How Big is a 20×20 Shed?

400
square feet
·
20×20
dimensions (ft)
·
Shed
category

What Does 20×20 Actually Look Like?

This shed matches the footprint of a large two-car garage or a small studio apartment. You could park four compact cars inside with walking space between them, or set up a complete automotive repair bay with lift equipment. The space equals roughly half a basketball court, giving you perspective on the substantial storage and work area this structure provides.

Picture a space large enough to park two full-size pickup trucks side by side with room for workbenches along the walls.

A 20×20 shed provides 400 square feet of storage space, making it one of the largest residential outbuildings you can construct without special permits in most areas. This barn-scale structure offers enough room for multiple vehicles, extensive workshop operations, or commercial-grade storage needs. The square footprint maximizes usable space while maintaining structural efficiency, with 20-foot spans requiring engineered trusses or beam systems for proper support.

At this size, you're essentially building a small warehouse that can accommodate riding mowers, ATVs, boats, and full woodworking shops with room to move around comfortably. The 400 square feet rivals many studio apartments and provides serious utility for property owners with substantial storage or workspace requirements. Construction complexity increases significantly at this scale, requiring concrete foundations, proper electrical systems, and potentially HVAC considerations depending on intended use.

What Fits in 20×20?

  • Two riding mowers plus full landscaping equipment collection
  • Complete woodworking shop with table saw, planer, and lumber storage
  • RV or large boat with trailer
  • Four ATVs or motorcycles with maintenance area
  • Commercial lawn care business equipment and supplies
  • Full automotive workshop with car lift
  • Seasonal storage for multiple households

Build vs Buy: 20×20 Shed

DIY Build

$8,000–$15,000

Requires advanced framing skills and engineered plans

Pre-fab Kit

$12,000–$18,000

Limited kit options at this size, most require custom ordering

Custom Built

$18,000–$35,000

Professional construction recommended for structural integrity

20×20 Shed Materials List

Material Quantity Est. Cost
Engineered roof trusses (24" OC) 11 pieces $2,200
Pressure treated sill plates (2×6×20') 8 pieces $320
Wall studs (2×4×8') 45 pieces $360
Plywood sheathing (4×8 sheets) 28 sheets $1,400
Metal roofing (29 gauge) 500 sq ft $800
Concrete for slab (4" thick) 15 cubic yards $1,800
Overhead garage doors (8×8) 2 units $1,200
Electrical service panel and wiring 1 system $800

How Much Does a 20×20 Shed Cost?

Expect to pay between $8,000 and $35,000 to build. Building yourself is cheapest; prefab kits land in the middle; custom built is most expensive.

Common Uses for 20×20

Equipment storage for landscaping businesses Serious hobby workshops and maker spaces RV and boat storage facilities Agricultural equipment housing Commercial inventory storage Multi-vehicle parking and maintenance

Pro Tips

  • Install double doors (16-foot opening) on at least one side to accommodate large equipment and vehicles without tight maneuvering
  • Plan electrical service during construction - running 220V service for welders or large tools is much easier before walls are closed
  • Consider clear-span trusses to eliminate interior support posts, maximizing usable floor space for large equipment storage

Frequently Asked Questions

Do I need a permit for a 20×20 shed?
Most jurisdictions require building permits for structures over 200 square feet, so yes, you'll need permits. Many areas also require engineered plans for spans over 16 feet. Check setback requirements, as larger sheds often need to be positioned further from property lines.
What foundation is required for this size shed?
A 400 square foot shed typically requires a concrete slab foundation or concrete pier system. Simple gravel pads aren't adequate for this size structure. The foundation should be at least 4 inches thick with proper vapor barriers and reinforcement.
How much does it cost to build a 20×20 shed?
Expect $8,000-$25,000 depending on materials and features. Basic DIY construction runs $8,000-$12,000, while custom builds with electrical, insulation, and premium materials can reach $25,000 or more.

Bear With Me

The strangest part wasn't the size — it was what we found inside. My brother called me to help clean out Dad's shed after the funeral. I remembered it as cramped, cluttered with garden tools and paint cans. A place where Dad puttered, fixing broken things. But standing in the doorway, I felt dwarfed. Two riding mowers dominated the center like sleeping beasts. A complete woodworking shop lined the walls — table saw, planer, lumber sorted by species and thickness. Professional-grade landscaping equipment I'd never seen before. "This can't be right," I whispered, pacing the perimeter. Twenty feet. Then twenty more. Four hundred square feet of a life I never knew existed. My brother picked up a trophy from the workbench. "First Place, County Fair, 2018." Then another. And another. All those weekends Dad said he was "just tinkering." All those times I dismissed his projects as amateur hour. The careful distance I'd kept from his "little hobbies." I ran my fingers along a hand-carved jewelry box, smooth as silk. The nameplate read "For Sarah's Wedding Day — Love, Dad." I never got married. Never gave him the chance to present it. We stood there surrounded by his hidden magnificence, two strangers in our father's secret cathedral.

sister Spectacle The Corrupted Memory The strangest part wasn't the size — it was what we found inside.

Quick Reference: 20×20 in Different Units

400
sq feet
57,600
sq inches
44.4
sq yards
37.2
sq meters