Converting an existing garage into an ADU is one of the most cost-effective ways to add a livable unit to your Seattle property. Because the structure already exists, you avoid the cost of building a foundation and framing from scratch. That said, a garage conversion is not a simple renovation. Garages are built to house vehicles, not people, and bringing a garage up to residential standards requires significant work. The question is not whether it can be done, but whether it makes sense for your specific property and goals. The first thing to evaluate is the garage’s structural condition. Older garages in Seattle often have minimal insulation, concrete slab floors that sit below grade, and framing that was not designed to support the loads required for a finished living space. A thorough inspection will identify whether the existing structure can be upgraded or whether it needs to be partially rebuilt. At AmyWorks, we assess the garage before providing any estimate, because the structural condition is the biggest variable in the overall project cost. The next consideration is utility connections. A livable ADU requires plumbing, electrical service, and heating. If your garage is detached, running new utility lines from the main house or from the street adds to the project cost and complexity. If the garage is attached to the house, the connections are typically simpler and less expensive. Seattle also requires that ADUs meet specific standards for natural light and ventilation, which often means adding windows or a skylight to a space that was designed to be dark and utilitarian. From a permitting standpoint, a garage conversion to an ADU in Seattle is treated the same as any other ADU project. You will need building, plumbing, electrical, and mechanical permits, and the finished unit must meet all residential building codes. One common question is about parking: Seattle’s updated ADU rules have largely eliminated the off-street parking replacement requirement for ADU conversions, which makes the process more straightforward than it used to be. AmyWorks handles the entire permitting process, coordinating with SDCI and the relevant trade inspectors to keep the project on track. Contact us to find out if your garage is a good candidate for conversion.