20×20 Shed Material List
At 400 square feet, a 20×20 is less a shed than a small outbuilding — a square footprint roughly the size of a two-car garage. This is the size you reach for when the project is a real workshop, serious equipment storage, or a building you expect to spend proper time in.
How much lumber for a 20×20 shed?
Here's a shopping-ready estimate for a standard 20×20 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
142
4×8 sheets
37
Roof area
422 sq ft
Wall & roof framing
2×4 wall studs (8 ft)
60 field studs (perimeter ÷ 16" spacing) + 12 corner studs (3-stud corners) + 4 for 1 door & 0 windows
84 boards
2×4 plates (12 ft)
240 linear ft (bottom + double top plate) ÷ 12 ft
22 boards
2×4 roof rafters (12 ft)
32 rafters (2 planes × rows at 16" spacing)
36 boards
Sheet goods
Siding / wall sheathing (4×8)
640 sq ft of wall ÷ 32 sq ft per sheet
22 sheets
Roof sheathing (4×8)
422 sq ft of roof ÷ 32 sq ft per sheet
15 sheets
Roofing
Roof area
footprint 400 sq ft × 1.054 slope factor
422 sq ft
Shingle bundles (~3 / square)
4.22 squares × 3 bundles
14 bundles
How these numbers are worked out
- Perimeter of 80 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 CalculatorWhat fits in a 20×20 shed
Garage-scale storage and a full working workshop.
- Two vehicles, or one vehicle plus a full workshop
- Stationary tools with room to feed long stock through
- A dedicated assembly or staging area
- Racking for lumber, tyres, and bulk storage
Tips for a 20×20 build
- A square 400 sq ft span is wide — the roof structure and header sizing matter far more here than on a small shed, so get the framing checked if you're unsure.
- Expect the full permit process, engineered foundation, and setback review; at this scale many areas treat the build much like a garage.
Questions
20×20 shed FAQ
Straight answers on materials, capacity, permits, and cost for a 20×20 shed.
How much lumber do I need for a 20×20 shed?
What can you fit in a 20×20 shed?
Do I need a permit for a 20×20 shed?
How much does a 20×20 shed cost to build?
Compare other shed sizes
Material lists for more common footprints.