What is design-bid-build in construction?
Design-bid-build is a project delivery method where the owner hires an architect or engineer to finish the design first, then bids the complete drawings to contractors and awards a separate construction contract. Much public work uses it because every bidder prices the same documents. The owner generally warrants the design's adequacy to the contractor.
Design-bid-build (DBB) is the oldest and most familiar delivery method in U.S. construction. It runs in three steps, in order. The owner hires a designer to produce complete contract documents. The owner puts those documents out for bid. The owner signs a construction contract with the selected general contractor, usually the lowest responsive and responsible bidder. The designer and the builder each have their own contract with the owner, and no contract with each other.
Much public work is delivered this way because it is easy to explain to taxpayers: everyone bids the same drawings, and the price is set before the shovel hits the ground.
How design-bid-build works on a real job
A school district wants a $6 million gym addition. It hires an architect, who spends months on schematic design, design development, and construction documents. The district then issues an invitation to bid. Six general contractors pull plans, collect sub quotes, and submit sealed bids on bid day. The low bidder that meets the requirements signs a contract, usually a lump sum contract, and builds what is drawn.
During construction the architect answers RFIs, reviews submittals, and certifies pay applications. If the drawings are missing something, the contractor asks, and the fix comes as a change order paid by the owner. The contractor's leverage is the bid set: anything not shown or reasonably implied is extra work.
Pros and cons for contractors
| For the contractor | Against the contractor |
|---|---|
| Clear scope to price: you bid what is drawn | Price competition squeezes margin |
| Design errors are generally the owner's risk | Little input on constructability before bid |
| Familiar contracts such as AIA A201 | Adversarial setup between designer and builder |
| Open to any qualified bidder | Long total timeline because design and construction do not overlap |
Common disputes
- Incomplete drawings. Gaps in the bid set turn into RFIs, then change orders, then arguments over whether the work was reasonably inferable from the documents.
- Buying the job. A bidder who leaves scope out to win spends the job chasing changes. Bid clarifications and exclusions help keep it honest.
- Bid shopping after award. Subs who priced the job on bid day sometimes see their numbers shopped to others.
- Schedule. Because design must finish first, owners in a hurry sometimes push contractors to compress construction, which raises delay claim risk.
Related terms
Compare DBB with design-build, construction management at risk, and IPD. For public work bidding steps, see how to bid public construction projects. Smart Business Automator's public works contractor automation keeps bid documents, addenda, and compliance paperwork together.
Frequently asked questions
Is design-bid-build the same as hard bid?
Close. Hard bid describes the competitive, fixed-price bidding step. Design-bid-build describes the whole sequence of design, then bid, then build.
Who is responsible for design errors in design-bid-build?
Generally the owner, who warrants the adequacy of the design to the contractor, and then looks to its designer. The contract language controls.
Why do public owners use design-bid-build?
It gives every bidder the same documents, supports competitive low-bid laws, and keeps a clear separation between the designer and the builder.
Can a contractor be involved in design under DBB?
Usually not before bid. Some owners hire a contractor separately for preconstruction reviews, but that moves toward CM at risk.
