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ADU Kits

An ADU (accessory dwelling unit) is a second, self-contained building on your lot: a guest house, in-law suite, rental studio or home office. Our prefab ADU kits are modern ALU Concept buildings from Garden House 24, with solid Nordic spruce walls, aluminum framing and large glass doors, shipped flat-packed for DIY assembly or professional installation.

Prefab ADU Kits for Backyard Living

Kits run from $12,063 to $29,682 and from about 88 sq ft to about 370 sq ft. Choose an open studio for a guest room or office, a 1-bedroom suite with a separate sleeping area, or a multi-room layout. Walls come in 44 mm for mild climates or 70 mm for year-round comfort.

What Comes in an ADU Kit

  • Included: pre-cut spruce wall and roof parts, doors, windows and a floor, shipped as a closed shell with internal walls where the plan has them.
  • Optional extras: roofing cover and rain gutters.
  • Not included: foundation, insulation, plumbing, electrical, interior finishes and permits. These usually cost more than the kit itself, so budget for them early.

Plan Your ADU

An ADU is a dwelling, so it needs a building permit and must meet local zoning rules for size, height, setbacks and parking. Start with our permit guide. Need more space or a finished build? See our backyard guest suites and tiny homes.

ADU Kits FAQs

1. Is a prefab ADU cheaper than building?
Usually, yes. A prefab ADU kit removes most framing labor and design time, and the shell goes up in days instead of weeks. Our ADU kits run from $12,063 to $29,682 for the kit. Your finished cost will be higher once you add foundation, utilities, finishes and permits.

2. What is the cheapest way to build an ADU?
Pick the smallest floor plan that meets your needs, a DIY kit shell, and a site close to existing utilities. A studio layout without a full kitchen keeps plumbing costs down. Converting a garage can also be cheaper where allowed.

3. What sizes do your ADU kits come in?
From about 88 sq ft studios to about 370 sq ft with a bedroom or multiple rooms. Each product page lists the exact footprint, wall thickness and ridge height.

4. Will an ADU raise my property taxes?
Usually yes, for the added value of the new unit. In many areas the assessor adds the ADU's value without reassessing your main home. Check with your county appraisal district.

5. How do I connect water, sewer and power to an ADU?
Most ADUs connect to the main house's utilities through trenched lines for water, sewer and electrical. If you plan to rent it, ask about separate meters or sub-meters. Licensed trades and permits are required.

6. Do I need a permit for an ADU?
Yes. An ADU is a dwelling, so it needs a building permit and must meet local zoning (size, height, setbacks, parking). Start with our permit guide, then book a free design consultation.

7. What are the downsides of prefab ADUs?
Floor plans are set, delivery and site access need planning, and the kit price is not the finished price. You still need a foundation, utilities, finishing and permits. Planning those early avoids surprises.