Should You Hire Separate Trades or Use a General ...

The Big Question: GC or Separate Trades for Your ADU?

One of the most consequential decisions you will make during your ADU project is whether to hire a general contractor (GC) to manage the entire build or to act as your own general contractor by hiring separate trade contractors (also called subcontractors) directly. This decision affects your project cost, timeline, stress level, and the quality of the final product.

Many homeowners are attracted to the idea of hiring separate trades to save the GC's markup, which typically adds 15% to 25% to the project cost. On a $250,000 ADU, that could mean saving $37,500 to $62,500. But as we will explore in this guide, the actual savings are often much smaller than expected, and the risks can be significant.

Understanding the Roles: GC vs. Separate Trades

What a General Contractor Does

A general contractor serves as the single point of responsibility for your entire ADU project. Their responsibilities include project management and scheduling, hiring and supervising all subcontractors, obtaining building permits (for more on this, see verifying permits), material procurement and delivery coordination, quality control and inspection management, budget tracking and financial management, problem-solving and conflict resolution, communication with the homeowner, and compliance with building codes and safety regulations.

What Hiring Separate Trades Means

When you hire separate trades (also called "owner-builder"), you assume the GC role yourself. You directly hire and manage each specialty contractor, including foundation and concrete, framing, roofing, electrical (requires C-10 license), plumbing (requires C-36 license), HVAC (requires C-20 license), insulation, drywall, painting, flooring, cabinet and countertop installation, landscaping, and potentially more.

In California, if you act as your own general contractor, you must either obtain an Owner-Builder permit or hire a licensed GC. The Owner-Builder exemption has specific requirements and limitations under California Business and Professions Code Section 7044.

True Cost Comparison: GC vs. Separate Trades

The potential cost savings from hiring separate trades are often overestimated. Here is a realistic comparison for a typical 800 sq ft detached ADU in Los Angeles.

As this comparison shows, the actual savings from hiring separate trades can be minimal or even negative when you factor in the hidden costs of managing the project yourself. The GC's markup covers real value: their relationships with subcontractors (which often result in lower prices), their project management expertise (which prevents costly delays and mistakes), and their warranty on the overall project.

Pros and Cons of Using a General Contractor

Advantages

• Single point of responsibility: If something goes wrong, you have one person to call. The GC is responsible for coordinating all trades and resolving conflicts.
• Professional project management: GCs manage construction projects for a living. They know how to sequence work, avoid delays, and keep the project moving efficiently.
• Volume pricing on materials and subs: Established GCs have relationships with suppliers and subcontractors that result in better pricing than a one-time buyer can obtain.
• Warranty coverage: The GC typically warrants the entire project, including subcontractor work. This gives you a single warranty claim process rather than dealing with multiple trade contractors.
• Permit and inspection management: The GC handles all permits, scheduling inspections, and resolving any code issues that arise.
• Less stress and time investment: Your primary communication channel is with the GC. You do not need to coordinate with 10 or more separate contractors.

Disadvantages

• Higher cost: The GC's markup (15% to 25%) adds to the overall project cost.
• Less control: You may have less say in which subcontractors are used and how the work is sequenced.
• Communication layer: The GC acts as an intermediary between you and the trade contractors, which can sometimes delay communication or filter information.
• Quality depends on GC selection: A poor GC hire can be worse than managing the project yourself. See our guide on evaluating contractor portfolios for hiring guidance.

Pros and Cons of Hiring Separate Trades

Advantages

• Potential cost savings: Eliminating the GC markup can save money if you are an effective project manager.
• Direct control: You choose every subcontractor and have direct communication with each trade.
• Learning experience: Managing the project yourself gives you deep knowledge of the construction process.
• Flexibility: You can adjust the pace and priorities of the project more easily without going through a GC.

Disadvantages

• Massive time commitment: Expect to invest 200 to 500+ hours managing the project, including evenings and weekends.
• Coordination complexity: You must schedule 10+ different contractors in the correct sequence, managing their availability, inspections, material deliveries, and conflicts.
• No volume discounts: As a one-time buyer, you pay retail prices for materials and market rates for subcontractors.
• Warranty fragmentation: Each trade provides their own warranty (if any). There is no single entity responsible for the overall project.
• Liability risk: As the owner-builder, you assume liability for job site safety, workers' compensation (for any uninsured workers), and building code compliance.
• Knowledge gap: Without construction expertise, you may not recognize quality issues, code violations, or improper sequencing until it is too late.

Who Should Consider Self-Managing with Separate Trades?

Acting as your own GC can work in limited circumstances. Here is who might successfully take this approach:

• Construction professionals: If you work in construction or a closely related field and understand building sequences, codes, and trade coordination.
• Experienced owner-builders: If you have successfully managed a major construction project before.
• Small, simple projects: JADUs or basic garage conversions with minimal scope may be manageable for a hands-on homeowner.
• Strong trade connections: If you have personal relationships with reliable trade contractors who will prioritize your small project.
• Flexible schedule: If you can be available during working hours to manage the job site, receive deliveries, and handle issues as they arise.

The Hybrid Approach: Construction Manager

There is a middle ground between full GC and full self-management: hiring a construction manager (CM) or owner's representative. A CM advises you throughout the project, helps with contractor selection and scheduling, monitors quality and code compliance, and manages the inspection process. The CM's fee is typically 5% to 10% of the construction cost, which is less than a full GC markup but provides professional oversight. This approach works well for homeowners who want more control than a GC arrangement provides but recognize they need professional support.

The Critical ADU Construction Sequence

If you decide to manage separate trades, understanding the correct construction sequence is essential. Here is the typical build order for a detached ADU:

Misordering these phases or failing to schedule inspections between phases is one of the most common and costly mistakes owner-builders make.

Frequently Asked Questions About GC vs. Separate Trades

How much can I really save by hiring separate trades instead of a GC?

The theoretical savings from eliminating the GC markup are 15% to 25% of the construction cost. However, actual savings are typically much less (5% to 10%) due to higher subcontractor prices (no volume discount), scheduling inefficiencies, material procurement at retail prices, and the cost of your time managing the project. Some owner-builders actually spend more than they would have with a GC due to mistakes, rework, and delays.

Do I need a contractor's license to act as my own GC in California?

If you are building an ADU on your own property, you can obtain an Owner-Builder permit without a contractor's license. However, you must sign a notice acknowledging that you are responsible for supervising all work, obtaining inspections, and ensuring code compliance. You also cannot sell the property within one year of completion without disclosing the owner-builder status. Consult the CSLB for specific Owner-Builder requirements.

What insurance do I need if I act as my own GC?

At minimum, you need builder's risk insurance to cover the structure during construction and general liability insurance to cover injuries and property damage on the job site. If any worker you hire directly does not carry their own workers' compensation insurance, you may be liable for workplace injuries. Consult with an insurance broker who specializes in construction coverage.

Can I hire a GC for part of the project and manage the rest myself?

Yes, this hybrid approach is common. For example, you might hire a GC for the structural work (foundation, framing, roofing) and manage the finish work (painting, flooring, fixtures) yourself. This reduces the GC's scope and fee while ensuring the most critical and code-intensive work is professionally managed.

What is the biggest risk of hiring separate trades?

The biggest risk is scheduling gaps and coordination failures. When one trade is delayed, it creates a cascade of delays for every subsequent trade. Professional GCs manage this through relationships, experience, and contractual leverage with their subcontractors. Owner-builders typically have none of these tools and end up with projects that take 30% to 50% longer than they would with a GC.

How do I handle disputes between trade contractors if I am acting as my own GC?

When you are the GC, you are the arbitrator for all disputes between trades. Common disputes include blame-shifting (plumber blames electrician for a problem), scheduling conflicts (two trades need access to the same space), and damage to completed work by subsequent trades. Without construction experience, resolving these disputes fairly and effectively is extremely challenging.

Not sure whether to hire a GC or manage separate trades? Our team can help you evaluate your options and find the right approach for your ADU project.

Decision Matrix: Choosing Between Separate Trades and a General Contractor

To help California homeowners make the right choice for their ADU project, here is a decision matrix that breaks down when each approach makes the most sense based on your project type, experience level, and goals.

When a General Contractor is the Better Choice

• Ground-up new construction ADU: New builds require extensive coordination between foundation, framing, electrical, plumbing, HVAC, roofing, and finish trades. A general contractor manages all of these relationships and schedules inspections at the right times.
• First-time ADU project: If you have never managed a construction project before, a general contractor provides a single point of contact and handles the complexity on your behalf.
• Two-story or complex ADU designs: Projects with structural complexity, engineering requirements, or custom architectural features benefit from a general contractor's experience coordinating specialized trades.
• Tight timeline: General contractors have established relationships with subcontractors and can schedule work more efficiently, reducing delays between phases.
• Full-service garage conversions: Converting a garage to a living space involves structural modifications, utility connections, insulation, and finish work that benefits from coordinated management.

When Hiring Separate Trades Can Work

• Simple cosmetic renovations: If you are updating an existing ADU with new flooring, paint, and fixtures, you can often hire individual tradespeople without needing a general contractor.
• Single-trade projects: Work that primarily involves one specialty, such as upgrading the electrical panel or replumbing a bathroom, can be handled by a single licensed tradesperson.
• Experienced owner-builders: If you have previous construction management experience and understand permit requirements, scheduling, and code compliance, you can save the general contractor's markup by managing trades yourself.
• Budget-constrained projects: Homeowners with more time than money can save 15 to 25 percent by acting as their own project manager, though this comes with significant risk if you lack experience.

For most California homeowners building a new ADU or doing a major conversion, a general contractor is the safer and more efficient choice. The management fee you pay is usually offset by fewer delays, better pricing from subcontractors, and reduced risk of costly mistakes. Learn more about evaluating contractor proposals in our guide to red flags in ADU contractor bids.

Frequently Asked Questions About Hiring Trades vs. a General Contractor

Can I legally act as my own general contractor for an ADU in California?

Yes. California allows homeowners to act as owner-builders on their own property. However, you must file for an Owner-Builder Permit and acknowledge that you are responsible for all code compliance, worker safety, and insurance requirements. As an owner-builder, you cannot hire unlicensed workers for any trade that requires a license, and you must personally supervise all work. If you plan to sell the property within 10 years, you must disclose that the work was done under an owner-builder permit, which some buyers view as a risk factor.

How much do general contractors typically mark up subcontractor costs on ADU projects?

General contractors in California typically add a markup of 15 to 25 percent on top of subcontractor costs. This markup covers project management, scheduling, liability insurance, warranty coverage, and coordination between trades. While this may seem like a significant expense, it often saves money in the long run by preventing costly scheduling conflicts, rework, and code violations that can occur when homeowners manage trades independently. For more on understanding contractor pricing, see our guide on handling ADU change orders.

What happens if one of my individually hired trades causes damage to another trade's work?

When you hire trades separately, you become responsible for resolving disputes between them. If a plumber damages framing work, for example, you must negotiate between the plumbing and framing contractors to determine responsibility and arrange for repairs. With a general contractor, this coordination and dispute resolution is handled for you. This is one of the hidden costs of managing trades independently that homeowners often overlook.

Is it possible to use a hybrid approach with some trades and a partial general contractor?

Some California homeowners use a hybrid approach where they hire a general contractor for the major structural and utility phases (foundation, framing, electrical, plumbing) and then manage finish trades like painting, flooring, and landscaping themselves. This can work well if you have the time and basic project management skills. Discuss this option with potential general contractors upfront, as not all are willing to take on partial-scope projects. Make sure your ADU contract clearly defines the scope boundaries.