Frequently Asked Questions about ADU Design and Construction

We understand that the process of building an Accessory Dwelling Unit can be confusing and stressful. Below are some frequently asked questions about designing and building an ADU and hiring an architect.

Question 1: How much does it cost to build an ADU?

One of the first questions we always get asked is how much a project costs and what our design fee is. This is a difficult question to answer without knowing more about the specifics of your project but we can at least give you some insight into the typical construction cost of a new construction, detached ADU in Portland, Oregon. Note, the numbers below are just a rough estimate and can vary greatly depending on the site, size, design, and final materials and finishes. 

  • $175,000 to $250,000 or higher - Construction costs with a General Contractor

  • $15,000 to $30,000 - Architectural fees (8-12% of construction costs)

  • $2,000 to $3,000 - structural engineering fees

  • $6,000 to $12,000 - Permits (most of Portland's System Development Charges (SDC) fees are waived until the summer of 2018, saving up to $12,000 and making it a perfect time to move ahead with your project)

  • $198,000 to $295,000 - ESTIMATED TOTAL PROJECT COST

Of course, this is just 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 dramatically alter the final costs of the project. Also, the quality of finish materials, appliances, fixtures and other design elements can impact this cost. Please use these numbers as a rough estimate as you learn more about the ADU process and start budgeting for your project.

Location also plays a big role in the cost of the project. Labor and materials prices can vary dramatically across the country. We are familiar with the costs of building ADUs in Portland and around Oregon, but would need to do more research on your area to give a more accurate estimate. Finally, our design fees vary by project based on site, complexity, historic design review, permitting requirements, etc. We usually work for a lump-sum fee and break our design fee down into even monthly payments, allowing our clients to have cost certainty and predictable invoices. 

Question 2: How long does it take to design and build an Accessory Dwelling Unit?

This is another tough one to answer as every project and client is different. In our experience it can take about 10-15 weeks to design an ADU, about 8-10 weeks to get permit approval from the City of Portland, and another 4 to 8 months to build depending on weather, unexpected delays and other unforeseen setbacks. In total that comes out to 9-months to a year, although we would recommend planning for a full year from start to finish.

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 bring that concept through to the intimate details. We will help you explore what appeals to you aesthetically and what you require functionally. We will coordinate the team of design, engineering and construction professionals. We will also guide your project through the maze of building codes and zoning requirements. Our job is to work with you and all of the other people involved, so that your project is built the way it was intended, and that the final project meets your needs. We can help you with everything from creating a site plan, developing the architectural concept and floor plans, all the way to selecting tiles, counters, and other finish materials. In short, we follow your project from early concept design through completed construction working with your best interests at heart.

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Question 4: At what point in my project should I involve an architect?

As soon as you decide you want to build something new or renovate a space you already have, you should start looking for an architect. Architects provide important pre-design services including site evaluation, feasibility studies, programming, and can help you explore options you may not have considered. Involving an architect early in the process can help avoid costly mistakes, and increase the likelihood of your satisfaction with the project.

Question 5: Don't architects add substantial cost to a project?

Although architects' fees are a project cost, hiring an architect can actually save you money in many ways. We can monitor your budget and negotiate to get the best materials and workmanship at a good price. Our designs can reduce energy, water, maintenance and lifecycle costs. We can turn a difficult lot into a successful building site. We also spend time planning and fully developing your ideas to hopefully avoid costly changes once construction is underway - one of the biggest reasons projects can go over budget and schedule is changes in the field. It is always easier and cheaper to make edits on paper before construction begins. We can also work within your budget, meaning architectural fees don't have to increase the total cost of the project, as we know that budgets are always limited. 

Question 6: How are architects compensated?

Our fees can be based on time, a stipulated lump sum, a percentage of the construction cost or the project's square footage. We are open to various forms of compensation to best fit the specifics of the project and the client. However, our most common fee structure is a lump sum fee. We find that clients like to have cost certainty when it comes to the design fees. 

Question 7: What's my role in the design process?

We will depend on you to communicate your design preferences, functional requirements, and budget. Your timely response to questions and design submissions will help keep the project on schedule. It is also important for you to raise any concerns you have as the project proceeds, so they can be addressed in the earliest stages. Working in partnership with us will help ensure the best possible outcome for your project.

Question 8: Do I need an architect for my project?

Architects are required for most commercial buildings and projects over a certain square footage. Although many residential projects don't specifically require an architect, the value that an architect brings to a project can't be overstated. Architects act as a client representative, working for you so each project is designed and built with integrity. We bring years of design experience to each project.

If you have any further questions don't hesitate to give us a call or fill out the contact form below. We will do our best to get back to you as soon as possible. Thanks.