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ShedCalc
240 sq ft · free & unbiased

12×20 Shed Material List

A 12×20 is a large shed by any measure — 240 square feet that edges toward small-garage territory. It's the size to consider when you're storing vehicles, trailers, or running a workshop that needs real floor space.

How much lumber for a 12×20 shed?

Here's a shopping-ready estimate for a standard 12×20 build — 8 ft walls, studs 16" on-centre, 3-stud corners, one door and a 4/12 gable roof — with a 10% waste factor already included.

2×4 boards

125

4×8 sheets

27

Roof area

253 sq ft

Wall & roof framing

  • 2×4 wall studs (8 ft)

    48 field studs (perimeter ÷ 16" spacing) + 12 corner studs (3-stud corners) + 4 for 1 door & 0 windows

    71 boards

  • 2×4 plates (12 ft)

    192 linear ft (bottom + double top plate) ÷ 12 ft

    18 boards

  • 2×4 roof rafters (8 ft)

    32 rafters (2 planes × rows at 16" spacing)

    36 boards

Sheet goods

  • Siding / wall sheathing (4×8)

    512 sq ft of wall ÷ 32 sq ft per sheet

    18 sheets

  • Roof sheathing (4×8)

    253 sq ft of roof ÷ 32 sq ft per sheet

    9 sheets

Roofing

  • Roof area

    footprint 240 sq ft × 1.054 slope factor

    253 sq ft

  • Shingle bundles (~3 / square)

    2.53 squares × 3 bundles

    9 bundles

How these numbers are worked out

  • Perimeter of 64 ft with studs at 16" on-centre.
  • 3-stud (California) corners at all 4 corners.
  • Openings framed explicitly: +4 studs per door, +6 per window (1 door, 0 windows).
  • Walls: one bottom plate + a double top plate (3 × perimeter of 2×4 stock).
  • Sheet goods are 4 ft × 8 ft (32 sq ft each).
  • Gable roof at 4/12 pitch → 1.054× the flat footprint.
  • Asphalt shingles at 3 bundles per 100 sq ft "square".
  • A 10% waste factor is added, then each quantity is rounded up.

Building a different spec?

Change the wall height, stud spacing, roof pitch, corners, doors, and windows — and copy or print the list — in the full calculator.

Open the Material Calculator

What fits in a 12×20 shed

Heavy storage and workshop use, including a vehicle or trailer.

  • A small vehicle, trailer, or multiple ride-on machines
  • A full workshop with benches and machinery
  • Bulk and long-term storage
  • Lumber racks and large tool storage

Tips for a 12×20 build

  • Wide double doors or a roll-up door are worth it at this size for vehicle and trailer access.
  • Expect a permit, a proper foundation, and setback rules — this is a substantial structure.

Questions

12×20 shed FAQ

Straight answers on materials, capacity, permits, and cost for a 12×20 shed.

How much lumber do I need for a 12×20 shed?
For a 12×20 shed with 8 ft walls, studs at 16 inches on-centre, 3-stud corners, one door and a 4/12 roof, this calculator estimates about 71 2×4 studs, 18 boards of 2×4 plate stock and 36 roof rafters, plus roughly 18 sheets of 4×8 siding, 9 sheets of roof sheathing and 9 bundles of shingles. Those figures already include a 10% waste allowance. Adjust the spacing, pitch or openings in the calculator to match your exact design.
What can you fit in a 12×20 shed?
A 12×20 shed gives you 240 square feet. It comfortably holds a small vehicle, trailer, or multiple ride-on machines, a full workshop with benches and machinery, bulk and long-term storage, lumber racks and large tool storage. Heavy storage and workshop use, including a vehicle or trailer.
Do I need a permit for a 12×20 shed?
It depends on where you live. At 240 square feet, a 12×20 shed is large enough that many areas require a building permit, but the rules also consider height, foundation, and how close the shed sits to property lines. Always confirm with your local building department before you start — thresholds vary from one place to the next.
How much does a 12×20 shed cost to build?
The material cost depends on your siding, roofing, foundation, and finishes, and labour varies widely by region — so a single figure would be misleading. Use the material list here as your starting quantities, add local prices, and treat the total as a planning estimate rather than a fixed quote.

Compare other shed sizes

Material lists for more common footprints.

4×6

24 sq ft

8×8

64 sq ft

8×10

80 sq ft

8×12

96 sq ft

10×10

100 sq ft

10×12

120 sq ft

See all shed sizes