Design
Step 2 in the construction process
What happens
Once feasibility gives a green light, Design translates an idea and a budget into drawings and specifications precise enough to price, permit, and build from. It moves through stages that get progressively more detailed and progressively harder to change, from a rough concept toward a fully coordinated set of construction documents. Schematic Design (SD) comes first: the architect, along with structural and MEP (mechanical, electrical, plumbing) engineers, blocks out the big picture, footprint, floor plan, general systems approach, rough square footage, and the owner reviews and signs off before more detail gets added on top of it. Design Development (DD) follows, where the architect and engineering consultants add real substance to that shape: material selections, the actual structural system, real equipment sizing. If a preconstruction manager or estimator has been brought in this early, this is where a real cost check happens, not the rough number from feasibility, and where value engineering conversations trade one material or system for another to hit budget while there's still room to do it cleanly. Construction Documents (CD) come last: the full set of drawings and specifications detailed enough for a contractor to actually build from and a permitting authority to review, checked internally along the way through clash detection (using BIM software to catch a duct routed straight through a structural beam on a screen, instead of in the field) and constructability reviews, where a contractor or estimator sanity-checks the design against how it will actually get built. Running alongside those three stages, a coordination process never really stops: structural, mechanical, electrical, and plumbing engineers each develop their own systems somewhat independently, and someone, often a BIM/VDC specialist, has to keep merging those models together to catch conflicts before they're locked in. Code compliance runs alongside all of it too; a building designed without permitting requirements in mind from the start usually needs expensive rework once Design meets Permitting, rather than a quick rubber stamp.
How long this takes
Design can take up a large share of a complex project's overall schedule, sometimes rivaling Construction itself. A simple building might move through all three design stages in a few months; a large hospital or high-rise can take a year or more, with code research and agency pre-review meetings adding months on top of that. What stretches it: an owner who keeps changing their mind mid-design, engineering disciplines that aren't coordinating well with each other, and multiple rounds of revisions driven by code issues. What compresses it: a decisive owner, and delivery methods like Design-Build that let design and early construction proceed on parallel tracks instead of waiting on each other.
Why this timing matters
Design is where the cost-of-change curve is still relatively low, but climbing fast. A floor plan changed during Schematic Design costs a few hours of redrawing. The same change made during Construction Documents, after structural and MEP engineers have already engineered around it, means re-coordinating several consultants' work at once. Made after the permit is filed, it can mean a formal resubmission and a new review cycle. This is exactly why owners are pushed to lock in the big decisions (floor plan, major systems) early: not because those decisions matter more than later ones, but because they're the last decisions that are still cheap to change.
Who's involved
Common misconception
People often assume the architect designs the whole building, structure included. In reality the architect is responsible for the layout, look, and code compliance of the spaces, while the actual structural system, the beams, columns, and foundation that hold the building up, is engineered by a separate structural engineer, with mechanical, electrical, and plumbing systems each belonging to their own engineering discipline. "The architect" is really shorthand for a team of several licensed professionals, not one person's design.
What can go wrong
The most common problem is poor coordination between engineering disciplines: a beam and a duct fighting for the same physical space, caught late instead of on a model months earlier. A close second is value engineering done too late or too hastily, cutting something structurally or functionally important just to hit a number, because nobody flagged the budget problem until the design was nearly finished. Skipping a contractor or estimator's input during Design is its own quiet failure mode: it produces a design that's technically buildable but wildly over budget the moment it actually gets priced, which then forces a rushed redesign instead of a planned one.
In practice
Design and Construction aren't always as separate as this section implies. Under fast-tracking or Design-Build delivery, a project can submit a foundation-only permit set and start site work while the rest of the building's design is still being finished, so Design and Construction genuinely overlap on the calendar rather than handing off cleanly. That overlap saves time, but it also means the strict phase order described here is a teaching model more than a description of how every real project actually runs.
Explore next