Understanding shop drawings, construction drawings and as-built drawings

A construction drawing, also called a building plan, is a part of the preconstruction stage and serves as a crucial deliverable to begin a construction project. They are prepared by architects to represent architectural elements and specifications before onsite work begins. Some construction drawings are also called “Issued for Construction (IFC)” drawings. These are approved drawings and used for actual construction purposes. Construction documents are prepared by architects or designers before the bidding process and serve as official contract deliverables.

Construction drawings are used for tender, for a contract between contractors and owners, or actual construction. Construction drawings need to be easy and clear for reading purposes, as any misunderstanding can lead to delays or errors. Construction documents are enriched by specification documents that include standards, techniques, and materials that need to have adhered to for site construction.

Construction drawings also include data from other trades including structural engineers, HVAC specialists, electrical and plumbing engineers, and fire safety professionals. The level of information and external inputs would depend on the project scale. A set of construction drawings includes:

• Floor / Roof plans – general arrangement drawings to project an overview of the building
• Elevation drawings – for detailed information on sections, plans, and external finishes
• Sections – to provide detailed information on floors and walls including levels and heights
• Part details – including junctions and connections or details on material changes for building elements
• Door or Window schedules – listing windows and doors with the required information sets
• Drainage and external works
• Landscaping and Furniture plans
• Reflected ceiling plans

Some common types of construction drawings are:

Floor Plan Construction Drawing

• Room names
• Dimensions and scale
• Wall size – external and internal
• References to detailed drawings and section lines
• Details on materials and specifications including notes
• HVAC, electrical, plumbing, and fire-safety information
• Various building levels

Elevation Construction Drawing

• Drawing scale
• Dimensions
• Floor levels and ground level
• Finishes and Cladding
• Slope, Roof shape, and materials

Sectional Construction Drawing

• Dimensions and Scale
• Size of partitions and exterior and interior walls
• Location of elements like beams, columns, etc.
• Information on stairs
• Detail drawing references
• Material details, notes, or specifications
• HVAC, electrical, and fire safety information
• Building level
• Information on foundations

Detail Drawings

Detail drawings are created on a 1:20 or 1:10 scale based on the project size and information contained within the drawings. Detail drawings demonstrate:

• Complex build parts
• Junctions
• Typical details

Construction drawings help architects and architectural firms during the approval process, bidding process and handover to contractors. They help to:

• Preserve work speed and productivity
• Reduce unnecessary costs and material waste
• Improve phase-by-phase project monitoring
• Promote prefabrication
• Encourage future planning and decision-making through data accuracy and completeness
• Collaborate better, and to stay connected and informed
• Streamline project execution to complete projects on time and within budget
• Save significant amounts of money and time through quick and effective fault correction

Shop drawings are important for manufacturers or fabricators to represent design intent with detailed plans. They help in the fabrication process by providing important information including that on manufacturing, assembly, and installation of building components. Shop drawings are produced by the contractors subcontractors, fabricators, or manufacturers.

Shop or fabrication drawings are used for prefabrication or onsite installation of components. With shop drawings, fabricators or manufacturers can figure out material types for components and installation dimensions.

Details that need to be included in shop drawings include:

• Dimensions, connection details, and other special instructions for fabrication
• Tags and dimensions of components
• Clearance and assembly details
• Section views and notes on deviations, changes, and dimensions
• Title block with project number, name, legends, and abbreviations
• Information regarding erection and installation
• Construction document comparisons for quick approvals from engineers or architects
• Data of initial drawings and revisions
• CAD drawings of the fabricated component with various angles
• Step-by-step assembly or installation with diagrams, connections, and materials
• References that point to prefabrication with specifications and requirements from the original design
• Notes on dimensions at the job site for review and verification before fabrication and installation

Shop drawings help onsite personnel in accurate and precise installation of building components as well as fabrication. They help in:

• Getting an accurate design model, optimized schedules, efficient cost estimates, and quantity takeoffs
• Improving production quality and efficient handover
• Effective communication and collaboration across multiple activities
• Defining the roles and responsibilities of stakeholders
• Improving coordination to reduce risks and liabilities
• Enhancing engineering analysis and accuracy
• Augmenting the construction document submittal process for construction and renovation

An as-built drawing can be a document of a record or a drawing created and delivered by architects, designers, or contractors after project completion. As-built drawings can represent and support thousands of building processes. These drawings can be used to manage the lifecycle of the project after construction is over. As-built drawings are deliverables that simplify comparisons and contrasts between the design and final specifications. They include all the modifications done during the construction project.

As-builts are used for the following purposes:

• Get the right set of information for sub-contractors
• With a complete record of change, teams can solve issues quicker and owners can save costs and speed up operations
• As-builts are requested by government agencies to issue permits
• With a complete record of project changes, owners can visualize what is built to improve the renovation process

As-built drawings need to include the following details:

• Record scale changes or utilize original scale drawings
• Use clear descriptions and labels
• Include modifications in dimensions, sizes, materials, locations, fabrication, and installation data
• Modification dates
• Record changes as per the final inspection
• Attach appendices and shop drawings
• Additional work done that is deemed extra to the original plan

As-built drawings deliver the following benefits for key stakeholders:

• Faster, efficient, and on-time renovations and demolition
• Improvements in process hazard analysis and process safety management
• Better building management by location, repairs, specific materials, and layout
• Assist project managers assign tasks, improve operations, and resolve unanticipated problems
• Track project progress, troubleshoot construction issues, set realistic deadlines, and provide estimates
• Faster subcontractor onboarding for review design, issue identification, comparing final and initial design, and completing tasks efficiently