Prefab ADU Companies
A prefab ADU company designs and factory-builds a complete backyard dwelling, then trucks or cranes it onto your lot, so the months of noise and mud happen in a plant rather than in your yard. This is the page for manufacturers selling a finished, permit-ready unit, usually 300 to 1,200 square feet, not a kit and not a set of plans. Full-size factory-built houses sit under modular home manufacturers instead. The companies worth your time publish all-in pricing, run the permit for you, show real floor plans with real dimensions, and install with crews they control. We rank on how much of the process a company owns end to end, install speed, and how honest the finished number is.
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Award-winning sustainable ADU builder serving 23 California counties. Combines customizable factory-built homes with deep local permitting expertise and 40 years of real estate experience.
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Factory-built backyard homes from 385 to 1,195 square feet with one-day crane installation and transparent pricing, serving California and Seattle with complete permitting and design.
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Nevada manufacturer of foldable Casita dwellings that compress into a box for shipment, then unfold and set up on-site in about an hour. Finished, permitted, and move-in-ready, with a full suite of built-in appliances and utilities. Nasdaq-traded company with a proven production model.
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Colorado prefab manufacturer of high-performance modular dwellings with three residential ADU sizes from 420 to 714 square feet, emphasizing natural materials, exceptional insulation, and sustainable construction practices.
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Oakland-based prefab ADU maker emphasizing contemporary design and flexible site delivery. Seven models from 172 to 800 square feet with voluminous interior spaces and up to 13-foot ceilings.
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Los Angeles prefab home designer and builder offering fully custom architect-grade ADUs with panelized manufacturing, serving all of Southern California with fixed pricing and 6–8 week installation.
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California-based prefab ADU maker offering rapid factory production (4-6 weeks) with fixed pricing at $412 per square foot. Models range from studios to 2-bedroom units with high-performance glazing.
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California prefab ADU builder offering one-, two-, and three-bedroom models from 450 to 1,200 square feet with customizable layouts and pricing starting around $200,000.
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Portland-based maker of sustainable teak-wood prefab ADUs, from studios to two-bedrooms, built in a factory and installed turnkey including permitting and foundation work.
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Boulder, Colorado manufacturer of modular steel-frame Flex-Flats ADUs, 245–735 square feet, engineered for durability and built 90% complete in the factory then installed in one day via crane.
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Southern California panel-based building system specialist founded from LivingHomes, achieving carbon neutrality in 2020 and delivering custom-designed prefab homes in half the time of site-built construction.
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Designer prefab ADU company offering five Backyard models from 420 to 950 square feet, starting at $152,000, with 3D customization tools, financing options, and installation within eight weeks in California.
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Colorado-based manufacturer of factory-built modular ADUs from 360 to 1,230 square feet, with six models ranging from studios to three-bedroom homes delivered complete and ready for occupancy.
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Houston-based modular ADU builder offering factory-built, foundation-set units from studios to one-bedrooms, designed by architects and built in controlled factory conditions for faster installation.
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Colorado factory builder of compact, energy-efficient prefab ADUs ranging from 160 to 700 square feet, with emphasis on off-grid capability and sustainable design. Models arrive finished and ready to install.
Frequently asked questions
What is the difference between a prefab ADU and an ADU kit?
A prefab company builds a finished, permit-ready home in a factory rather than just providing materials. These units are delivered to your lot fully assembled and ready for installation.
How much construction time should I expect on my property?
Since most of the work happens off-site in a factory, the installation on your lot is very fast. Some companies can crane a complete unit into place in a single day.
What sizes of prefab ADUs are available?
Options vary depending on the manufacturer, but you can find everything from small 385-square-foot studios to larger three-bedroom homes around 1,195 square feet. This allows you to choose a model that fits your specific lot and needs.