Backyard ADU / Granny FlatPlan HG-1047
322 Sq Ft (16x20) 1 Bed 1 Bath Backyard ADU / Granny Flat Floor Plan
322
Sq Ft
1
Beds
1
Baths
16x20
Shell
Shell Est: $15,000
16' × 20' Shell • 3 Floor Plans
16' × 20' Floor Plans (320 Sq Ft Base)
Compare 3 build-ready ways to configure a 16-foot by 20-foot structure—including all-living homes, shop-house splits, and 2-story lofts.
3 Plans
3 Plans
Tiny Home on FoundationPlan HG-1048
322 Sq Ft (16x20) 1 Bed 1 Bath Tiny Home on Foundation Floor Plan
322
Sq Ft
1
Beds
1
Baths
16x20
Shell
Shell Est: $15,500
Container HomePlan HG-1049
322 Sq Ft (16x20) 1 Bed 1 Bath Container Home Floor Plan
322
Sq Ft
1
Beds
1
Baths
16x20
Shell
Shell Est: $11,500
16' × 20' Build Cost Guide, Nearby Sizes & FAQs
Slab takeoff, framing span notes, and comparable footprint sizes
16' × 20' Build Cost Guide, Nearby Sizes & FAQs
Slab takeoff, framing span notes, and comparable footprint sizes
Nearby Footprint Sizes:12'×24' (288 sf)12'×28' (336 sf)12'×32' (384 sf)14'×24' (336 sf)14'×28' (392 sf)14'×32' (448 sf)14'×36' (504 sf)14'×40' (560 sf)
16' Clear-Span Truss & Slab Engineering
A 16' × 20' rectangular building envelope (320 sq ft base area, 72 linear feet of exterior wall) is one of the most cost-effective structural modules in residential construction. Because the 16-foot width can be spanned by single-piece prefabricated wood roof trusses or cold-formed steel rafters, interior walls are non-load-bearing—allowing complete flexibility between open great rooms, split bedroom wings, and drive-in garage bays.
Material Takeoff Baseline (8 Cu. Yds. Concrete / 4 Roof Squares)
Every 4-corner 16x20 layout eliminates expensive hip-and-valley roof framing and minimizes foundation form corners. Builders typically budget 8 cubic yards of 4,000-PSI concrete for the monolithic slab, 61 exterior 2x6 studs (or 9 laminated post-frame columns at 8' o.c.), and 4 squares of standing-seam or ribbed metal roofing.
How many bedrooms and bathrooms fit inside a 16x20 (320 sq ft) floor plan?
A 16' × 20' building footprint (320 sq ft base area) comfortably supports 1 to 2 bedrooms and 1 bathroom in an open-concept ADU, tiny home, or cabin configuration. Browse all 3 vetted 16x20 floor plan variations above to compare room sizes.
How much concrete and roofing material does a 16x20 building require?
A 16' × 20' footprint has 72 linear feet of exterior perimeter wall. Pouring a 4-inch monolithic concrete slab with thickened perimeter grade beams requires approximately 8 cubic yards of ready-mix concrete. A standard gable roof with 18-inch overhangs requires roughly 4 roofing squares (400 sq ft of metal or shingle coverage).
What is the average cost to build a 16x20 house or barndominium?
Across our 3 engineered 16x20 blueprints, dried-in structural shell packages range from $9,600 to $15,360, while full turnkey construction averages $60,667 depending on whether the footprint is configured as all-living space or split between living quarters and an unheated shop bay.