Design development is the phase of the design process where a rough concept turns into a buildable plan. It sits between schematic design and construction documents, and it’s the stage where every important decision (materials, dimensions, building systems, finishes) gets locked down. In plain terms? It’s where the design stops being an idea and starts becoming a real, coordinated set of drawings and specifications.
We’re Ark & Mason, a Vancouver design-build firm, and design development (or DD, as most of us call it) is one of the busiest phases we run. Here’s what actually happens in it, who’s involved, and why it matters so much to your final result.
What is the meaning of design development?
Design development is the architectural design phase that refines an approved schematic design into a detailed, coordinated design package. The drawing set gets more precise. Room sizes are confirmed. Materials are chosen. The structural engineer, the mechanical team, and the architect all start working from the same page, literally.
The American Institute of Architects puts it simply. According to the AIA, “Design development (DD) services use the initial design documents from the schematic phase and take them one step further.” That’s the whole idea. You take the proposed design you already agreed on and you push it toward something you can actually price and build.
It helps to know where DD lands in the architectural design process. There are usually five phases: schematic design, design development, construction documents, bidding or tender, and construction administration. The design development stage is the bridge in the middle. It’s where the design concept meets reality.
What is included in design development?
Design development includes refining the design across every discipline and producing design development documents that define the project in detail. Think floor plans with confirmed dimensions, reflected ceiling plans, elevations, outline specifications, and early cost estimates. The deliverable at the end is a coordinated set of design development drawings that a contractor and the construction documents phase can build on.
Here’s what we’re typically nailing down during the DD phase:
- Interior and exterior materials and finishes, chosen and specified rather than just sketched.
- Building systems: structural, mechanical, electrical, plumbing, fire protection, and lighting design, all coordinated so they don’t clash.
- Custom millwork and cabinetry, which we draw in detail because we fabricate it in-house.
- Layouts, room sizes, and the site plan, refined from preliminary design into something specific.
- An outline specification and updated cost estimates so the budget stays honest.
By the close of this phase, the design should be detailed enough that there’s very little guesswork left. A university facilities team describes the finish line well. Per Western Michigan University, “By the end of design development the design drawings and specifications are sufficiently complete to establish and define the facility’s size, function, configuration, spaces, the operation or use of equipment and the materials for all the principal building structures and systems.” Long sentence. Big payoff. It means the hard decisions are made before anyone starts producing construction documents.
Why is design development important?
Design development is important because it’s where design changes are cheap and easy, before they become expensive and disruptive. Move a wall on a DD drawing and you’ve spent five minutes. Move that same wall during construction and you’ve spent thousands. The whole point of the design development process is to surface conflicts early and align the design team around final design decisions.
Ever wonder why a project that looked great on paper goes sideways on site? Usually it’s because someone skipped the hard coordination work that belongs in DD. The mechanical ducts and the structural beams want the same ceiling space. The lighting design fights the millwork. None of that is fun to discover when the drywall is already up.
This is also where building code compliance gets baked in. We’re checking the proposed design against the BC building code and flagging anything that needs to change while it’s still drawings. For us, that integration is the point. Because we handle both design and construction under one roof, the choices we make in design development are choices we’ll have to stand behind on site. That keeps us honest. You can see how this fits into our broader approach on our process page.
Design development vs construction documents: what’s the difference?
The difference is purpose. Design development decides what the project is. The construction documents phase explains exactly how to build it. DD answers “what materials, what systems, what sizes.” Construction documents translate those answers into precise, dimensioned drawings and specifications a builder uses on site.
One way we describe it to clients: design development refines the design, and construction documentation records it. By the time you reach final construction documents, the creative decisions are done. The construction drawings are about coordination, detail, and instructions, the technical layer used in construction and permitting. If you want the deeper version of how we produce that set, our construction documentation services page walks through it.
Can construction documents be created before DD is finished? Not well. Drawing detailed construction documents on top of an unresolved design just means redrawing them later. That’s why we treat the handoff from DD to CD as a real milestone, not a blur.
Who creates design development, architects or engineers?
Both. Design development is led by the architect or designer, but it’s genuinely collaborative, and the engineers are right there in it. The architect coordinates the overall design while the structural engineer, MEP consultants, and other members of the design team develop their systems within it.
On our projects the cast usually includes the lead designer, a structural engineer, mechanical and electrical consultants, and our own millwork and construction management people. Why bring the builders in this early? Because constructability matters. A design professional who has never had to build the thing can specify something that’s a nightmare to install. We’d rather catch that in a meeting than on a Friday afternoon on site. This kind of engineering coordination is something we manage directly as part of our design development service.
How long does the design development phase typically take?
The design development phase typically takes a few weeks to a couple of months, depending on the size and complexity of the construction project. A single clinic fit-out might wrap DD in three or four weeks. A large multi-room facility with complex building systems can take considerably longer.
What drives the timeline? Decision speed, mostly. When a client reviews materials and finishes promptly, DD moves fast. When approvals stall, so does everything downstream. We try to front-load the decisions that have the longest lead times, custom millwork and specialty equipment especially, so a slow supplier doesn’t quietly become the critical path. Honest scheduling here protects the whole project delivery.
Frequently asked questions
What is considered design development?
Design development is considered the phase where an approved schematic design is refined into detailed, coordinated drawings and specifications. It covers material selections, room sizes, building systems, and outline specifications. It ends when the design is defined clearly enough to begin producing construction documents.
What deliverables do you get at the end of design development?
At the end of design development you get a coordinated set of design development documents: refined floor plans, reflected ceiling plans, elevations, an outline specification, material and finish selections, and updated cost estimates. Together they define the project’s size, layout, materials, and systems. This package becomes the foundation for the construction documents phase.
Is BIM used in the design development phase?
Yes, building information modeling is commonly used during design development and carries straight through into the construction document phase. A 3D model lets the design team coordinate structural, mechanical, and architectural elements and catch clashes before construction. It also keeps drawings and specifications consistent as the design changes.
When does the design development phase end and construction documentation begin?
Design development ends once the major design decisions, materials, systems, dimensions, and layouts, are finalized and approved. Construction documentation begins right after, translating those decisions into the detailed construction drawings and specifications used to build and permit the project. The cleaner the DD handoff, the smoother the construction documents go.
