DADU’s are a great way for a city to add density and diversity to the housing stock and can offer greater flexibility to any homeowner. So why haven’t we scene more DADU’s being built? We will cover 3 factors that can help someone who might be interested in building one navigate the process.

Cost

$350 per square foot is a great ‘at home’ budget number to start with. Based on our experience, here is how that cost might break down.

The Washington State average construction cost is $309 per square foot while the Seattle Metro average is a bit higher at $325. These numbers represent the cost of materials, labor, site work, etc. While material and labor costs fluctuate year after year, working with the right architect and contractor can help realize the budget alongside the design.

Think of design fees as a bucket for the architect and all necessary consultants, structural engineers, surveyor, special reports, etc. The design fees will add anywhere from $15-$30 per square foot to the total costs depending on certain design factors like site constraints, program requirements, and design intent . You can work directly with an Architect to receive a more accurate budget based on your project needs.

The last piece to consider are permit costs. The city of Seattle provides a useful estimating tool, HERE, to help plan and budget for permitting fees. Simply, enter your desired square footage into the “R3,VB” row and scroll down.

Design

Design is what transforms a generic structure into a space that feels intentional, something that really fits your lot, your goals, and your life. Every build will have unforeseen challenges but having the right partner to help guide your project through them can make all the difference.

Is the project over budget? It starts with scale. While 900 square feet might sound right at first, the design process might reveal that 600 square feet could do the job better and save a meaningful amount in construction costs.

Not sure about how long permitting will take? The right partner can help keep things on schedule. We spend a lot of time upfront navigating the zoning and permitting process. Every site is different, but it helps to work with someone diligent who can flag potential constraints early and hep you move through the process with minimal surprises.

Is the contractor adding costly changes to the build during construction? A clear and well-documented set of construction drawings can help avoid guesswork in the field. These drawings are also required for permitting, and detailed documents tend to move through the city more quickly.

A thoughtful design keeps the project on track, supports your budget, and helps the finished space feel like it belongs there.

Value

A DADU is more than just a rental property or a building that takes up space in the back yard, it’s an investment that will serve you and your family for decades to come.

• Rental Income: Monthly rents in Seattle typically range form $1,500 to $2,500 depending on the neighborhood location, finish level, and layout.
• Property Value: A thoughtfully designed DADU can increase your principal homes resale value by 10-25%.
• Flexibility: Whether it becomes a home for aging parents, a place for a guest or tenant, a quiet office with a garden view, a DADU adapts to you, it grows and ages with you, it can change and be re-imagined over time.

Final Thoughts

DADU’s are a great way to increase density and rental opportunities in our cities beyond the grasp of corporations. They represent a lot of things like monetary gains, lifestyle flexibility, and neighborhood longevity. We know how significant an undertaking the design and construction can be, hopefully this entry helps to clear an initial path forward and make the finish line a bit easier to see.

We are here to help to build a better world, build better cities, and build better neighborhoods; for us, for our kids, for our future.