Modern house with a flat roof, large front window, and wooden accent panels, surrounded by green trees and a well-manicured lawn.

A thoughtfully designed ADU, built for your lifestyle.

Explore the ADU Series
Modern glass house at sunset with interior living space, kitchen, bedroom, and outdoor patio area.
Modern two-story house with a flat roof, large windows, and a mix of white and wooden exterior design, illuminated from inside at dusk.

Each ADU is designed around light, proportion, and real site constraints.

Small modern house with white siding, black window frames, a white door, and a small set of stairs leading to the entrance, surrounded by a green lawn and trees.
Modern residential house with a curved black roof, white walls, and wooden slats on the exterior. There are neatly trimmed bushes along the front and a concrete driveway with a white car parked.

Once the design intent is clear, the project is fully permitted and built by Emerald State Contracting LLC, a licensed Washington contractor.

Seattle • Bellevue • Eastside
•Site Specific Planning

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Modern tiny house with white and wooden exterior, large windows, and a small porch, surrounded by plants and trees, with a white dog lying on the porch.
Get A Site Specific Price Range

Modern, site-built backyard homes designed for Northwest living.

At Emerald State Contracting, we specialize in designing and building high-quality ADUs and DADUs across Seattle, Bellevue, Renton, Tacoma, and surrounding communities. Whether you’re creating space for family, adding a rental unit, or investing in your property long term, we help you build a modern backyard home that fits your lifestyle, budget, and lot conditions.

Unlike prefab structures, our ADUs are fully site built with long lasting materials, proper foundations, full utility connections, and custom finishes. Every project is engineered, permitted, and constructed to meet (and often exceed) Washington building codes.

Modern bedroom with large glass windows showing a garden with trees and shrubs, a bed with white bedding, and wooden furniture including shelves and cabinetry, illuminated with warm strip lighting.

We offer ADUs in multiple sizes and layouts:

  • 300–350 sq ft studio suites and backyard offices

  • 400–600 sq ft one-bedroom ADUs

  • 700–900 sq ft two-bedroom units

  • 1,000–1,200 sq ft full-size backyard homes

Plans can be adapted for guest suites, multigenerational living, home offices, rental units, wellness rooms, creative studios, or fully independent small homes.

Modern small house with black metal exterior and large glass sliding doors, surrounded by a wooden fence, grass, and landscaping.

Every ADU includes:

  • Concrete foundation or slab on grade system

  • Full framing + engineered structural components

  • High-performance insulation + air sealing

  • Modern siding (cedar, fiber cement, or stucco)

  • Energy efficient windows + doors

  • Standing seam metal or architectural shingle roofing

  • Complete electrical, plumbing, and HVAC systems

  • Full kitchen or kitchenette options

  • Modern bathrooms

  • Drywall, flooring, trim, and finish carpentry

We build ADUs the same way we build full homes: with durability, comfort, and long-term value at the forefront.

Modern tiny house with large glass windows, wooden siding accent, surrounded by landscaped garden with bushes, a small pond, and a paved path, during overcast sky.

For homeowners who want a higher architectural look, we also offer:

  • Corner glazing + large format window systems

  • Cedar soffits with integrated LED lighting

  • Level 5 smooth drywall

  • Premium siding packages

  • Radiant floor heating

  • Modern stucco or metal panel exteriors

  • Custom cabinetry + millwork

  • Premium tile + bathroom fixtures

You can keep it simple; or make it stunning. You choose.

A rooftop deck with outdoor seating, a small indoor kitchenette, a woman standing near the entrance, a kayak stored on the deck, and layered garden beds with trees and flowering shrubs in the background.

We guide you from the first conversation through the final inspection:

1. Feasibility & Site Review

We verify setbacks, utilities, slope, access, existing structures, and local zoning. AHERA asbestos inspection available for older homes.

2. Design Support & Plan Selection

Choose from our model ADUs (300, 600, 900, 1200 sq ft) or work with us to tailor the footprint and finish level to your needs.

3. Permitting & Engineering

We prepare construction drawings, structural engineering, and required permitting documentation.

4. Construction

Full foundation-to-finish building with clear communication and daily progress updates.

5. Final Inspection & Handover

We deliver a clean, turn-key ADU ready for guests, family, or tenants.

Construction workers building a small house on stilts. The house has beige and orange insulating panels, large windows, and a sloped roof. Ladders and construction tools are present, with trees and blue sky in the background.

Licensed, bonded, insured

  • AHERA-certified asbestos inspector for safe demo

  • Lead safe certified (RRP)

  • Clear, honest communication (no upselling, no pressure)

  • High quality craftsmanship with modern details

  • Local builder who understands Northwest conditions

  • Flexible design and finish options

Our goal is simple: build you a beautiful, durable ADU that fits your property and stands the test of time.