Plan HG-1150•Backyard ADU / Granny Flat•28' × 20' Footprint

562 Sq Ft (20x28) 2 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan

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

Download Free CAD (.SVG)

Room Dimensions & Zones

28' × 20' Shell

PRIMARY SUITE

131 sq ft

14'-6" × 9'-0"

BEDROOM 2

122 sq ft

13'-6" × 9'-0"

GREAT ROOM & DINING

193 sq ft

17'-6" × 11'-0"

BATH & LAUNDRY

53 sq ft

10'-6" × 5'-0"

KITCHEN & ISLAND

63 sq ft

10'-6" × 6'-0"

Build Cost Estimator

Estimated Cost to Build (28' × 20' Backyard ADU / Granny Flat)

Region:

Shell / Building Kit

$26,500 – $33,500

Framing package, roof trusses & exterior shell for 560 sq ft base.

Owner-Builder

$71,500 – $94,500

Saves ~$32,500 by managing local slab & interior trades.

Turnkey Builder

$104,000 – $127,000

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

Est. Monthly Payment

$599 / mo

$92,400 financed (30-Yr)

Down Payment:20%

Interest Rate:6.75%

Free Vector CAD Blueprint • Plan HG-1150

Download 28' × 20' 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 (13 yd³), roof surface (~647 sq ft), wall framing & architectural notes

Building Package	Specification	Quantity	Est. Range
Structural Shell & Trusses	28'×20' 2x6 Dimensional Lumber Framing / Panelized SIP Option	560 sq ft shell kit	$26,500 – $33,500
Concrete Slab & Grade Beams	Stem Wall or Monolithic Concrete Slab-on-Grade	13 Cubic Yards (4,000 PSI)	$5,750 – $7,250
Roofing & Underlayment	Architectural Standing-Seam Shed / Low-Slope Gable (3:12 Pitch)	8 Roofing Squares (800 sq ft)	$3,360 – $5,440
Closed-Cell Spray Foam / Insulation	3" Closed-Cell Wall & Roof Deck Thermal Envelope (R-21 to R-38)	4,668 Board Feet	$6,302 – $8,636
Windows & Exterior Doors	Low-E Argon Black Architectural Glazing + 36" Fiberglass Entry	5 Windows • 4 Doors	$4,450 – $7,000
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

96 Linear Ft

Interior Partitions

~77 Linear Ft

Est. Concrete Slab

13 Cubic Yards

Roof Deck Area

~647 Sq Ft

Plan HG-1150 (562 Sq Ft (20x28) 2 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan) is an IRC R304/R310-vetted backyard adu / granny flat blueprint engineered around a 28'-0" × 20'-0" structural grid (560 sq ft base footprint, 0.71:1 Square-Bay Proportion). Configured on the Consolidated Wet-Wall + Open Great Room topology, this layout delivers 562 sq ft of conditioned residential living area and 105 sq ft of covered outdoor porch deck.

Inside the conditioned envelope, the floor plan is organized into 5 distinct architectural zones: PRIMARY SUITE (14'-6" × 9'-0", 131 sq ft), BEDROOM 2 (13'-6" × 9'-0", 122 sq ft), GREAT ROOM & DINING (17'-6" × 11'-0", 193 sq ft), BATH & LAUNDRY (10'-6" × 5'-0", 53 sq ft), KITCHEN & ISLAND (10'-6" × 6'-0", 63 sq ft). Plumbing rough-ins are consolidated across BATH & LAUNDRY, KITCHEN & ISLAND to minimize sub-slab trenching and manifold pipe runs. Sleeping quarters (PRIMARY SUITE at 131 sq ft; BEDROOM 2 at 122 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 28' clear-span width utilizes 2x6 dimensional lumber framing / panelized sip option bearing on 96 linear feet of 6" exterior wall framing (~118 framing studs/posts) and 77 linear feet of interior partitions. The 3:12 architectural standing-seam shed / low-slope gable requires approximately 647 sq ft of roofing material (8 roofing squares), while the stem wall or monolithic concrete slab-on-grade pours at an estimated 13 cubic yards of 4,000-PSI concrete.

Frequently Asked Questions • Plan HG-1150

Building costs, foundation specs, egress & CAD customization questions

How much does it cost to build the 28x20 562 Sq Ft (20x28) 2 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan (HG-1150)?

Based on current national residential construction data for backyard adu / granny flat structures, the dried-in structural shell for Plan HG-1150 (560 sq ft base footprint) ranges from $26,500 to $33,500 ($48/sq ft baseline). A complete turnkey build—including the 13-yard concrete foundation, 77 linear feet of interior framing, MEP rough-ins for 1 bath(s), and interior finishes across 562 sq ft of heated space—ranges from $104,000 to $127,000. 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 562 sq ft 2-bedroom layout?

Plan HG-1150 features 5 architecturally solved spaces inside its 28' × 20' footprint: PRIMARY SUITE (14'-6" × 9'-0", 131 sq ft), BEDROOM 2 (13'-6" × 9'-0", 122 sq ft), GREAT ROOM & DINING (17'-6" × 11'-0", 193 sq ft), BATH & LAUNDRY (10'-6" × 5'-0", 53 sq ft), KITCHEN & ISLAND (10'-6" × 6'-0", 63 sq ft). Every habitable room meets or exceeds IRC R304 minimum area (70+ sq ft) and minimum horizontal dimension (7'-0"+) requirements.

Can this 28' × 20' floor plan be built with post-frame, red-iron steel, or 2x6 stick framing?

Yes. Because the outer envelope is engineered on an even 28'-0" × 20'-0" structural grid (96 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-1150?

Downloading Plan HG-1150 provides the high-resolution scalable vector floor plan (.SVG) with crisp architectural lineweights, exterior dimension strings (28'-0" × 20'-0"), room-by-room callouts, door swing arcs, and window schedules, plus instant browser printing for contractor bidding and preliminary municipal zoning review.