20x20 Shed Material List

Quick Answer

A 20x20 gable shed with 8 ft walls, 16 inch on center framing, 4/12 roof pitch, pressure treated floor framing, OSB or plywood sheathing, a basic double door, and gravel foundation is an extremely large backyard structure. This size is commonly used as a full garage alternative, large workshop, vehicle storage building, or multi-use hobby space. The 20 ft span requires heavy structural framing beyond typical shed construction.

See all shed material lists by size

You will need:

• Very heavy pressure treated lumber for the floor system
• 2x4 wall framing
• 2x10 or larger roof framing for the wide span
• Extensive floor, wall, and roof sheathing
• Panel or lap siding
• Asphalt shingles and underlayment
• Reinforced double door framing
• Large quantities of fasteners and hardware

In 2026 pricing, expect a realistic total material cost of: $11,000 to $18,000

This assumes a gravel base and basic exterior finishes only.

Need a smaller option? See our 12x30 shed material list. Want a larger build? See our 14x30 shed material list.

Full Material List

Quantities assume 8 ft wall height, 16 inch on center spacing, and a standard double door on one wall.

Floor Framing

A 20 ft span requires very strong joists or additional supports.

Gravel Base

• 11 to 14 cubic yards of compacted 3/4 inch crushed gravel

Floor Frame (Pressure Treated)

Perimeter

• 2x12x20 PT – 4 (rim and band joists)

Floor Joists (16 inch OC across 20 ft span)

2x12 joists are minimum for heavy-duty use.

• 2x12x20 PT – 14 to 16

Many builders install a center beam to reduce span.

Floor Sheathing

• 3/4 inch tongue and groove plywood or OSB – 13 sheets

Fasteners

• Exterior-rated screws or galvanized framing nails
• Heavy-duty joist hangers strongly recommended

Wall Framing

Framed 16 inch on center.

• 2x4x8 studs
• 180 to 200 total
• Includes perimeter walls
• Additional studs for corners and door framing
• Waste allowance

Plates

• 2x4x20 – 12 (bottom plates and double top plates)

Splicing shorter boards over studs is common for long walls.

Double Door Framing

Typical opening: 60 to 72 inches wide.

• 2x12x8 – 2 (header material)
• 1/2 inch plywood spacer
• Additional jack and king studs included in stud count

Roof Framing

A 20 ft span requires heavy rafters and a strong ridge.

Rafters (4/12 pitch, 16 inch OC)

• 2x10x22 or 2x12x22 – 36 to 40

Approximately 18 to 20 rafter pairs.

Ridge Board

• 2x14x20 – 1

Collar Ties or Ceiling Joists

• 2x4x20 – 18 to 20

Sheathing

Large buildings require substantial sheet goods.

Wall Sheathing

• 7/16 inch OSB or plywood – 32 to 36 sheets

Panel siding may eliminate separate sheathing.

Roof Sheathing

• 7/16 inch OSB or plywood – 22 to 24 sheets

Siding

Panel siding is common for large sheds.

T1-11 or LP SmartSide Panels

• 32 to 36 sheets

Vinyl or lap siding systems require additional trim and backing.

Roofing

Underlayment

• 3 rolls synthetic underlayment

Drip Edge

• 14 to 16 pieces (10 ft lengths)

Shingles

• Approximately 5 to 5.5 squares
• 17 to 22 bundles depending on waste

Roofing Nails

• 18 to 20 lb box

Hardware and Fasteners

• 16d framing nails or structural screws
• 8d nails for sheathing
• Exterior construction screws
• Construction adhesive (8 to 10 tubes)
• Hurricane ties strongly recommended
• Heavy-duty hinges (3 per door)
• Exterior double-door latch or lockset
• Padlock hardware
• Flashing for door header

Estimated Cost Breakdown

Typical 2026 pricing ranges.

• Gravel Base: $600 to $1,200
• Pressure Treated Floor Framing: $2,200 to $3,800
• Wall Framing Lumber: $1,500 to $2,600
• Roof Framing Lumber: $1,900 to $3,200
• Sheathing (walls and roof): $2,400 to $3,800
• Siding: T1-11: $1,700 to $2,600; LP SmartSide: $3,000 to $4,800; Vinyl system: $4,000 to $6,500
• Roofing: $1,300 to $2,200
• Hardware and Fasteners: $500 to $900

Total Estimated Range

With basic panel siding: $11,000 to $14,000

With upgraded siding: $14,000 to $18,000

Costs increase dramatically due to:

• Very wide 20 ft span requiring heavy framing
• Large floor area (400 sq ft)
• Long wall runs with high stud counts
• Extensive roof coverage
• Reinforced door framing
• High material weight and volume
• Increased fastener usage
• Possible delivery surcharges

If you want exact cut diagrams, printable framing layouts, and step-by-step blueprints for this 20x20 shed, detailed plans eliminate guesswork and reduce lumber waste.

Get the Complete 20x20 Shed Plans Here

Tools Required

Standard framing tools plus equipment capable of handling very heavy materials.

Essential tools:

• Circular saw
• Miter saw
• Drill and impact driver
• Framing hammer
• 4 ft or longer level
• Speed square
• Tape measure
• Chalk line
• Multiple ladders
• Shovel and rake
• Plate compactor or heavy hand tamper

Helpful tools:

• Pneumatic framing nailer
• Roofing nailer
• Laser level
• Sawhorses
• Clamps

Assistance is required. Components are too heavy for solo construction.

Step-by-Step Build Overview

High-level sequence only.

• Prepare and compact gravel base across entire footprint.
• Build pressure treated floor frame and verify square.
• Install floor sheathing.
• Frame walls on the ground including double door opening.
• Raise walls with assistance, plumb, and brace securely.
• Install double top plates tying walls together.
• Install ridge board and rafters.
• Add collar ties or ceiling joists.
• Install roof sheathing.
• Install drip edge and underlayment.
• Install shingles.
• Install wall sheathing if required.
• Install siding.
• Build and hang double doors.
• Install trim and hardware.
• Frequent checks for level and square are critical on structures this large.

Common Mistakes

• Using undersized framing for the span. Leads to structural failure or sagging.
• Poor base preparation. Causes uneven settling across the building.
• Attempting construction without assistance. Heavy components are dangerous to handle alone.
• Underestimating materials. Causes delays and increased costs.
• Weak door framing. Leads to sagging or misalignment.
• Skipping structural connectors. Reduces resistance to wind loads.
• Not planning for delivery logistics. Materials are heavy and bulky.

Is It Worth Building Yourself?

DIY material cost: $11,000 to $18,000

Typical prebuilt 20x20 shed delivered in 2026: $18,000 to $35,000

DIY savings typically range from $7,000 to $17,000.

Consider:

• Construction time of roughly 8 to 14 days with help
• Significant material delivery logistics
• Structural accuracy requirements
• Likely permits and zoning requirements

For experienced DIY builders with assistance, building yourself can be financially worthwhile. If convenience, warranty, and speed are priorities, a prebuilt structure may be preferable.

Get Exact Cut Diagrams and Printable Plans

This material list provides realistic quantities and cost expectations for a 20x20 shed.

It does not include:

• Exact rafter angle calculations
• Detailed wall framing layouts
• Header engineering details
• Precise overhang measurements
• Optimized cut lists
• Printable construction diagrams

On structures of this size, mistakes can waste large amounts of material and time.

Detailed blueprints with exact measurements, framing layouts, and printable cut sheets simplify construction, reduce waste, and help ensure structural accuracy.

For large one-time builds, complete plans typically save more time and money than they cost by preventing errors and rework.

Get the Complete 20x20 Shed Plans Here