A 12x20 shed costs about $12,100 at US-average prices for a custom, unfinished inside build ($8,500 to $15,700), or $50 per square foot for 240 sq ft.
A 12x20 shed is 240 square feet, a full workshop or studio, and the first size in this set that is over the 200 sq ft permit-free limit of the model code.
12x20 shed cost by build grade
Per-square-foot prices from Fixr's storage shed guide (March 6, 2024), multiplied by the 240 sq ft floor area, at US averages. The spread around each typical figure is this site's assumption where the source gives one number, and the sourced range where it gives two.
| Build | What you get | Materials only | Built by a contractor | Crew days |
|---|---|---|---|---|
| Kit shed | Prefab kit you assemble on a prepared base | $2,200 to $4,000 | $4,300 to $7,900 (typical $6,100) | 2.5 |
| Custom, unfinished inside | Site-built wood frame, siding, shingles, bare interior | $4,300 to $7,900 | $8,500 to $15,700 (typical $12,100) | 5.5 |
| Custom, finished interior | Insulated, drywalled and wired, for a workshop or office | $12,100 to $24,000 | $24,000 to $48,000 (typical $36,000) | 16 |
Labor is taken as 50 percent of the price (Fixr's custom 10×12 example is about half), so materials-only figures drop that share. The permit is included where your town is likely to ask for one: from $100 (Fixr).
Framing and material list for a 12x20 shed
The quantities assume 8 ft walls, 2×4 studs 16 in on center, a 4/12 roof on 2×6 rafters at 24 in on center, one 6 ft double door and 2 3×3 ft windows, on a 4 in compacted gravel pad with pressure-treated skids. Studs run 84 pieces with corners, kings, jacks and cripples; the roof is 288 sq ft including overhangs.
| Item | Quantity | Detail |
|---|---|---|
| Compacted gravel base | 4 cu yd | 4 in deep, 14 × 22 ft (1 ft past each wall) |
| 4×6 skids, ground-contact treated | 4 pcs | 20 ft, 4 skids no more than 4 ft apart |
| 2×6 floor joists | 16 pcs | 12 ft, cut to 12 ft, 16 in on center |
| 2×6 rim boards | 2 pcs | 20 ft |
| ¾ in tongue-and-groove plywood, 4×8 | 9 sheets | floor deck, 10% extra |
| 2×4 studs, 91.5 in | 84 pcs | 16 in on center with corners, kings, jacks and cripples for 3 openings |
| 2×4 plates, 20 ft | 12 pcs | one bottom plate and a doubled top plate on every wall |
| Header stock, 2-ply 2×8 | 4 pcs | about 3 ft each; confirm the size against a header span table or use an LVL |
| Header stock, 2-ply 2×8 | 2 pcs | about 6 ft each; confirm the size against a header span table or use an LVL |
| 7/16 in OSB wall sheathing, 4×8 | 16 sheets | full sheets before subtracting openings |
| Siding, T1-11 or lap siding | 564 sq ft | gross wall area plus 10%, before openings and gable triangles |
| 6 ft double shed door | 1 pcs | |
| 3×3 ft windows | 2 pcs | |
| 2×6 rafters | 22 pcs | 8 ft, 6.8 ft cut length, 24 in on center |
| 2×8 ridge board | 2 pcs | 21 ft |
| 7/16 in OSB roof sheathing, 4×8 | 10 sheets | 288 sq ft of roof plus 10% |
| Synthetic, 10 sq roll (TAMKO Synthetic Guard) | 1 rolls | |
| Architectural shingles | 10 bundles | 3.2 squares, 3 bundles a square, 10% extra |
| Starter strip shingles | 1 bundles | |
| Hip and ridge caps | 1 bundles | |
| Drip edge, 10 ft | 7 pcs | eaves and rakes |
These are ordering quantities with 10 percent waste on sheets and shingles, not a plan set. The stud calculator and framing calculator handle a different wall, and the roofing calculator prices the roof covering separately.
Labor and time
At $70 an hour for each of two builders working eight hours ($1,100 a day), labor of $6,000 is about 5.5 days of crew work. Fixr counts labor for a custom shed at roughly half of the price, so a kit is the fast option when time matters.
Does a 12x20 shed need a permit?
IRC 2024 R105.2 exempts one-story detached accessory structures up to 200 sq ft. At 240 sq ft a 12x20 shed is over that limit, so it needs a permit, along with the plan review and inspections that come with it. Setbacks, height limits and deed rules apply either way.
12x20 shed compared with other sizes
Stepping down to 12x16 saves 48 sq ft and about $2,400.
Next steps for a 12x20 shed
- Count studs, plates and sheathing with the stud calculator and plywood calculator.
- Cover the roof with the roofing calculator or the shingle calculator.
- Other sizes and types are grouped under cost calculators.