ADU Builders & Remodeling Contractor in Lacey, WA
Lacey’s Trusted Partner in ADU and Tiny Home Construction
Lacey homeowners are staying put. With most mortgages in the low threes and Thurston County’s median home hovering near $532,000, moving up no longer pencils out the way it did five years ago. That’s why many homeowners are choosing to invest into the properties they already own.
Mallard Brothers Construction is a design-build general contractor based in Olympia, working throughout Lacey from Hawks Prairie and Meridian to Tanglewilde, Woodland Creek, and the neighborhoods off Carpenter and Marvin Road. We build accessory dwelling units, additions, tiny homes, and whole-home remodels. One team, from the first site visit through final inspection.
Building an ADU in Lacey
Washington’s HB 1337 changed the math for Lacey property owners. Inside the urban growth area, cities must now allow at least two ADUs per lot, cannot require the owner to live on site, and cannot cap ADU floor area below 1,000 square feet. Practically, that means a Lacey homeowner can build a full second dwelling: one that appraises, finances, and rents.
Lacey administers ADUs under Lacey Municipal Code 14.23, which sets design criteria intended to keep the accessory unit visually subordinate to the main house. That chapter also gives the administrator discretion to approve a larger unit than the base standard in specific circumstances. For instance, when the ADU is being carved out of an existing structure and the logical use of the floor plan exceeds the size limit.
Lacey has also been unusually forward-leaning here. The city commissioned local architects to develop ADU designs specifically for Lacey lots, part of a broader regional push to make small-scale infill housing easier to permit.
What we build in Lacey
Mallard Brothers offers a variety of ADU types to fit your property and lifestyle.
Attached ADUs
Connected to the main home but with private entrances, providing independence within proximity.
Detached ADUs (DADUs)
Stand-alone units that offer privacy and versatility for guests, rentals, or workspaces.
Garage Conversions
Transform your garage into a livable space while navigating Thurston County codes around wells and septic systems.
Custom Tiny Homes
Eco-friendly and efficient, designed for minimal living without sacrificing comfort.
Remodeling and Additions in Lacey
We take on substantial remodels, whole-home renovations, structural additions, and full-floor reconfigurations, typically starting around $100,000.
Lacey’s housing stock shapes what we’re asked to do. The 1970s and ’80s ranches through the older Lacey core have good bones with closed, compartmentalized floor plans. Most of our work there is opening up the main level and reworking the kitchen as the center of it. The Hawks Prairie builds from the ’90s and 2000s tend to come to us for primary suite additions, garage-to-living conversions, and second-story additions where the lot won’t allow a footprint expansion.
For reference, in 2026 our 800-square-foot Olympia addition won the Olympia Master Builders REX Award for Addition Over $250,000.
The septic question
This is the single most consequential variable on a Lacey ADU, and it’s the one almost nobody addresses before they’ve already paid for drawings.
Much of Lacey sits on city sewer, and those properties permit relatively cleanly. But a meaningful share of the Lacey UGA, particularly on the eastern and southern edges toward Meridian Campus and the unincorporated fringe, remains on septic. On a septic property, adding a second dwelling means demonstrating your existing system has the capacity for additional bedrooms, as well as enough land to absorb the waste. This might require a site evaluation, a design update, or in some cases a full system replacement. That’s an expensive upgrade, and it’s one you’ll want to know about at the beginning of your project.
We will answer this in the first part of a Design Contract. If your lot won’t support what you’re imagining, we’d rather find out with a very limited investment so we can recommend a different direction.
What we remodel
Building an ADU with Mallard Brothers is collaborative process
Initial Consultation and Feasibility Study
We assess your property’s requirements, including zoning, sewer, and septic capacity, to determine the best path forward.
Design and Planning
Choose from pre-approved plans or work with our designers to create a custom layout that fits your unique needs.
Permits and Approvals
Our team handles all necessary permits and regulations, ensuring full compliance for a worry-free build.
Construction and Finalization
From utility connections to finishing touches, our skilled team completes your ADU with precision and quality, ready for move-in.
Customization Options
Our ADUs are designed with flexibility in mind, allowing you to customize features to suit your preferences and lifestyle
Interior and Exterior Design
Outdoor Spaces
Energy-Efficiency Features
Frequently Asked ADU Questions
Ready to Find Out What Your Lacey Property Can Support?
Provide your address, your lot size, whether you’re on sewer or septic, and what you’re picturing. We’ll come out, walk the property, and give you an answer on feasibility and budget at no cost.