With design-build, one company handles both the design and the construction under a single contract. With design-bid-build, you hire a designer first, then put the finished plans out to bid and hire a separate contractor. Design-build is usually faster and gives you one point of responsibility. Design-bid-build gives you competing bids on a fixed set of plans, but takes longer and puts you in the middle if problems come up.
How design-bid-build works
Design-bid-build is the traditional way to build. It happens in three steps, one after the other:
- Design – you hire an architect or designer to draw up full plans.
- Bid – contractors price those plans, and you choose one.
- Build – the contractor builds what was drawn.
Because the designer and the builder work under separate contracts, you sit between them. If the plans miss something on site, or the bids come in over budget, the design often has to go back for changes before work can carry on.
How design-build works
With design-build, design and construction sit with one team from day one. At NJ Design & Build, that means:
- Consultation – we learn your goals, your property and your budget.
- Design and plan – architectural plans, 3D visuals, material choices and a clear cost estimate, with the builders involved from the start.
- Permits – we prepare and handle the permit applications and approvals.
- Construction and handover – our team builds, inspects and hands over the finished space.
Because the people pricing and building the job are in the room while it is being designed, cost and buildability are checked as the design develops – not after it is finished.
Which is faster?
Design-build is usually faster, because design and construction planning overlap instead of happening one after the other, and there is no separate bidding stage.
The best-known research on this comes from a 2018 study by the Construction Industry Institute and the Charles Pankow Foundation, published by the Design-Build Institute of America. It looked at 212 completed U.S. building projects. Compared with design-bid-build, design-build projects were delivered 102% faster from design through completion, and construction itself was 36% faster.
One honest note: that study looked mostly at commercial, industrial and multi-unit buildings, not single-family homes. The same principle applies to a home remodel or addition, but your own timeline will depend on the size of the job and how long San Diego permits take.
Which costs less?
The upfront price is often similar. The bigger difference is how much the cost changes once work starts. In the same 2018 study, design-build projects cost only 0.3% less per square foot than design-bid-build, but they had 3.8% less cost growth – meaning fewer budget surprises during the build.
Design-bid-build can give you a lower first number, because contractors compete on price. The risk is that the lowest bid can rise later through change orders, especially if the plans left gaps.
Design-build vs design-bid-build at a glance
| Design-build | Design-bid-build | |
|---|---|---|
| Contracts | One | Two or more (designer and contractor) |
| Who is responsible if something goes wrong | One team | Often split between designer and builder |
| Speed | Usually faster – design and planning overlap | Slower, step by step |
| Price | Cost checked during design, fewer surprises | Competitive bids on finished plans, more risk of change orders |
| Your role | One point of contact | You coordinate between parties |
When design-bid-build can still make sense
Design-bid-build can be the right choice if you already have finished, permit-ready plans from an architect, if you want several contractors to price exactly the same drawings, or if a public or institutional client requires competitive bidding.
Which is best for a San Diego home project?
For most San Diego homeowners planning a remodel, an home addition, an ADU or a new home, design-build is the simpler route. You get one team that designs to your budget, deals with the permit process and builds what it designed. That is why it suits projects such as ADUs, where design, permits and construction are closely tied together – see our ADU builders in San Diego page.
If you are weighing up a project, talk to NJ Design & Build about our design-build services in San Diego, or about working with us as your general contractor in San Diego if you already have plans.
Frequently asked questions
What is the main difference between design-build and design-bid-build?
Design-build uses one contract for both design and construction. Design-bid-build uses separate contracts: you hire a designer, then take the finished plans to bid and hire a contractor.
Is design-build cheaper than design-bid-build?
Not always on the first price. Research published by the Design-Build Institute of America found design-build costs were close to design-bid-build per square foot, but with less cost growth during construction.
Is design-build faster?
Usually, yes. Design and construction planning overlap, and there is no separate bidding stage. A 2018 industry study found design-build projects were delivered much faster overall than design-bid-build.
Can I use design-build for an ADU in San Diego?
Yes. Design-build works well for ADUs, because one team handles the design, the permit process and the construction.
What if I already have plans from an architect?
Then you can hire a general contractor to build from your plans. NJ Design & Build works both ways.
