PLAN 25186 · HOME PLAN BLUEPRINT

20x20 Tiny House Plan | 400 Sq Ft 1 Bedroom ADU Blueprint

Name: 20x20 Tiny House Plan | 400 Sq Ft 1 Bedroom ADU Blueprint
Brand: HomePlanDIY
SKU: 25186
Price: 449.0 USD
Availability: InStock
Rating: 5.0 (2 reviews)

★★★★★ 5.0 30+ downloads

400sq ft

1bed

1.0bath

20'x20'footprint

Noloft

About this plan

Build a 400 sq ft tiny house, backyard ADU, or guest house with this complete 20x20 one-bedroom plan. The single-story layout includes an open living and kitchen area, full bathroom with tub, in-unit washer/dryer, closet, and a loft plan — perfect for rental income, aging parents, or a first home. Instant digital download includes print-ready PDF plans, CAD file, itemized material list, and a reverse plan depending on your package. Every sheet is included: floor plans, elevations, sections, foundation, framing, electrical, and plumbing. Estimated build cost: $52,000–$88,000.

What's included — 23 professional sheets

Every set ships as print-ready PDF and editable CAD, drawn to 2021/2022 IRC standards.

Ground Floor Plan

Loft Plan

Slab Plan w/ Load-Bearing Walls

Sections in Floor Plan

Ceiling Outline

Roof Outline & Framing

Section A-A'

Section B-B'

East Elevation

West Elevation

North Elevation

South Elevation

Toilet Details

Kitchen Details

Rafter Details

Wall Details

Wall & Window Details

Exterior Wall Foundation Details

Door & Window Schedule

Framing Details

Electrical Plan

Plumbing Plan

Complete Material List

Full specifications

Plan number	25186
Style	Home Plan Blueprint
Heated area	400 sq ft (ANSI Z765)
Width and depth	20'x20'
Floors	1.5
Roof pitch	9:12
Roof style	Steep gable
Framing	2x4
Garage detail	0
Foundation	Slab/Pier
Design standard	2021/2022 IRC with amendments
Files delivered	Print-ready PDF + editable CAD (.dwg)
License	Single-use construction license
Delivery	Instant download + email, lifetime re-download

What will it cost to build?

Pick your state or set your own rate. We'll estimate from this plan's 400 sq ft.

$90/sq ft · owner-builder$125/sq ft$250/sq ft · high finish

Estimated construction cost (±15%) · excludes land, site work & permits. Owner-builders doing their own labor routinely come in 20–40% under.

Building codes & your state

Please read before ordering. Our plans are drawn to 2021/2022 IRC standards. They do not include site-specific earthquake seismic or wind engineering (CA, OR, WA, NV residents take note). Coastal GA, SC & NC may require hurricane/wind engineering. Many states (incl. FL, NY, NJ, CO, PA and others) may require a locally licensed engineer or architect to review and seal plans before permitting. Call your local building department before placing your order — and remember our editable CAD files are designed to make that local review fast and inexpensive. Need help? Our engineering-stamp coordination service connects you with a licensed professional in your state.