Frequently Asked Questions about ADU Design and Construction
We understand that there are many considerations during the process of planning an Accessory Dwelling Unit. Below are some frequently asked questions about designing and building an ADU.
Question 1: How much does it cost to build an ADU?
This is difficult to answer without the specifics of a project but we can at least give you some insight into typical costs of a new construction, detached ADU in SF Bay Area, California.
Construction $225,000 to $350,000+
Design $17,000 to $30,000
Permits $6,000 to $23,000
The range in permit cost is largely dependent on two things:
Is the ADU being built initially as a short term rental?
Do the additional plumbing fixtures for the ADU necessitate a new water supply branch installation by Water Agency?
TOTAL PROJECT COST - $248,000 to $403,000
This is a rough breakdown and the specifics of each site, the building conditions, the final design, the availability of contractors and materials, among many other factors can affect the final costs of the project. Our design fees vary by project based on site, complexity, historic design review, permitting requirements, etc. We usually work for a lump-sum fee to allow our clients to have cost certainty while breaking the fee into monthly payments based on work performed.
Question 2: How long does it take to design and build an Accessory Dwelling Unit?
2 to 3.5 months to design
2 to 3.5 months to get permit approval
6 to 9 months to build depending on weather & contractor
TOTAL DURATION - 10 to16 Months
Question 3: What services do architects provide?
Our role as the architect is to see the big picture when it comes to your project, and following that concept through to the details, resulting in a thoughtful and beautiful project. We will help you explore what appeals to you aesthetically and what you require functionally. We work to coordinate the team of design, engineering and construction professionals towards this common goal. In short, we follow your project from early concept design through completed construction working with your best interests at heart.
Question 4: What's my role in the design process?
We will depend on you to communicate your design preferences, functional requirements, and budget. Your input to questions and our design deliverables during the process will help keep the project on track.
Question 5: WHERE CAN I SAVE COST IN CONSTRUCTION?
For ADUs, if you don’t want to provide cooling to save cost, here are a couple ways to comply with title 24 with space heating and domestic hot water?
In lighter energy load scenario with small space 240-300SF
Electrical Wall Panel Heater -
Tankless Hot Water Heater- Gas is allowed if you are not building new.
In medium energy load with medium size space 300-450 SF
Radiant Floor Heating – Heating only
Heat Pump Hot Water Heater – For Domestic Water.
In larger energy load with larger space, 450 SF or above.
Mini Split system - Heating and Cooling is bonus
Heat Pump Hot Water Heater – For Domestic Water.