SD, DD & CD in Construction: Meaning, Uses & Comparison

In construction and architecture, projects do not move from an idea directly into construction. They pass through different design stages, and each stage adds more clarity, detail, and documentation.

Three common terms used in this process are SD, DD, and CD.

• SD means Schematic Design.
• DD means Design Development.
• CD means Construction Documents.

Together, SD, DD, and CD explain how a building design moves from an early concept to a detailed set of drawings that can be used for pricing, permits, bidding, and construction.

These phases are commonly used in architectural design services. AIA explains that schematic design helps establish project goals and design concepts, design development takes the approved concept further with architectural, structural, mechanical, electrical, and plumbing details, and construction documents provide the information required for contractors to price and build the project.

Let’s understand each phase in a simple way.

SD vs DD vs CD: Quick Comparison

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This is why SD, DD, and CD are often called design phases or construction document phases. They help teams move step by step instead of trying to solve every design and construction question at once.

What Is Schematic Design (SD)?

Schematic Design, or SD, is the first major design phase where the basic direction of the project is developed.

At this stage, the design is still broad. The goal is not to finalize every wall type, ceiling detail, door schedule, or system routing. The goal is to understand the project’s size, layout, form, function, and relationship to the site.

During schematic design, the architect usually works with the owner to understand the project goals, space requirements, budget expectations, site conditions, zoning restrictions, and overall design direction. AIA notes that schematic design commonly includes study drawings or other media that show concepts, spatial relationships, scale, and form for owner review.

What are SD drawings?

SD drawings are early-stage design drawings used to communicate the project concept.
Schematic design documents include the following include:

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These drawings are not usually detailed enough for construction. Instead, they help the owner and project team understand what the building may look like, how spaces may be arranged, and whether the concept aligns with the project goals.

What are Schematic Design (SD) documents?

SD documents are the drawings, diagrams, narratives, and early project information created during the schematic design phase.

They may include the SD drawings, design narrative, preliminary code review, early cost estimate, area summary, and basic material or system ideas.

The purpose of SD documents is to support early decision-making. Once the owner approves the schematic design, the project usually moves into the DD phase.

What Is Design Development (DD)?

Design Development, or DD, is the phase where the approved schematic design is developed into a more detailed and coordinated design.

If Schematic Design is about selecting the direction, Design Development is about making that direction more realistic.

In this phase, the design team begins to define architectural elements, structural systems, MEP systems, dimensions, materials, and technical requirements in more detail. AIA describes DD as the phase that takes schematic design one step further and lays out mechanical, electrical, plumbing, structural, and architectural details.

What are DD drawings?

DD drawings are design development drawings that show a more complete and detailed version of the project..

They usually include more dimensions, clearer sections, developed elevations, door and window information, material direction, and early coordination between disciplines.

Design Development drawings may include:

The DD stage is important because it connects the early design idea with the technical requirements needed to make that idea buildable.

What is a DD set?

A Design Development set is the collection of design development drawings and documents issued at the end of the DD phase.

A DD set is more detailed than an Schematic Desing set, but it is usually not as complete as a Construction Document set. It helps owners, consultants, and sometimes cost estimators review the design before the project moves into final construction documentation.

The DD set may be used for design review, pricing updates, owner approval, consultant coordination, and early constructability discussions.

What Are Construction Documents (CD)?

Construction Documents, or CD, are the detailed drawings and specifications prepared for pricing, permitting, bidding, and construction.

This is the stage where the design is documented with enough detail for contractors and authorities having jurisdiction to understand the work.

AIA explains that once the owner and architect are satisfied with the design development documents, the architect moves forward with construction documents. These drawings typically include specifications for construction details and materials, and the CD set provides information required for contractors to price and build the project.

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What are Construction Document (CD) drawings?

CD drawings are the final construction drawings prepared as part of the construction document phase. The final, highly detailed set of blueprints used by builders to price, permit, and construct a building.

A complete CD set typically includes

CD drawings are much more detailed than SD or DD drawings. They are meant to communicate how the project should be built, not just what the design idea looks like.

What is a Construction Document set?

A CD set is the complete set of construction documents issued for permit, bidding, pricing, or construction.

Depending on the project stage, you may hear terms like:

A 100% CD set usually means the construction documents are considered complete for their intended use. However, the exact meaning can vary depending on the contract, project type, and submission requirement.

Where SD, DD, and CD Fit in the Construction Process

SD, DD, and CD are part of the larger design and construction process. A typical project may move through these stages:

The exact process can change based on the project delivery method, contract, owner requirements, and project type. But SD, DD, and CD remain common terms used to describe how design documentation matures.

How BIM Supports SD, DD, and CD Drawings

Building Information Modeling can support each stage of SD, DD, and CD by helping the project team develop drawings from a coordinated digital model.

In the Schematic Design phase, BIM may be used for early massing, space planning, area studies, and design visualization.

In the Design Documentation phase, BIM can help develop architectural, structural, and MEP systems in a more coordinated way. This is where the model starts carrying more useful information about building elements, systems, materials, and spatial relationships.

In the Construction Document phase, BIM can support the production of coordinated plans, sections, elevations, schedules, and details from the model. Since drawings are generated from the model environment, updates can be managed with better consistency across views when the model is properly maintained.

BIM does not remove the need for design judgment, documentation standards, or technical review. But it can make the transition from SD to DD to CD more structured and easier to manage.

In Summary
SD, DD, and CD are three important design stages in construction.

• SD, or Schematic Design, defines the early concept –  It helps the owner and project team understand the basic layout, form, scale, and design direction.
• DD, or Design Development, develops the approved concept – It adds more technical detail, dimensions, materials, systems, and coordination.
• CD, or Construction Documents, prepares the final drawing set – It includes the detailed drawings and specifications needed for pricing, permits, bidding, and construction.

A simple way to remember the difference is:
SD shows the idea | DD develops the idea | CD documents the idea for construction

FAQs SD, DD & CD in Construction