What Is a 30% CD?

Architects on commercial buildings usually inherit a percentage from the owner’s project manager: 30, 60, 90, and 100 percent of construction documents. By the time CDs start, schematic design has fixed the plan diagram and design development has sized the major systems. Thirty percent of that CD effort looks like dimensioned plans, a structural grid, preliminary elevations and sections, single-line MEP, and an outline specification.

Civil and federal practice often skips the SD/DD/CD labels and submits "30% design." USACE, NAVFAC, and many DOTs expect that package to show design criteria, general arrangements, typical sections, and a preliminary cost, with plenty of the building or roadway still undecided. If a comment log from a 30% design review demands fabrication-level details, the reviewer is applying a later gate to an earlier set.

A solid 30% CD building set lets someone walk the floor plan and see the structural bay, the exit stairs, the shaft locations, and the rooms that drive equipment size. Wall types may be typical rather than complete. Details are the ones that set the envelope or the structure, not every condition. The project manual is usually an outline or a short-form spec, enough to price systems and not enough to buy products.

What does not belong yet is a fully coordinated reflected ceiling plan, a complete door schedule, or a specification section that names a basis of design for every product. Those land at 60 and 90 percent. The estimate at 30 percent should still carry design contingency, because the set will move.

The useful comments at 30 percent are about arrangement, system choice, code strategy, and cost. A comment that asks for a missing hanger detail will be obsolete once the ceiling coordination happens. Teams that spend the review window marking missing annotation, instead of challenging the structural grid or the air-handler location, lose the last cheap moment to change the building.

The other failure is a set that is labeled 30% and drawn to 10%. Plans that are still diagrammatic cannot support a real cost check or a constructability pass. The submission requirements in the design contract, or the agency’s CAD/BIM manual, are the checklist. A percentage in the title block does not define the package by itself.

Thirty percent comments need a written response, the same way a later review does. Unanswered comments reappear at 60%, usually after the team has drawn them into the set the wrong way. Owners who track a comment log with a disposition (accept, clarify, or defer) get a 60% set that is actually further along.

Scope that is still an allowance or an alternate should be named as such on the 30% estimate. Letting an undefined kitchen, lab, or site package hide inside a lump-sum line makes the 60% estimate look like a blowout when it was a gap at 30.