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What will this project cost?

What is this ADU going to cost, and can I afford it is one of the biggest questions a homeowner faces when taking on a potential construction and/or renovation project. In this post, we'll explore the best strategy for making sure your new dwelling unit is one you can afford!

To start, some jurisdictions have created ADU pricing calculators to help you get a sense of the potential costs to build. These tools are designed to help provide a very rough estimate of the costs to build an ADU based on information such as the size of the unit, whether you are building a new unit or converting an existing structure, and many of these tools also build in an assessment on the cost for permitting the unit. These tools are designed to help you get a very general sense of the potential costs early in the decision-making process and ideally before you start to spend money on design or other professionals. (See links to some sample calculators below).

Determining the cost of building an ADU depends on various factors, including specific site conditions on your property that may influence the type of foundation required, the removal of existing natural or man-made structures, the size and location of utility connections for the new unit, and the desired finishes such as lighting, tile work, flooring, and cabinetry. To accurately assess the cost of constructing an ADU or JADU on your property, it is advisable to engage an architect or design professional who can tailor the project to your specific needs, preferences, and property requirements.

Typically, the process involves having your architect design the unit, and once the plans are finalized, you can obtain estimates from builders for the construction costs. However, if the estimates exceed your budget, you may need to collaborate with your architect to revise the plans and reduce costs. However, plan revisions can be expensive. Alternatively, you can involve a potential general contractor (GC) in the early stages of the design process. By doing so, the GC can suggest cost-saving alternatives, such as consolidating plumbing in one area, recommending energy-efficient utility systems and construction methods, or proposing more economical products and finishes. This process is commonly known as "cost engineering" in the industry. This strategy also helps you get more familiar with the GC, how they communicate, and their level of interest in your potential project before going into a binding contract.

The question arises: when is the right time to involve a potential GC in the process? The design process typically consists of several phases. The initial phase, called schematic design, involves determining the basic layout of the space, including exterior and interior walls, room sizes and locations, door and window placements, exterior elevations, and roof design. During this phase, you can obtain a comprehensive estimate from a GC to get a realistic understanding of the costs before the architect completes the full permitting and construction plans or involves engineers. When sharing the schematic design with potential GCs, it is advisable to provide them with any due diligence reports you have obtained, such as soils reports or sewer lateral inspection reports, which identify any issues that may affect the foundation or utility connections.

After reviewing this information and conducting a site visit to assess existing conditions and utility hookups, the GC should be able to provide you with a detailed estimate for the project. Once you have met with the GC and reviewed the initial schematic design and cost estimate, you can provide feedback to your architect or designer before finalizing the permit and construction plans.

Once the architect or design professional completes the final set of plans, along with any necessary civil, structural, and landscape plans (if needed), you can request final estimates or bids from the GC you have been working with, as well as other potential GC's, for your review and consideration. The more detailed information the GC has about your desired finishes, the more accurate the bid will be.

Determining the true price of your potential ADU project requires an investment of time and financial resources. It is advisable to gather information about the general costs of ADUs early on, using online tools as a starting point. Hiring Hello Housing’s ADU team of experts to help you navigate this process can be another great step in avoiding costly mistakes and getting the best possible outcome.

We are here to help no matter where you are in your process.


The HelloADU Team

Sample Calculator Tools:


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