ADU & DADU: Additional Dwelling Units & Detached Accessory Dwelling Units

Fully Personalized & Pre-Approved Plans

Washington State’s House Bill 1337 significantly impacts how all cities and counties plan under the Growth Management Act (GMA) that regulate Accessory Dwelling Units (ADUs), including Detached Accessory Dwelling Units (DADUs). Discover your pre-approved and personalized options with Tenhulzen Construction.

Streamlined Regulations Provide Options

Recent changes in Washington State significantly impact how cities and counties under the Growth Management Act (GMA) regulate ADUs, including DADUs. These changes primarily benefit homeowners by improving affordability and flexibility while reducing the construction timeline.

Choose pre-approved plans for a quicker, more affordable build. For greater design freedom, opt for custom plans, which involve more planning and a longer permitting process.

Benefits of Pre-Approved ADU/DADU Plans

Pre-approved plans for ADUs and DADUs offer significant benefits, including faster and easier permitting, leading to quicker construction start times and potential cost savings by eliminating the need for a separate custom design process.

These streamlined processes provide more certainty and predictability, making the entire development experience less stressful for homeowners. The pre-approved plans are already vetted for compliance with Seattle’s codes and standards, simplifying the path to obtaining a permit. Reach out today to see if your property is eligible.

Rendering by CAST Architecture

Fully Customizable ADU and DADU Options

Customizable ADUs/DADUs, designed with architects and interior designers, can perfectly match your home and style. Ideal for flexible timelines, this option offers tailored design to your exact specifications, lifestyle, and aesthetic. We’ll bring your dream ADU to life, increasing property value and complementing your existing home.

One-Story, Two-Story, or Studio

Choose from over 160 pre-approved plans for your streamlined ADU/DADU project in Seattle. If your property is located outside Seattle, a template plan can still help you save significant time and money on architectural design.

Personalize your Pre-Approval

Personalizing your pre-approved plans by selecting design elements and colors provides an exciting opportunity to express your unique style within a structured framework. This customization process lets you choose from various architectural styles, materials, and finishes, ensuring that your vision shines through in every detail.

Completely Customized Complementary Unit

Customizing your DADU to match your primary residence offers several benefits. It creates a cohesive aesthetic that enhances your property’s appeal and contributes to a harmonious neighborhood. This visual continuity can increase property value, as buyers often prefer homes with consistent design. A tailored DADU can meet specific needs—such as hosting guests or generating rental income—making it both functional and stylish.

Hear From Our Past Clients

Hear from satisfied homeowners who have trusted Tenhulzen to bring their dream kitchens to life. Our reputation for quality and creativity speaks for itself.

FAQs About ADUs and DADUs

What is the difference between attached and detached ADUs?

An attached ADU shares one or more walls with the main house, making it ideal for family members or caregivers. A detached ADU is a separate building on your property, often suited for passive income or rental purposes, offering more privacy but typically at a higher cost.

How do city and county regulations impact building an ADU?

Regulations vary by locality. In Washington, some areas allow one attached and one detached ADU per lot, provided there’s enough space and compliance with setback requirements. Certainty cities like Seattle and Kirkland have even more favorable regulations.

What are the benefits of hiring a professional designer or remodeler for my ADU?

Working with an experienced design-build remodeler familiar with local codes helps ensure your plans meet all permitting laws. This can save significant time and money by avoiding costly redesigns and delays associated with off-the-shelf plans or kits.

How does building an ADU affect my home’s value and ROI?

Adding an ADU can increase your property’s value by up to 35%, according to Realtor magazine. Detached ADUs are more expensive but can generate passive income and privacy, with the potential for a return on investment that exceeds 80%.

Ready to Get Started?

Washington’s new streamlined regulations and our library of pre-approved plans make it easier than ever to bring your vision to life. Whether you want a fast-track project with a pre-approved design or a fully customized unit tailored to your lifestyle, we’re here to guide you through every step of the process.

Let’s turn your property into more living space, rental income, or a flexible family solution.