Trusted Federal Way ADU Builders for Detached and Attached Units
Want a rental unit, guest house, or more room for family? BB-Builders Pro is a team of ADU builders serving Federal Way. We design, permit, and build backyard cottages, garage conversions, and accessory dwelling unit additions. State law now allows up to two ADUs per lot, so there is more room to add value than ever. We handle the full build, from site evaluation to final walkthrough, on your schedule.
Trusted Family Owned Remodeling Service
Our licensed crew has built detached and attached ADUs across Federal Way and King County with careful, lasting craft.
We draw custom ADU floor plans that fit your Federal Way lot, your main house, and how your family plans to use the space.
Federal Way zoning and the two-ADU rule can feel like a maze. We handle each permit step so your build meets all code rules.
We build with durable, high-performance materials that cut upkeep, last decades, and keep monthly power bills low.
From the first consultation and 3D renderings through the final walkthrough, we run every stage of your Federal Way ADU build.
BB-Builders Pro covers every part of your ADU project, from first sketch to final sign-off in Federal Way. Our services include:
Build a standalone, fully livable cottage in your Federal Way backyard, ideal for rental income, aging parents, or guests.
Convert your garage or spare interior room into a fully livable attached ADU, adding a home without a separate building footprint.
Planning ahead? We build yard additions and outbuildings designed to support a future detached ADU on your Federal Way lot.
We draft tailor-made ADU floor plans and layouts shaped to your Federal Way lot, your budget, and your long-term goals.
We handle every permit, zoning approval, and Federal Way requirement, keeping your ADU construction smooth and legal.
Already have an ADU or aging home extension? We take on renovations, interior upgrades, and energy-efficient improvements too.
Testimonials
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We visit your Federal Way property, talk through your goals, and give honest advice on the best ADU or home plan for your lot.
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Our designers draw detailed blueprints and 3D models, so you can picture your ADU or home addition clearly before we break ground.
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We handle every permit, zoning rule, and Federal Way code requirement, so you never have to sort out the legal side yourself.
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Our skilled crew preps the site and builds with care, keeping the work clean, efficient, and low-impact on your daily life.
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When the build wraps, we run a full inspection and walkthrough, confirming every detail meets safety and quality standards.
An ADU is a secondary home on a single-family lot, either attached to the main house or built as a separate detached structure. Federal Way allows up to two ADUs on a qualifying lot, including junior ADUs. Both attached and detached units are permitted, giving homeowners more flexibility than before.
An ADU adds rental income, housing for aging parents, or a private guest space. It uses land you already own, so it builds value without buying more property. With Federal Way allowing two units per lot, the earning and living options are wider than before.
Yes. Every ADU in Federal Way needs a building permit, plus zoning and code review through the city’s Permit Center. Detached units, junior ADUs, and garage conversions each carry their own rules. We prepare the full application and manage it so your project stays compliant.
Cost depends on size, type, and finishes. A garage conversion runs the least, while a large detached cottage costs the most. Utility connections and site work add to the total. We give you one written estimate after a free on-site visit.
Most ADUs take a few months from permit approval to move-in. Design and permitting add time before the build starts. Detached units usually take longer than conversions. We map out the full schedule before any work begins.
Yes. Federal Way does not require owner-occupancy for newly built ADUs, so a second unit works as long-term rental income. That makes an ADU a real investment option. Short-term rentals follow separate city rules, which we can point you to.
Detached ADUs can be up to 1,000 square feet. Attached ADUs are capped at half the primary home’s living area or 1,000 square feet, whichever is less. Junior ADUs are limited to 500 square feet. We design to the largest unit your lot allows.
Federal Way generally limits detached ADUs to 16 feet in height, with some flexibility based on design and placement. That keeps backyard cottages in scale with neighboring homes. We plan the roofline early so the design clears review without costly changes.
Not always. Some ADUs share water and power with the main house, while others need separate connections depending on size and layout. Separate meters help if you plan to rent. We assess your utilities during the site evaluation.
Yes. A garage conversion is one of the most affordable ways to add an attached ADU, since the structure already exists. It still needs permits, insulation, and code-compliant systems. We handle the conversion from design through final inspection.
Usually yes. Adding livable square footage raises your assessed value, so property taxes typically go up. The added rental income or home value often outweighs the increase. The King County assessor sets the exact change after the build.
Simple Financing Options
Discover the perfect financing solution for your remodeling project. We provide tailored options to suit your budget and ensure your dream home becomes a reality.
Contact us today for a free consultation, and let’s begin transforming your house into the home you’ve always wanted.
Contact us today for a free consultation, and let’s begin transforming your house into the home you’ve always wanted.