6 構建
PERMIT IN HAND, YOU’RE READY TO BREAK GROUND and see your project become a reality! From site preparation to passing your final inspection, you’ll stay in touch with your contractor and make final decisions about project details.
時間軸
The Construction process typically takes 6-12 months. Most ADU projects take 12-18 months to complete, but some extend to 24 months or more.
常見問題
Here are a few of the most frequently asked questions about ADU construction. See the content below and our ADU Guidebook for more guidance, resources, and tips for all steps of the process.
附屬住宅單元的建造成本將根據個人喜好、場地條件、位置和許多其他因素而有很大差異。儘管許多人認為如此，較小的 ADU 的成本可能與較大的 ADU 幾乎相同。對於較大的 ADU，許多成本（例如地基、廚房和浴室工程）僅略有增加。廚房費用為 25,000 美元至 50,000 美元，每間浴室費用為 15,000 美元至 25,000 美元。
類型：新建的建築，無論是獨立式或連體式，往往是最昂貴的。車庫改建並不比新車庫便宜多少。室內空間（地下室或其他）的改造通常是最便宜的。
其他因素：
- 室內裝潢工程和設施的品質
- 建築形式和細節
- 所需的公用設施、結構、機械、電氣和管道升級程度
- 所需場地升級（人行道、下水道和供水）
- 是否需要灑水裝置
- 門窗是否符合緊急出口標準
- 地塊複雜性（坡度、樹木、斷層線等）
傳統施工需要 6 至 12 個月，但這會根據專案的具體情況而有所不同。施工階段包括：
- 場地準備：1-2個月
- 基礎：1個月
- 牆壁、屋頂、門：1-2個月
- 管道和電氣：1-2個月
- 隔熱乾牆： ½-1 個月
- 固定裝置和飾面：1-2個月
- 最後潤飾：½-2 個月
雖然您的承包商將領導施工過程，但您將承擔以下責任：
- 與您的承包商保持聯繫並製定入住時間表。
- 定期巡視施工區域以監控工作品質並確保工作以您預期的方式進行。
- 準備好及時就細節（燈具、電器和其他材料）做出決定，以便您的承包商能夠按計劃進行。
- 遵守您同意的合同，包括變更單中具體描述的任何變更。
- 儘管您的承包商通常會安排所需的城市或公用設施檢查，但作為業主，您有責任確保按要求進行檢查。
現場建造/傳統：傳統建造的 ADU 是專門根據您的喜好和財產設計和建造的，並在現場建造（“現場建造”）。此選項允許在整個建置過程中進行大量自訂和較小的更改。
預製/面板化/模組化：這些 ADU 部分或大部分在工廠建造，然後運送到您的現場進行組裝。有時，公司會在其費用中包含所有服務（「交鑰匙」），包括許可方面的幫助和所有現場施工任務（例如，奠定基礎、公用設施連接等）。其他時候，您需要聘請額外的專業人員來提供協助。
逐步
Building Your ADU
記住：
Often, people who are their own general contractors have a difficult time. Building an ADU is more like building an entire home than a renovation. If you’re working with a design/build team or have hired a general contractor, they’ll manage the project (including contract negotiation, payment schedules, quality checks, and working with your City and other agencies).
While it may cost more up front, you might save a lot of money by reducing delays or change orders, and get your ADU rented sooner too.
Hire your contractor
If you are not using a design/build firm, you will need to hire a contractor for the construction phase of your ADU. You will use drawings from your designer to get bids from contractors and make sure you are specific about what you want each bid to include (license details, insurance information, examples of past work, etc.). Your design team may be able to help you with this.
It’s a good idea to select between at least three bids, and it’s okay to ask contractors clarifying questions about their bid. Your designer may be able to help you compare the bids. It’s a good idea to reach out to references and to consider your personal interactions with the contractor – you’ll want to feel like you work well together and that they understand your goals.
See our Guidebook for many more details on getting bids and hiring a contractor.
有用的工具
Monitor construction
Once you have building permits, the contractor you hire will lead the construction of your ADU. Be sure you have all funding in place before you start construction.
Communicate frequently with your contractor to make decisions about fixtures and finishes as needed and verify progress before making payments. Timelines for construction vary, but 6-12 months is fairly common. See more details about managing construction in our Guidebook.
Get inspections
During construction, your ADU will be inspected multiple times to ensure it is being built according to the permitted plans (typical inspections include foundations/footings, framing, electrical/plumbing, and exterior finishes).
Many cities have online portals or direct phone numbers for scheduling inspections. Generally, it is your and your contractor’s responsibility to schedule all required inspections. For a list of inspections and how to schedule, contact your Building Department. After your final inspection is approved, some cities will issue a certificate of occupancy. Your ADU is ready for move-in!
COnstruction Costs
ADU construction costs vary significantly depending on materials, site conditions, location, and other factors.
The cost to build an ADU typically ranges from $30,000 for a simple interior conversion JADU, to $400,000+ for a large detached ADU with high-end finishes on a hillside lot. Cost per square foot is a good way to estimate, though this too can range from $150-500 per square foot per square foot depending on the complexity and finishes of your project. A good starting estimate of construction costs is $350-450 per square foot for an average project (with $400-$550 per square foot per square foot as a good starting estimate for total costs, including design, permitting and construction).
Despite what many think, smaller ADUs may cost almost the same as larger ones because construction costs are not related to size. Many costs like foundation, kitchen and bathroom work only increase slightly for larger ADUs. Kitchen costs will range from $25,000–$50,000 with each bathroom ranging from $15,000–$25,000.
Visit our Stories to see real-world cost examples for ADUs built in Santa Clara County.
