ADU Floor Plans for Washington Homeowners
Add a backyard home for family, rental income or a home office. Factory-built ADUs arrive finished, so there is less time under construction on your property.
A Faster, More Predictable Way to Add a Second Home
An accessory dwelling unit (ADU) is a small, separate home on the same lot as your main house. Because the home is built indoors at the factory, the schedule is more predictable and the price is known before you order, which is hard to say about most site-built construction.
James Wonser is a trained ADU specialist and a licensed Realtor with lot development experience. That means one person can help you judge whether your lot works, which size makes sense, and what an ADU could do for your property value or rental income.
Washington has been opening the door to ADUs. A 2023 state law (HB 1337) requires most cities in urban growth areas to allow them, but permit rules, size limits and utility requirements still vary by city and county, so we check yours before you order.
Compact Floor Plans
Single-section and small multi-section plans from the factory sized for backyards and narrow lots.
Finished at the Factory
Kitchen, bath, flooring and finishes arrive installed. Site work happens while the home is being built.
Rental or Family Use
Use it for a parent, an adult child, a long-term rental or a studio.
Permit & Zoning Guidance
We help you find out what your city or county allows before you commit.
Financing Options
We work with lenders familiar with manufactured and ADU projects.
What to Decide Before You Choose a Floor Plan
Lot & Setbacks
Your lot size, setbacks and access for delivery decide which plans fit. Crane or tight-access setups can change the site cost.
Size & Layout
Studios and one-bedrooms suit rentals and guests. Two-bedroom plans work better for family members living full time.
Utilities
Water, sewer or septic, and electrical service all need to be connected. Capacity on your existing system matters.
Foundation
Foundation type affects permitting and financing. Many lenders require a permanent foundation.
Local Rules
Owner occupancy, size caps, parking and design standards are set locally and can change.
Budget
Plan for the home, delivery, setup, foundation, utilities and permits together, not the home price alone.
From First Call to Move-In
Review Your Lot
We look at size, access, utilities and local ADU rules for your address.
Pick a Floor Plan
Choose from compact factory plans that fit your lot and your goal.
Permits & Site Prep
Your licensed contractors prepare the site and pull permits while the factory builds.
Delivery & Setup
The home is delivered, set, hooked up and ready for final inspection.
Frequently Asked Questions
Can a manufactured home be used as an ADU in Washington?+
In many jurisdictions, yes. Rules vary by city and county, including foundation, size and design requirements, so we check your local code before you order.
How big can an ADU be?+
Size limits are set locally. Many jurisdictions cap detached ADUs by square footage or as a percentage of the main home, so confirm with your planning department. We can help with that.
How long does it take to get an ADU?+
A factory build takes about 12 weeks, and delivery and setup usually add 30 to 60 days. Permitting time depends on your city or county and can run in parallel.
Can I rent out my ADU?+
Usually yes, but some places have rules on short-term rentals or owner occupancy. Check your local requirements before you plan around rental income.
Do I need a permanent foundation?+
Often, and many lenders require one. The requirement depends on your jurisdiction and financing. Concrete slabs are required for land financing and must meet or exceed state standards.
How do I get a price?+
Contact us with your address and what you want to use the ADU for. We will recommend floor plans and send wholesale pricing.
Thinking About an ADU on Your Property?
Send us your address and goals. We will tell you what looks possible and what it could cost.
Toledo: 202 Drews Prairie Rd, Toledo, WA 98591 Â |Â Longview: 1322 Commerce Ave, Suite #210, Longview, WA 98632