This compact, modern ADU (Accessory Dwelling Unit) offers a smart and stylish solution for ancillary living. With **479 sq ft** of heated space, it includes **1 bedroom**, **1 full bath**, and a **covered patio** (≈ 90 sq ft). 0
Floor Plan Highlights: The layout is tight but efficient. The main living area opens directly into kitchen and dining zones, allowing seamless flow. The bathroom is full sized and the bedroom is positioned to enjoy privacy, yet everything remains within easy reach. 1

Exterior & Architectural Form
The exterior is decidedly contemporary. The roof is framed with a **1-on-12 slope** (a very shallow pitch), giving it a nearly flat appearance but still enabling drainage. 2 Exterior walls are **2×6** framing for durability and insulation potential. 3
Footprint dimensions are **28′ wide** by **20′ deep**, with a maximum ridge height of **12′-0″**. 4 The small covered patio adds weather protection and a degree of indoor/outdoor connection. 5
Interior Layout & Function
Enter into a combined living/kitchen/dining zone. Because the space is modest, functions overlap intentionally—cooking, eating, and relaxing happen side by side. Natural light and minimal partitioning help the space feel larger.
The bedroom is separated enough to allow retreat from the common area. The bathroom is full size (i.e. includes shower, toilet, vanity) and positioned to be accessible without intruding on privacy.
Bedroom & Bath Details
The single bedroom accommodates typical furnishings (bed, side tables, wardrobe) while maintaining circulation. The layout aims to minimize wasted area. The bath includes full fixtures—a thoughtful inclusion in an ADU of this size.
Bathroom plumbing is located close to kitchen plumbing for efficient plumbing runs and cost control.
Covered Patio / Outdoor Connection
A **90 sq ft covered patio** extends the usable footprint outdoors and offers a sheltered transition between interior and exterior. 6 Though small, it gives you a place for seating or a small grill and enhances livability.
Construction & Efficiency Notes
Ceiling height on the first floor is **9′**, balancing volume and economy. 7 The shallow roof pitch simplifies framing but requires careful flashing and drainage design to avoid water intrusion issues. 8
The compact dimensions and few internal partitions reduce construction waste and make mechanical / plumbing systems more efficient. Shared walls and direct utility alignment help keep costs down.
Estimated Building Cost
An ADU of this scale, with contemporary detailing and efficient layout, might cost in the U.S. between **$80,000 – $140,000**, depending on site work, finishes, utilities, building codes, and labor. Because of its small footprint, the cost per square foot tends to be higher than large homes, so design and systems efficiency matter more.
Benefits & Use Cases
Plan 420185WNT is ideal for guest houses, in-law suites, rental units, or extra family space. Its compact modern aesthetic fits well behind existing homes or in tight lots. The full bath and bedroom make it a fully functional standalone unit. Because it’s economical yet thoughtful, it strikes a balance between utility and design.