Plan HG-1047•Backyard ADU / Granny Flat•20' × 16' Footprint

322 Sq Ft (16x20) 1 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan

322 sq ft heated living • 1 Bedroom, 1 Bath • Free 2D CAD Blueprint (.SVG)

Download Free CAD (.SVG)

Room Dimensions & Zones

20' × 16' Shell

PRIMARY BEDROOM

74 sq ft

10'-6" × 7'-0"

BATH & LAUNDRY

67 sq ft

9'-6" × 7'-0"

GREAT ROOM & DINING

95 sq ft

10'-6" × 9'-0"

KITCHEN & ISLAND

86 sq ft

9'-6" × 9'-0"

Build Cost Estimator

Estimated Cost to Build (20' × 16' Backyard ADU / Granny Flat)

Region:

Shell / Building Kit

$15,000 – $19,500

Framing package, roof trusses & exterior shell for 320 sq ft base.

Owner-Builder

$41,500 – $54,500

Saves ~$18,500 by managing local slab & interior trades.

Turnkey Builder

$60,000 – $73,000

Full general contractor finish including slab, HVAC, kitchen & baths.

Est. Monthly Payment

$345 / mo

$53,200 financed (30-Yr)

Down Payment:20%

Interest Rate:6.75%

Free Vector CAD Blueprint • Plan HG-1047

Download 20' × 16' Backyard ADU / Granny Flat Floor Plan (.SVG)

Scalable 2D architectural vector drawing with exterior and room dimensions, door swings, and fixture layout. Opens in AutoCAD, Illustrator, Inkscape, or any browser.

Material Takeoff & Framing Specifications

Concrete volume (8 yd³), roof surface (~369 sq ft), wall framing & architectural notes

Building Package	Specification	Quantity	Est. Range
Structural Shell & Trusses	20'×16' 2x6 Dimensional Lumber Framing / Panelized SIP Option	320 sq ft shell kit	$15,000 – $19,500
Concrete Slab & Grade Beams	Stem Wall or Monolithic Concrete Slab-on-Grade	8 Cubic Yards (4,000 PSI)	$3,250 – $4,250
Roofing & Underlayment	Architectural Standing-Seam Shed / Low-Slope Gable (3:12 Pitch)	5 Roofing Squares (500 sq ft)	$2,100 – $3,400
Closed-Cell Spray Foam / Insulation	3" Closed-Cell Wall & Roof Deck Thermal Envelope (R-21 to R-38)	3,156 Board Feet	$4,261 – $5,839
Windows & Exterior Doors	Low-E Argon Black Architectural Glazing + 36" Fiberglass Entry	6 Windows • 3 Doors	$5,100 – $7,980
HVAC & Multi-Zone Mini-Split	High-SEER2 Heat Pump / Ductless Mini-Split System	1.5 Ton (18,000 BTU/hr)	$3,900 – $6,150

Exterior Perimeter

72 Linear Ft

Interior Partitions

~52 Linear Ft

Est. Concrete Slab

8 Cubic Yards

Roof Deck Area

~369 Sq Ft

Plan HG-1047 (322 Sq Ft (16x20) 1 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan) is an IRC R304/R310-vetted backyard adu / granny flat blueprint engineered around a 20'-0" × 16'-0" structural grid (320 sq ft base footprint, 0.8:1 Square-Bay Proportion). Configured on the Consolidated Wet-Wall + Open Great Room topology, this layout delivers 322 sq ft of conditioned residential living area and 63 sq ft of covered outdoor porch deck.

Inside the conditioned envelope, the floor plan is organized into 4 distinct architectural zones: PRIMARY BEDROOM (10'-6" × 7'-0", 74 sq ft), BATH & LAUNDRY (9'-6" × 7'-0", 67 sq ft), GREAT ROOM & DINING (10'-6" × 9'-0", 95 sq ft), KITCHEN & ISLAND (9'-6" × 9'-0", 86 sq ft). Plumbing rough-ins are consolidated across BATH & LAUNDRY, KITCHEN & ISLAND to minimize sub-slab trenching and manifold pipe runs. Sleeping quarters (PRIMARY BEDROOM at 74 sq ft) are acoustically buffered from the primary living core and positioned on exterior elevations for code-compliant egress glazing.

From a builder takeoff standpoint, the 20' clear-span width utilizes 2x6 dimensional lumber framing / panelized sip option bearing on 72 linear feet of 6" exterior wall framing (~97 framing studs/posts) and 52 linear feet of interior partitions. The 3:12 architectural standing-seam shed / low-slope gable requires approximately 369 sq ft of roofing material (5 roofing squares), while the stem wall or monolithic concrete slab-on-grade pours at an estimated 8 cubic yards of 4,000-PSI concrete.

Frequently Asked Questions • Plan HG-1047

Building costs, foundation specs, egress & CAD customization questions

How much does it cost to build the 20x16 322 Sq Ft (16x20) 1 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan (HG-1047)?

Based on current national residential construction data for backyard adu / granny flat structures, the dried-in structural shell for Plan HG-1047 (320 sq ft base footprint) ranges from $15,000 to $19,500 ($48/sq ft baseline). A complete turnkey build—including the 8-yard concrete foundation, 52 linear feet of interior framing, MEP rough-ins for 1 bath(s), and interior finishes across 322 sq ft of heated space—ranges from $60,000 to $73,000. Use the interactive Regional Cost Multiplier on this page to adjust for your local labor market and owner-builder sweat equity.

What are the exact room dimensions inside this 322 sq ft 1-bedroom layout?

Plan HG-1047 features 4 architecturally solved spaces inside its 20' × 16' footprint: PRIMARY BEDROOM (10'-6" × 7'-0", 74 sq ft), BATH & LAUNDRY (9'-6" × 7'-0", 67 sq ft), GREAT ROOM & DINING (10'-6" × 9'-0", 95 sq ft), KITCHEN & ISLAND (9'-6" × 9'-0", 86 sq ft). Every habitable room meets or exceeds IRC R304 minimum area (70+ sq ft) and minimum horizontal dimension (7'-0"+) requirements.

Can this 20' × 16' floor plan be built with post-frame, red-iron steel, or 2x6 stick framing?

Yes. Because the outer envelope is engineered on an even 20'-0" × 16'-0" structural grid (72 LF perimeter) with clear-span 3:12 trusses, a local structural engineer or building kit supplier can adapt the blueprint for 2x6 Dimensional Lumber Framing / Panelized SIP Option, conventional 2x6 stick framing at 16" o.c., laminated post-frame columns at 8' o.c., or structural insulated panels (SIPs).

What files are included in the free CAD blueprint download for Plan HG-1047?

Downloading Plan HG-1047 provides the high-resolution scalable vector floor plan (.SVG) with crisp architectural lineweights, exterior dimension strings (20'-0" × 16'-0"), room-by-room callouts, door swing arcs, and window schedules, plus instant browser printing for contractor bidding and preliminary municipal zoning review.