Skip to content

Free shed plan

16x20 Shed Plans: Gable Roof

A wide shed, big enough for a small workshop and storage together. The long members are spliced over supports from 16 ft boards.

sq ft
320
boards
174
sheets
45
offcut
5.3%
Change the size or options

Free, no sign-up. The PDF is generated in your browser.

Need another size? The shed designer gives you the free summary for any size, and the full builder's plan with every cut is $29.

16 ft wide by 20 ft deep, 6/12 gable roof, about 12' 9-3/8" to the peak.

Specifications

Footprint16' wide x 20' deep (320 sq ft)
RoofGable, 6/12 pitch, 6" eaves
Wall height7' 4-3/4" to top of plates
Overall heightabout 12' 9-3/8" from grade to peak
Framing2x4 walls at 16" OC, 2x6 rafters at 16" OC, 2x6 joists at 16" OC
Foundation5 pressure-treated 4x6 skids on a gravel pad
Doordouble door, 48" x 78" on the front wall (rough opening)
Windows3 x 24" x 24" rough opening
Longest board16 ft, longer members spliced over supports
Design snow load30 psf

Notes on this design

Where the long members are spliced

  • Left side wall: plates spliced over a stud at 105-3/4", cap plate at 160" from the left end.
  • Right side wall: plates spliced over a stud at 105-3/4", cap plate at 160" from the left end.
  • Ridge board: joint centered on a rafter pair at 112" from the front.
  • Skids: butt joints at 112", 160" from the front, staggered from skid to skid, each with a 4 ft 2x6 splice plate on both faces.
  • Rim joists: joint centered on a joist at 112" from the front; double that joist.
  • Fascia: butt joints centered on a rafter tail at 112", with a 3/16" gap, sealed, and two nails each side of the joint.

Foundation and floor

5 pressure-treated 4x6 skids run front to back on a compacted gravel pad. The floor joists run across them, so no joist spans more than 47-1/8". See the foundation guide for leveling and squaring.

16' wide20' deepFRONT
Floor framing from above: 16 joists at 16" on center between two rim joists. Skids dashed.

Wall framing

Walls are drawn from the outside. The side walls run the full depth and carry the rafters; the front and back gable walls fit between them. The wall framing guide walks through layout and raising.

DOOR48" x 78"Header 2-2x668-1/2"116-1/2"0"11-3/4"27-3/4"43-3/4"59-3/4"123-3/4"139-3/4"155-3/4"171-3/4"183-1/2"15' 5" long, studs 84-1/4"7' 4-3/4"door head 78"
Front wall: 15' 5" long, 12 full studs at 84-1/4". Tick marks under the wall are stud positions from the left end.

Front wall: layout marks

Marked from the left end of the bottom plate as drawn, heights from the subfloor.
Studs, left edge0", 11-3/4", 27-3/4", 43-3/4", 59-3/4", 65-1/2", 67", 116-1/2", 118", 123-3/4", 139-3/4", 155-3/4", 171-3/4", 183-1/2"
Door rough opening68-1/2" to 116-1/2" from the left end (48" wide)
Door header2-2x6, bottom at 78", top at 83-1/2" above the subfloor
WINDOW24" x 24"Header 2-2x680-1/2"104-1/2"0"11-3/4"27-3/4"43-3/4"59-3/4"75-3/4"123-3/4"139-3/4"155-3/4"171-3/4"183-1/2"15' 5" long, studs 84-1/4"7' 4-3/4"sill 54"window head 78"
Back wall: 15' 5" long, 14 full studs at 84-1/4". Tick marks under the wall are stud positions from the left end.

Back wall: layout marks

Marked from the left end of the bottom plate as drawn, heights from the subfloor.
Studs, left edge0", 11-3/4", 27-3/4", 43-3/4", 59-3/4", 75-3/4", 77-1/2", 79", 104-1/2", 106", 107-3/4", 123-3/4", 139-3/4", 155-3/4", 171-3/4", 183-1/2"
Window rough opening80-1/2" to 104-1/2" from the left end (24" wide)
Window silltop of the rough sill at 54" above the subfloor
Window header2-2x6, bottom at 78", top at 83-1/2" above the subfloor
WINDOW24" x 24"Header 2-2x6108"132"0"15-1/4"31-1/4"47-1/4"63-1/4"79-1/4"95-1/4"143-1/4"159-1/4"175-1/4"191-1/4"207-1/4"223-1/4"238-1/2"20' long, studs 84-1/4"7' 4-3/4"sill 54"window head 78"
Left side wall: 20' long, 18 full studs at 84-1/4". Tick marks under the wall are stud positions from the left end.

Left side wall: layout marks

Marked from the left end of the bottom plate as drawn, heights from the subfloor.
Studs, left edge0", 1-1/2", 15-1/4", 31-1/4", 47-1/4", 63-1/4", 79-1/4", 95-1/4", 105", 106-1/2", 132", 133-1/2", 143-1/4", 159-1/4", 175-1/4", 191-1/4", 207-1/4", 223-1/4", 237", 238-1/2"
Window rough opening108" to 132" from the left end (24" wide)
Window silltop of the rough sill at 54" above the subfloor
Window header2-2x6, bottom at 78", top at 83-1/2" above the subfloor
WINDOW24" x 24"Header 2-2x6108"132"0"15-1/4"31-1/4"47-1/4"63-1/4"79-1/4"95-1/4"143-1/4"159-1/4"175-1/4"191-1/4"207-1/4"223-1/4"238-1/2"20' long, studs 84-1/4"7' 4-3/4"sill 54"window head 78"
Right side wall: 20' long, 18 full studs at 84-1/4". Tick marks under the wall are stud positions from the left end.

Right side wall: layout marks

Marked from the left end of the bottom plate as drawn, heights from the subfloor.
Studs, left edge0", 1-1/2", 15-1/4", 31-1/4", 47-1/4", 63-1/4", 79-1/4", 95-1/4", 105", 106-1/2", 132", 133-1/2", 143-1/4", 159-1/4", 175-1/4", 191-1/4", 207-1/4", 223-1/4", 237", 238-1/2"
Window rough opening108" to 132" from the left end (24" wide)
Window silltop of the rough sill at 54" above the subfloor
Window header2-2x6, bottom at 78", top at 83-1/2" above the subfloor

Roof framing

32 2x6 rafters at 16" on center, 6/12 pitch with a 6" eave. A 2x8 ridge board and a 2x4 rafter tie at every pair keep the walls from spreading. The rafter guide shows how to lay out the pattern.

113-3/16" along the edge, plumb cut to plumb cut101-1/4" horizontal run6" tailseat 3-1/2", heel 1-3/4"6/12 plumb cuts (26.6°)
Pattern rafter: 2x6 x 115-15/16" stock, 113-3/16" plumb cut to plumb cut, birdsmouth seat 3-1/2" with a 1-3/4" heel.

Span checks

MemberSizeSpanAllowedResult
Rafters2x67' 11-1/4"11' 11-1/8"bendingOK, 50% spare
Floor joists2x63' 11-1/8"8' 7-13/16"deflectionOK, 120% spare
Window header, left side wall2-2x62' 3"6' 2-3/4"bendingOK, 177% spare
Window header, right side wall2-2x62' 3"6' 2-3/4"bendingOK, 177% spare

Checked for Spruce-Pine-Fir No. 2 with NDS design values, 30 psf snow plus 10 psf dead load, L/180 deflection for rafters. Use a heavier snow load in the designer if your area needs it.

Shopping list

Lumber to buyQty
4x6 pressure-treated (ground contact)
8 ft2
10 ft3
12 ft3
16 ft2
2x6 pressure-treated (ground contact)
10 ft6
16 ft19
2x4 framing lumber
8 ft35
10 ft5
12 ft5
16 ft43
2x6 framing lumber
10 ft27
12 ft6
2x8 framing lumber
10 ft1
12 ft1
1x4 exterior trim board
8 ft8
12 ft4
1x6 exterior trim board
12 ft4
Sheets, roofing and hardwareBuy
Sheet goods
3/4" tongue-and-groove plywood subfloor, 4x8long edge across the joists, end joints staggered10 sheets
Panel siding (T1-11 or engineered wood), 4x8one panel covers the floor frame and the wall, no horizontal joint18 sheets
Panel siding for the gable ends, 4x8triangles nest; includes 15% for angled cuts3 sheets
7/16" OSB roof sheathing, 4x8use H-clips between rafters at unsupported edges14 sheets
Z-flashing for the horizontal siding joints, 10 ft pieces32' of horizontal joint at the top plate under the gables; leave a 3/8" gap above it4 pieces
Roofing
Asphalt shingles, 3 bundles per square3.80 squares plus 10% waste13 bundles
Starter strip shingles40 lin ft along the eaves, counted at 100 lin ft per bundle; check the label1 bundle
Hip and ridge cap shingles20 lin ft of ridge, counted at 20 lin ft per bundle; check the label1 bundle
Synthetic roof underlayment, 10-square roll4.4 squares with laps1 roll
Drip edge, 10 ft pieceseaves and rakes9 pieces
Fasteners and hardware
Framing nails, 16d common, 3-1/2" x 0.162"about 1,100 nails at about 47 per lb; counted joint by joint to the IRC fastening schedule (2 per stud end, 3 per joist end), 15% spare included24 lb
Toenail nails, 10d box, 3" x 0.128"about 900 nails at about 94 per lb; for the toenailed joints: rafters to plates and ridge, joists to skids, gable studs; 15% spare included10 lb
Galvanized siding nails, 2-1/2" (8d)about 1,600 nails at about 90 per lb; 6" on edges, 12" in the field18 lb
Roof sheathing nails, 2-1/2" (8d)about 850 nails at about 90 per lb; 6" on edges, 12" in the field10 lb
Exterior screws for the subfloor, 2"about 500 screws at about 100 per lb; about 50 per sheet5 lb
Rafter-to-plate connectors (hurricane ties)one at every rafter bearing, fixed with the nails its label calls for32
Roofing nails, 1-1/4"about 1,350 nails at about 140 per lb; 4 per shingle, about 320 per square10 lb
Exterior screws for splice plates, 3"80 screws in boxes of 100, 8 per plate1 box
Construction adhesive (subfloor)one tube per 2 sheets5 tubes
Shed ground anchorsone near each corner; check local wind rules4

Lumber-yard takeoff

The whole shopping list on one printed page, with a box to tick for each line at the yard.

16x20 Gable Shed plan: lumber-yard takeoff

16' x 20' gable, 6/12 roof. Tick each line as it goes on the cart. theshedplanner.com

Lumber

  • 24x6 pressure-treated (ground contact), 8 ft
  • 34x6 pressure-treated (ground contact), 10 ft
  • 34x6 pressure-treated (ground contact), 12 ft
  • 24x6 pressure-treated (ground contact), 16 ft
  • 62x6 pressure-treated (ground contact), 10 ft
  • 192x6 pressure-treated (ground contact), 16 ft
  • 352x4 framing lumber, 8 ft
  • 52x4 framing lumber, 10 ft
  • 52x4 framing lumber, 12 ft
  • 432x4 framing lumber, 16 ft
  • 272x6 framing lumber, 10 ft
  • 62x6 framing lumber, 12 ft
  • 12x8 framing lumber, 10 ft
  • 12x8 framing lumber, 12 ft
  • 81x4 exterior trim board, 8 ft
  • 41x4 exterior trim board, 12 ft
  • 41x6 exterior trim board, 12 ft

Sheet goods

  • 10 sheets3/4" tongue-and-groove plywood subfloor, 4x8
  • 18 sheetsPanel siding (T1-11 or engineered wood), 4x8
  • 3 sheetsPanel siding for the gable ends, 4x8
  • 14 sheets7/16" OSB roof sheathing, 4x8
  • 4 piecesZ-flashing for the horizontal siding joints, 10 ft pieces

Roofing

  • 13 bundlesAsphalt shingles, 3 bundles per square
  • 1 bundleStarter strip shingles
  • 1 bundleHip and ridge cap shingles
  • 1 rollSynthetic roof underlayment, 10-square roll
  • 9 piecesDrip edge, 10 ft pieces

Fasteners and hardware

  • 24 lbFraming nails, 16d common, 3-1/2" x 0.162"
  • 10 lbToenail nails, 10d box, 3" x 0.128"
  • 18 lbGalvanized siding nails, 2-1/2" (8d)
  • 10 lbRoof sheathing nails, 2-1/2" (8d)
  • 5 lbExterior screws for the subfloor, 2"
  • 32Rafter-to-plate connectors (hurricane ties)
  • 10 lbRoofing nails, 1-1/4"
  • 1 boxExterior screws for splice plates, 3"
  • 5 tubesConstruction adhesive (subfloor)
  • 4Shed ground anchors

Foundation

  • 1 rollLandscape fabric, enough to cover 18' x 22'

Site prep

  • 4.9 cu ydGravel base: compactable crushed stone, 4" pad 1 ft wider than the shed on every side, before compactionBagged at Home Depot, Hamilton Mill store (ZIP 30011), Sep 30, 2026: $1,714.55 (265 bags of 0.5 cu ft at $6.47). Bulk from a landscape or building supplier is typically cheaper: East Coast Lumber & Building Supply (East Hampstead, NH) listed 3/4 in crushed stone at $69.95 per cubic yard on Sep 30, 2026, delivered in loads of 3 to 8 yards. Site prep, not in the shed materials total.

Cut list

QtySizeLengthPiece
Front wall
22x476-1/2"Jack stud, door
22x651"Header ply, door (48" opening)
32x42-1/4"Cripple above door header
122x484-1/4"Stud
22x4185"Bottom and top plate
12x4192"Cap plate (second top plate)
22x46-5/8"Gable stud (long point)
22x414-5/8"Gable stud (long point)
22x422-5/8"Gable stud (long point)
22x430-5/8"Gable stud (long point)
22x438-5/8"Gable stud (long point)
12x445-7/8"Gable stud (long point)
Back wall
22x476-1/2"Jack stud, window
22x627"Header ply, window (24" opening)
12x42-1/4"Cripple above window header
12x424"Rough sill, window
12x451"Cripple below window sill
142x484-1/4"Stud
22x4185"Bottom and top plate
12x4192"Cap plate (second top plate)
22x46-5/8"Gable stud (long point)
22x414-5/8"Gable stud (long point)
22x422-5/8"Gable stud (long point)
22x430-5/8"Gable stud (long point)
22x438-5/8"Gable stud (long point)
12x445-7/8"Gable stud (long point)
Left side wall
22x476-1/2"Jack stud, window
22x627"Header ply, window (24" opening)
22x42-1/4"Cripple above window header
12x424"Rough sill, window
22x451"Cripple below window sill
182x484-1/4"Studincludes 2 corner backer studs
22x4105-3/4"Bottom and top platespliced: joints centered on a stud
22x4134-1/4"Bottom and top platespliced: joints centered on a stud
12x4156-1/2"Cap plate (second top plate)joints at least 4 ft from the top plate joints
12x476-1/2"Cap plate (second top plate)joints at least 4 ft from the top plate joints
Right side wall
22x476-1/2"Jack stud, window
22x627"Header ply, window (24" opening)
22x42-1/4"Cripple above window header
12x424"Rough sill, window
22x451"Cripple below window sill
182x484-1/4"Studincludes 2 corner backer studs
22x4105-3/4"Bottom and top platespliced: joints centered on a stud
22x4134-1/4"Bottom and top platespliced: joints centered on a stud
12x4156-1/2"Cap plate (second top plate)joints at least 4 ft from the top plate joints
12x476-1/2"Cap plate (second top plate)joints at least 4 ft from the top plate joints
Roof
322x6115-15/16"Common rafter
12x8112"Ridge boardspliced: joint centered on a rafter pair
12x8128"Ridge boardspliced: joint centered on a rafter pair
162x4192"Rafter tie (ends cut to roof slope)
Floor
34x6 PT112"Skid (runs front to back)spliced: joints staggered from skid to skid
34x6 PT128"Skid (runs front to back)spliced: joints staggered from skid to skid
102x6 PT48"Skid splice plate (one each side of a joint)
24x6 PT160"Skid (runs front to back)spliced: joints staggered from skid to skid
24x6 PT80"Skid (runs front to back)spliced: joints staggered from skid to skid
162x6 PT189"Floor joist
22x6 PT112"Rim joist (sides)spliced: joint centered on a doubled joist
22x6 PT128"Rim joist (sides)spliced: joint centered on a doubled joist
12x6 PT189"Doubled joist at a rim joint
Trim
81x496"Corner trim board
21x6112"Fascia board (eaves)spliced: butt joint over a rafter tail, 3/16" gap, sealed
21x6128"Fascia board (eaves)spliced: butt joint over a rafter tail, 3/16" gap, sealed
41x4114-1/16"Rake trim board

Build it in 7 steps

  1. 1

    Check permits and pick the site

    Confirm what your building department and zoning rules require for a 320 sq ft shed, then call 811 before you dig. Read the guide

  2. 2

    Build the foundation

    Level a gravel pad 1 ft wider than the shed and set 5 pressure-treated 4x6 skids 47-1/8" on center. Read the guide

  3. 3

    Frame the floor

    Two 20' rim joists and 16 joists at 189", 16" on center, squared by the diagonals and covered with 3/4" tongue-and-groove plywood.

  4. 4

    Frame and raise the walls

    Build each wall flat with 84-1/4" studs, headers over the openings and a double top plate. Raise, plumb and brace. Read the guide

  5. 5

    Cut and set the rafters

    Make one pattern 2x6 rafter, 113-3/16" plumb cut to plumb cut, test it, then cut 31 more. Set the 2x8 ridge and add a 2x4 rafter tie at every pair. Read the guide

  6. 6

    Sheathe and roof

    Nail 14 sheets of 7/16" OSB, add drip edge and underlayment, then shingles.

  7. 7

    Side and trim

    Hang the panel siding, then the corner boards, fascia and rake trim. Fit the doors and windows and seal every cut edge.

Guides for this build

Other free shed plans