Adding an Accessory Dwelling Unit (ADU) or Detached Accessory Dwelling Unit (DADU) to Your Property
Adding an Accessory Dwelling Unit (ADU) or Detached Accessory Dwelling Unit (DADU) to your property is an excellent way to increase living space, generate rental income, or accommodate family. When you’re ready to build, one of the first big decisions is whether to create a customized or personalized pre-approved DADU plan. Understanding the difference between these two options will help you make the best choice for your budget, timeline, and vision.

Fully Custom DADU Designs: Tailored to Your Exact Needs
For homeowners who want a truly one-of-a-kind space, a fully custom DADU provides the ultimate flexibility. A custom-designed unit gives you control over every detail, including the floor plan, room sizes, window placements, and interior finishes. This personalized approach ensures the DADU aligns perfectly with your lifestyle, whether you want an open-concept studio, a multi-bedroom family space, or a home office retreat.
The biggest advantage of a custom design is the ability to optimize every inch of the space. You can incorporate specific design elements, eco-friendly features, or architectural styles that perfectly reflect your personality. While this approach often requires more time and a larger investment, the result is a unique structure that fits your exact needs and aesthetic preferences.
Personalized Pre-Approved DADU Plans: A Faster, Smarter Option
If your top priorities are time and budget, a pre-approved template plan might be the ideal solution. These plans are pre-designed layouts that have already been reviewed and approved by the city of Seattle, meeting all local building codes and zoning requirements. Using a pre-approved plan drastically reduces the architectural design time and the hassle of navigating a lengthy review process. This streamlined approach allows you to move quickly from planning to construction, saving you both time and money.
While they are standardized, many pre-approved plans offer options for personalization. You can often choose from a variety of cosmetic fixtures, interior finishes, exterior siding, and color schemes to customize the look and feel of your DADU. This allows you to maintain a cohesive aesthetic with your main home while still adding your own unique touch, creating a space that is both functional and personal.
Making the Right Choice for Your Project
The decision between a fully custom DADU design and a pre-approved plan comes down to your individual priorities, timeline, and budget. If you want a highly personalized space and have flexibility in your schedule, a custom design is the perfect fit. On the other hand, if you want to build quickly and keep costs manageable, a personalized pre-approved plan with customizable features is a smart choice.
At Tenhulzen Construction, we have extensive experience helping clients with both options. We can guide you through the process of developing a fully custom DADU or help you select and customize a pre-approved plan for a faster, more cost-effective project.
Ready to start planning your DADU? Contact us today to discuss your ideas and discover the best path forward to create a space that’s perfect for you.