Prefab and Custom-Designed ADU Solutions.
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Your Vision, Realized
Seattle ADU Contractors
Haas Development & Construction is proud to offer the Greater Seattle area services to build ADUs, configured for your unique property — either attached (AADU) or detached (DADU) from your home. Our team is dedicated to designing and constructing your ADU unit with your primary goal in mind and can customize the build to meet your individual needs.
What is an ADU?
Accessory dwelling units (ADU), and detached accessory dwelling units (DADU), are secondary housing units on a single-family residence lot. The City of Seattle allows most homeowners to build two ADUs on the same property as their home. Homeowners can combine different ADU types depending on the size and shape of their property:
- Both ADUs can be attached or internal to the existing living space (AADUs).
- There can be one AADU and one detached ADU (DADU).
An ADU is not just an opportunity to increase the value of your property. It’s an opportunity to get the most out of your home — supporting your family’s longevity in a single place or offering new financial freedoms.
ADU/DADU Services
Our team offers a range of services to get you started on your Seattle ADU including:
- ADU/DADU Planning
- DADU Pre-approved Plans
- ADU/DADU Custom Design & Engineering
- ADU/DADU Builds
Thinking of building an ADU? The ADU contractors at Haas have the expertise to walk you through every step of this process. Whether you’re in the beginning stages or need advice on an existing project, our team is ready to join your project.
Check out our collection of past projects or give us a call at 206.494.3369 to learn more.
The Haas Process
From Planning to Move-in Day
03.
Custom ADU solutions
Select a design package and customize it to suit your needs.
04.
The Build
Turn your plans into reality. Time for Haas to build your cottage to whatever level of finish and completion you desire.
05.
Move-in Ready
With our end-to-end ADU/DADU services, you can trust us to bring your vision to life with precision, speed and unparalleled craftsmanship.
Design Your ADU Solution
At Haas, we offer DADU pre-approved prefab plans and a range of services for custom ADU/DADU builds. Our team works with you to plan to deliver the appropriate planning and solution for your property.
DADU Prefab Plans and Packages
- Pre-approved by the City of Seattle
- Tailored to your needs
- Time-saving, cost-effective
Custom ADU/DADU Builds
- Planning and permitting assistance
- Expert design and engineering
- Fully custom ADU/DADUs
