built drawings is conducting a comprehensive site survey. Depending on the project scope, this can be done using:

• Manual measurements (for small-scale projects)
• Total stations and GPS tools (for accuracy in large structures)
• 3D laser scanning (LiDAR) and photogrammetry (for complex or detailed structures)

The goal is to capture all dimensions, elevations, features, utilities, and any architectural or structural changes not reflected in the original plans.

Step 2: Document Observations

Surveyors or engineers must carefully document on-site findings, including:

• Wall placements, window and door locations
• Ceiling heights, beam positions, and floor levels
• Plumbing, HVAC, and electrical installations
• Deviations from original blueprints
• Damages, wear, or alterations

Photos, notes, and sketches are commonly used in this phase to ensure no detail is overlooked.

Step 3: Draft the As-Built Drawings

Once all data is collected, CAD or BIM software is used to create precise as-built drawings. Key elements in the drawing include:

• Floor plans and elevations
• Sections and details
• Electrical and mechanical layouts
• Legends, symbols, and annotations

Drawings should be layered, labelled clearly, and formatted to match industry standards or client requirements.

Step 4: Review and Validation

It’s important to cross-verify the as-built drawings with on-site measurements and stakeholder feedback. Engineers, architects, and clients may review the drafts to ensure all modifications are accurately captured. 

Step 5: Final Delivery

After validation, the final set of as-built drawings is delivered in the required formats, typically PDF, DWG, or BIM models. These ocuments are archived for future reference and become part of the structure’s official documentation. 

Developing accurate as-built drawings requires a combination of technical skills, advanced tools, and meticulous fieldwork. When done right, as-builts offer a reliable roadmap of a building’s current condition, essential for maintenance, renovation, and smart facility management. 

As-built drawings are a crucial part of land survey CAD drafting. They represent the final built condition of a site or structure, capturing any changes made during construction compared to the original design. The CAD services provide accurate and updated details of features like buildings, utilities, roads, and elevations, helping engineers, architects, and property owners maintain precise records for future planning, maintenance, or renovations.

Need help developing as-builts for your project? Partner with Polosoft Technologies experts who combine technology and experience for precision results.