Plan HG-1649•Duplex / Multi-Gen•40' × 28' Footprint

1,120 Sq Ft (28x40) 3 Bed 2 Bath Duplex / Multi-Gen Floor Plan (STC-60 Mirrored Acoustic Party-Wall Duplex)

1,120 sq ft heated living • 3 Bedrooms, 2 Baths • Free 2D CAD Blueprint (.SVG)

Download Free CAD (.SVG)

Room Dimensions & Zones

40' × 28' Shell

UNIT A SUITE

150 sq ft

12'-0" × 12'-6"

UNIT A BATH

100 sq ft

8'-0" × 12'-6"

UNIT A LIVING

186 sq ft

12'-0" × 15'-6"

UNIT A KITCHEN

124 sq ft

8'-0" × 15'-6"

UNIT B BATH

100 sq ft

8'-0" × 12'-6"

UNIT B SUITE

150 sq ft

12'-0" × 12'-6"

UNIT B KITCHEN

124 sq ft

8'-0" × 15'-6"

UNIT B LIVING

186 sq ft

12'-0" × 15'-6"

Build Cost Estimator

Estimated Cost to Build (40' × 28' Duplex / Multi-Gen)

Region:

Shell / Building Kit

$45,000 – $57,500

Framing package, roof trusses & exterior shell for 1,120 sq ft base.

Owner-Builder

$116,000 – $153,000

Saves ~$52,000 by managing local slab & interior trades.

Turnkey Builder

$168,000 – $205,000

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

Est. Monthly Payment

$968 / mo

$149,200 financed (30-Yr)

Down Payment:20%

Interest Rate:6.75%

Free Vector CAD Blueprint • Plan HG-1649

Download 40' × 28' Duplex / Multi-Gen 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 (22 yd³), roof surface (~1,359 sq ft), wall framing & architectural notes

Building Package	Specification	Quantity	Est. Range
Structural Shell & Trusses	40'×28' 2x6 Exterior + Double-Stud Insulated Acoustic Party Wall	1,120 sq ft shell kit	$45,000 – $57,500
Concrete Slab & Grade Beams	Monolithic Concrete Slab w/ Dual Sewer/Water Stub-Outs	22 Cubic Yards (4,000 PSI)	$11,500 – $14,750
Roofing & Underlayment	Architectural Shingle or Standing Seam Metal Hip/Gable (5:12 Pitch)	17 Roofing Squares (1,700 sq ft)	$7,140 – $11,560
Closed-Cell Spray Foam / Insulation	3" Closed-Cell Wall & Roof Deck Thermal Envelope (R-21 to R-38)	7,740 Board Feet	$10,449 – $14,319
Windows & Exterior Doors	Low-E Argon Black Architectural Glazing + 36" Fiberglass Entry	4 Windows • 6 Doors	$3,800 – $6,020
HVAC & Multi-Zone Mini-Split	High-SEER2 Heat Pump / Ductless Mini-Split System	2 Ton (24,000 BTU/hr)	$5,200 – $8,200

Exterior Perimeter

136 Linear Ft

Interior Partitions

~138 Linear Ft

Est. Concrete Slab

22 Cubic Yards

Roof Deck Area

~1,359 Sq Ft

Plan HG-1649 (1,120 Sq Ft (28x40) 3 Bed 2 Bath Duplex / Multi-Gen Floor Plan (STC-60 Mirrored Acoustic Party-Wall Duplex)) is an IRC R304/R310-vetted duplex / multi-gen blueprint engineered around a 40'-0" × 28'-0" structural grid (1,120 sq ft base footprint, 0.7:1 Square-Bay Proportion). Configured on the STC-60 Mirrored Acoustic Party-Wall Duplex topology, this layout delivers 1,120 sq ft of conditioned residential living area and 240 sq ft of covered outdoor porch deck.

Inside the conditioned envelope, the floor plan is organized into 8 distinct architectural zones: UNIT A SUITE (12'-0" × 12'-6", 150 sq ft), UNIT A BATH (8'-0" × 12'-6", 100 sq ft), UNIT A LIVING (12'-0" × 15'-6", 186 sq ft), UNIT A KITCHEN (8'-0" × 15'-6", 124 sq ft), UNIT B BATH (8'-0" × 12'-6", 100 sq ft), UNIT B SUITE (12'-0" × 12'-6", 150 sq ft). Plumbing rough-ins are consolidated across UNIT A BATH, UNIT A KITCHEN, UNIT B BATH, UNIT B KITCHEN to minimize sub-slab trenching and manifold pipe runs. Sleeping quarters (UNIT A SUITE at 150 sq ft; UNIT B SUITE at 150 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 40' clear-span width utilizes 2x6 exterior + double-stud insulated acoustic party wall bearing on 136 linear feet of 6" exterior wall framing (~156 framing studs/posts) and 138 linear feet of interior partitions. The 5:12 architectural shingle or standing seam metal hip/gable requires approximately 1,359 sq ft of roofing material (17 roofing squares), while the monolithic concrete slab w/ dual sewer/water stub-outs pours at an estimated 22 cubic yards of 4,000-PSI concrete.

Frequently Asked Questions • Plan HG-1649

Building costs, foundation specs, egress & CAD customization questions

How much does it cost to build the 40x28 1,120 Sq Ft (28x40) 3 Bed 2 Bath Duplex / Multi-Gen Floor Plan (STC-60 Mirrored Acoustic Party-Wall Duplex) (HG-1649)?

Based on current national residential construction data for duplex / multi-gen structures, the dried-in structural shell for Plan HG-1649 (1,120 sq ft base footprint) ranges from $45,000 to $57,500 ($40/sq ft baseline). A complete turnkey build—including the 22-yard concrete foundation, 138 linear feet of interior framing, MEP rough-ins for 2 bath(s), and interior finishes across 1,120 sq ft of heated space—ranges from $168,000 to $205,000. 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 1,120 sq ft 3-bedroom layout?

Plan HG-1649 features 8 architecturally solved spaces inside its 40' × 28' footprint: UNIT A SUITE (12'-0" × 12'-6", 150 sq ft), UNIT A BATH (8'-0" × 12'-6", 100 sq ft), UNIT A LIVING (12'-0" × 15'-6", 186 sq ft), UNIT A KITCHEN (8'-0" × 15'-6", 124 sq ft), UNIT B BATH (8'-0" × 12'-6", 100 sq ft), UNIT B SUITE (12'-0" × 12'-6", 150 sq ft), UNIT B KITCHEN (8'-0" × 15'-6", 124 sq ft), UNIT B LIVING (12'-0" × 15'-6", 186 sq ft). Every habitable room meets or exceeds IRC R304 minimum area (70+ sq ft) and minimum horizontal dimension (7'-0"+) requirements.

Can this 40' × 28' floor plan be built with post-frame, red-iron steel, or 2x6 stick framing?

Yes. Because the outer envelope is engineered on an even 40'-0" × 28'-0" structural grid (136 LF perimeter) with clear-span 5:12 trusses, a local structural engineer or building kit supplier can adapt the blueprint for 2x6 Exterior + Double-Stud Insulated Acoustic Party Wall, 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-1649?

Downloading Plan HG-1649 provides the high-resolution scalable vector floor plan (.SVG) with crisp architectural lineweights, exterior dimension strings (40'-0" × 28'-0"), room-by-room callouts, door swing arcs, and window schedules, plus instant browser printing for contractor bidding and preliminary municipal zoning review.