Design-Build vs General Contractor: What Bay Area Homeowners Need to Know

Understanding Your Two Main Options

When you are planning a major home project in the Bay Area, you need to decide who will manage it. The two most common approaches are hiring a design-build firm or hiring a general contractor. They sound similar, but they work in fundamentally different ways, and the choice affects your budget, timeline, and experience throughout the project.

This guide explains both models honestly so you can choose the right one for your situation.

How Each Model Works

The Design-Build Model

A design-build firm handles everything: design, engineering, permitting, and construction. You sign one contract with one company. Your designer and your builder work on the same team from day one.

Here is what the process looks like in practice:

1. Initial consultation. The firm assesses your property, listens to your goals, and provides a preliminary scope and budget range.
2. Design phase. Architects or designers on the firm’s team create plans. The construction team reviews every design decision for buildability and cost implications in real time.
3. Budget lock. Before construction begins, you receive a detailed, fixed-price construction contract based on the completed design.
4. Construction. The same company that designed your project builds it. There is no handoff, no reinterpretation of plans, and no gaps in communication.
5. Completion. One company is responsible for the final product. If something is wrong, there is one phone call to make.

The General Contractor Model

A general contractor handles construction only. You hire them after an architect has completed your plans. The GC bids on those plans, and if you accept, they build what the architect designed.

Here is what that process looks like:

1. Hire an architect. You find and hire an architect separately. The architect designs your project and produces construction documents.
2. Bidding. You send the completed plans to multiple general contractors for bids. This takes 2-4 weeks.
3. Contractor selection. You compare bids, check references, and select a GC.
4. Construction. The GC builds from the architect’s plans. Questions about design intent go back to the architect. Changes require coordination between you, the architect, and the GC.
5. Completion. The GC is responsible for construction quality. The architect is responsible for design accuracy. If something falls between those two areas, resolving it can be complicated.

Head-to-Head Comparison

Factor	Design-Build	General Contractor
Design included	Yes, under one contract	No, separate architect required
Number of contracts	One	Two or more (architect + GC)
Accountability	Single point	Split between architect and GC
Cost control	Builder shapes design to budget	Costs discovered at bid time
Timeline	Up to 33% faster	Sequential: design, then bid, then build
Change orders	Fewer (design/build alignment)	More common (design/build gaps)
Design flexibility	High, guided by cost awareness	Very high, but may exceed budget
Best for	Most residential projects	Projects with existing plans

Cost Implications: Where the Money Goes

The sticker price of a general contractor’s bid can look lower than a design-build proposal. But the total project cost tells a different story.

Costs unique to the GC model

Architect fees. Hiring an architect separately costs 8-15% of construction cost. For a $500K project, that is $40K-$75K in design fees before a single nail is driven.

Redesign costs. Architects design without real-time builder input. When bids come back higher than expected (this is common), the architect must redesign to reduce costs. Each redesign cycle costs time and money.

Change orders. When the builder encounters something the architect did not anticipate, a change order is issued. Industry data shows that projects using the traditional architect/GC model average 5-10% in change orders. On a $500K project, that is $25K-$50K in unexpected costs.

Coordination overhead. You are the project manager. Every decision that involves both design and construction requires you to coordinate between two companies. That takes time and, if miscommunication occurs, money.

Costs in the design-build model

Integrated design fees. Design fees are included in the overall project cost, typically 10-15% of the construction budget. You pay one number, and it covers everything.

Fewer change orders. Because the builder is involved in every design decision, plans are realistic from the start. Design-build projects typically see 1-3% in change orders vs 5-10% in the traditional model.

No bidding costs. You do not spend weeks collecting and comparing bids. The design-build firm provides one comprehensive proposal based on the design they helped create.

Research from the Design-Build Institute of America shows that design-build projects cost an average of 6% less than traditional delivery. That tracks with what we see in Bay Area residential projects.

Timeline Comparison

Time is money in the Bay Area, especially if you are paying for temporary housing during construction. Here is how the timelines compare for a typical whole-home remodel.

Traditional Architect + GC Timeline

Phase	Duration
Find and hire architect	2-4 weeks
Design and construction documents	3-6 months
Bidding and GC selection	4-8 weeks
Permitting	4-12 weeks
Construction	6-12 months
Total	12-22 months

Design-Build Timeline

Phase	Duration
Consultation and proposal	1-2 weeks
Design phase (with builder input)	2-4 months
Permitting (overlaps with design finalization)	4-12 weeks
Construction	6-12 months
Total	8-16 months

The design-build model saves time in three places. First, there is no separate architect search. Second, the bidding phase is eliminated. Third, design and pre-construction planning overlap because the same team handles both.

For a deeper comparison between design-build and the architect/contractor model, see our guide on design-build vs architect + contractor.

Accountability: The Biggest Practical Difference

When something goes wrong on a construction project (and something always does), who is responsible? This is where the two models differ most in day-to-day reality.

With a general contractor, problems that involve both design and construction create a gray area. The GC says the plans were unclear. The architect says the GC did not follow the plans. You are caught in the middle, paying for the resolution regardless of who is at fault. This scenario is not hypothetical. It happens on a significant percentage of traditionally delivered projects.

With design-build, there is one company responsible for everything. If the design has an issue, they fix it. If construction has an issue, they fix it. There is no finger-pointing because there is no one else to point at. This single accountability is the reason many Bay Area homeowners choose design-build, especially for large projects where the financial stakes are high.

Bay Area Considerations

Several factors specific to the Bay Area market favor one model or the other.

Complex permitting. Bay Area cities have notoriously detailed plan check requirements. A design-build firm that handles both design and construction has experience navigating these requirements as a unified process. When a plan checker requests a change, the designer and builder can assess the impact together and respond quickly.

High cost of delays. With Bay Area rental costs running $3,000-$6,000/month for temporary housing, every month of delay hurts. The 4-6 months that design-build saves on a typical project translates to $12K-$36K in avoided housing costs alone.

Labor market. The Bay Area construction labor market is competitive. Quality subcontractors are booked months in advance. Design-build firms with established subcontractor relationships can schedule trades earlier in the process because they know the project scope before plans are finalized.

Lot complexity. Bay Area lots are often small, sloped, or constrained by setbacks. Having the builder involved during design ensures that construction logistics (crane access, material staging, equipment paths) are considered in the design itself. An architect designing in isolation may create a beautiful plan that is logistically difficult or expensive to build on your specific lot.

When to Hire a General Contractor

Despite the advantages of design-build, there are situations where hiring a GC is the right call.

• You already have complete plans. If you have worked with an architect and have a full set of construction documents, hiring a GC to build them makes perfect sense. There is no reason to pay a design-build firm for design services you do not need.
• The project is primarily cosmetic. Painting, new flooring, fixture replacements, and other cosmetic updates do not need integrated design. A skilled GC or handyman can handle these efficiently.
• You want a specific architect. If there is a particular architect whose work you admire, hiring them independently and then finding a GC to build the design preserves that creative vision.
• Budget is tight. For smaller projects under $100K, the overhead of a design-build firm may not be justified. A competent GC and a draftsperson can handle straightforward projects cost-effectively.

How Custom Home’s Design-Build Process Works

At Custom Home Design and Build, we use a two-phase design-build process that gives you the benefits of integrated design and construction while maintaining full control at every step. To understand the full process, visit our process page.

Phase 1: Design. Our design team works with you to create a complete plan for your project. Our construction team reviews every decision for buildability and cost. You receive 3D renderings, detailed specifications, and a locked-in construction budget. You approve everything before moving forward.

Phase 2: Construction. With an approved design and fixed budget, we build. Because our construction team shaped the design, there are no surprises. The plan is buildable, the materials are specified, and the budget is accurate.

The phase separation is important. You are never locked into construction until you have seen and approved every detail. If Phase 1 reveals that a different approach (or a different scope) makes more sense, you have that information before committing.

For homeowners navigating custom home costs in the Bay Area, this process delivers the budget certainty that makes large projects manageable. You know the number before you break ground.

Making Your Choice

For most Bay Area homeowners planning a major project, design-build is the more efficient, cost-effective, and lower-risk approach. The integrated team, single accountability, and overlapping phases save time and money while reducing the coordination burden on you.

Hire a general contractor when you already have complete plans, when the project is small or cosmetic, or when you want to work with a specific independent architect.

The most important thing is to understand what each model requires of you. Design-build asks you to trust one team with both design and construction. The GC model asks you to manage the relationship between your architect and your builder. Choose the level of involvement that matches your time, expertise, and comfort level.