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ADU Professionals to Hire for Your Team

Author: Scott Johnson, ADU Expert @ Napa Sonoma ADU Center & Founder, Pocket Housing LLC

Throughout your ADU journey, you will find yourself in need of professional services to help you complete your ADU project. This post offers a brief description of the most common professions involved with building an ADU, listed in rough order of their involvement in a project. 

Depending on the specifics of your project, you may or may not need all of the professionals listed here. As we’ve said before, costs can vary widely depending on the choices you make early in the design process. This also applies to who you chose as part of your team. It is worth your time and energy to get multiple bids and compare the scopes of work. However, the cheapest bid is not always the best choice in the long run. 

Professionals with ADU experience are key to a smooth, cost-effective project. Since ADUs are currently growing in popularity, it may be hard to find a professional with ADU experience. If that’s the case, then communicate early on with your professional team to ensure they are aware of the most current local ADU rules in your jurisdiction. As a starting point, you can find a Vendor Registry on our website right here — and we are adding to it all the time!

With that, here’s a list of some of the types of professionals you may need for your ADU project, in roughly the order you’d most likely need them over the course of the project:

Project Manager

While an ADU is physically smaller than building a house, it is almost as complex and time consuming. Some homeowners hire a project manager to ensure the project is completed in a timely manner, and without significant setbacks. Project managers can be part of a design/build firm, a general contractor, or an independent contractor. Other homeowners may choose to manage the project themselves, although this can be a tough task if you’re not familiar with construction projects. See our ADU Workbook on pages 3 and page 80 for more details.

Geotechnical Engineer/Soils Engineer

The Geotechnical Engineer is a Civil Engineer who samples the soil where the ADU will be located and creates a report that describes in technical detail the types and qualities of soils found on site. Not all jurisdictions require a soils report, but where they are required, they are critical. Some jurisdictions allow you to submit a waiver form for the soils report, but this waiver form often requires that you hire and pay an engineer to complete it. It is recommended that the Geotechnical Engineer is contracted directly with you, the homeowner and not through an architect, designer, project manager or design/build firm.

Architect/Designer 

In the state of California, a licensed architect is not required to design a single residence, such as an ADU. However, it is important to hire someone with the professional experience and insurance to design your project — whether this be a designer or a licensed architect. See more details in our ADU Workbook at page 43.

Civil Engineer 

Civil Engineers generally deal with the land your ADU will rest on. If your site needs to be flattened, or has drainage issues, or needs retaining walls, a Civil Engineer is the professional that will help solve those issues. For properties on well/septic systems, a Civil Engineer may be needed to prove that you will have enough water/sewer capacity for the ADU you want to build. They can also provide or oversee surveying services should you need to confirm your property lines.

Structural Engineer

Structural Engineers work hand-in-hand with your designer/architect to ensure that the structure being designed is built strong enough and to code. In many cases, the architect or designer will get structural engineer bids for you and manage the relationship. If you are managing the project yourself, you can use initial project ‘sketches’ from your designer to solicit bids from engineers. They often use the soils report to specify the type and size of foundation footings, bracing and nailing schedules for framing, among other critical tasks.

General Contractor 

The general contractor is responsible for the actual construction of your ADU. There are many types of general contractors. Some are large companies that keep all the specialties, such as plumbing or electrical, in-house. They can also be solo individuals that will sub-contract the specialty work out to other companies. Regardless of their size or structure, the general contractor is ultimately responsible for any work performed. Check out our ADU Workbook at page 85 for guidance on hiring a contractor.

Design/Build 

A design/build firm is typically a combination of professionals that can provide start to finish service: From initial assessment and design, through permitting and construction. The benefit of a design/build firm is that it is one team from start to finish. Check out our ADU Workbook at page 85 for guidance on hiring a contractor.

Title 24/CalGreen Energy Consultant

A Title 24/CalGreen Energy consultant is a specialist who analyzes architectural plans to ensure they comply with Title 24, the code section that deals with energy efficiency, and CalGreen, the “green building code.” Typically, the designer/architect will handle the relationship with the Title 24/CalGreen consultant. There may be 1 or 2 rounds of finessing the design to make it comply before it can be submitted to the jurisdiction for approval. Check out our ADU Workbook at page 66 for more information on Title 24.

Fire Sprinkler System Designer 

Should your project require sprinklers, a fire sprinkler system designer will often be employed to design the system and ensure it complies with current fire code. Much like the Title 24/Calgreen consultant, the system designer will often be managed by the designer/architect. Whether or not your project will require fire sprinklers will be largely dependent on your specific project and the requirements of your local Fire Department, although local fire departments are governed by state law on this matter. It is important to find out upfront at the beginning of your project whether you’ll need to add fire sprinklers, as they can be a significant extra cost to install.

Historic Resource Professional 

If your house is located within a historic district, it may be necessary to commission a report from a historic resource professional. These reports typically review the historic context of your house and proposed ADU and provide design recommendations to ensure that your ADU is harmonious with the historic district.

Arborist

If you have large, potentially significant trees in the area of your proposed ADU it is wise to consult an arborist to receive advice on how to ensure that the trees and the root systems aren’t damaged by constructing your project. If your local jurisdiction has a tree protection ordinance, you may be required to submit an arborist’s report detailing the type, size and location of existing trees that may be impacted by construction.

Licensed Surveyor 

If your proposed ADU is near any of the setback limits it can be wise to have at least a partial survey of your property completed to ensure that the location of your ADU does not fall within any restricted setbacks. Existing fence lines are not always an accurate representation of property lines.

Solar System Professional 

If you are planning a detached ADU, then you’ll need to discuss your plans with a solar system designer/engineer. They will be able to design and specify a solar array that meets the code requirements. They will also likely coordinate with your designer and general contractor to ensure that the whole electrical system is designed as one cohesive element.


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