12x12 Lean-To Shed Material List: Lumber, Sheets, Hardware

Last updated October 14, 2026

A 12×12 lean-to shed material list on skids comes to 52 2x4s, 16 plain 2x6s (12 are 14 ft rafter stock), 12 treated 2x6s and 4 treated 4×4 skids. Sheets: 5 floor plywood, 7 OSB, 14 T1-11, plus 7 shingle bundles. Assumes an 80 in back wall, 115 1/8 in front wall and 3/12 roof.

Every count here comes from a full 3D layout of this exact shed, grouped by the board lengths the yard sells. A 12 ft deep lean-to is near the limit for 2×6 rafters, and each side wall has 10 studs of 10 different lengths. This list is for a freestanding shed with a shingle roof; it does not cover a metal roof, a ledger against a house or ground anchors. For the house-wall version, see building a lean-to shed against a house.

What this 12×12 lean-to list assumes

This list is for a shed 12 ft deep and 12 ft wide, with 144 sq ft of floor. The roof slopes front to back, so the front wall with the door is the tall one. These are its settings:

• Walls: the back (low) wall is 80 in tall and the front (high) wall is 115 1/8 in, both including the bottom plate and double top plate. Back studs are 6′ 3 1/2″ and front studs 9′ 2 5/8″.
• Roof: 3/12 pitch (about 14 degrees), 2×6 rafters with a birdsmouth on both walls, 8 in overhangs front and back, 4 in rakes. The roof is 152 in long by about 165 in down the slope, roughly 174 sq ft.
• Height: about 11 ft 1 in tall overall at the high front edge, measured from the bottom of the skids.
• Spacing: studs, floor joists and rafters at 16 in on center.
• Floor: four pressure-treated 4×4 skids on a crushed stone pad, 2×6 joists across the 12 ft depth, 3/4 in tongue and groove plywood.
• Loads: the 2×6 rafters span 137 in against a 143 in limit (SPF #2 at 16 in, 30 psf ground snow). In heavier snow country, check your local permit office for your snow load.
• Openings: a 60 in double door in the front wall and one 36 x 36 in window in the back wall.

Shopping list by stage: the full 12×12 lean-to shed material list

Lumber sizes are nominal. A 2×4 measures about 1 1/2 x 3 1/2 in and a 2×6 about 1 1/2 x 5 1/2 in, as the American Wood Council explains. Check the grade stamp on plywood and OSB; the APA trademark guide shows how to read it.

Floor

Item	Qty	Used for
Pressure-treated 4×4 x 12 ft	4	Skids
Pressure-treated 2×6 x 12 ft	12	10 floor joists and 2 rim joists
3/4 in T&G plywood, 4×8 sheet	5	Floor decking
Crushed stone 3/4 in, loose	3.0 cu yd	Gravel pad
Deck screws 2 in (or 6d ring-shank nails)	4 lb	Decking

The 1 1/2 in decking filler strip along one rim is ripped from one of the 1×4 x 14 ft boards listed under siding and trim, so it adds nothing to the order. Ask for treated lumber rated for ground contact for the skids, rims and joists; the tag on each board says which rating it has.

Walls

Item	Qty	Used for
2×4 x 8 ft	13	Shorter side-wall studs, back sill and lower cripples, lookout blocks
2×4 x 10 ft	21	Front wall studs, front cripples, taller side-wall studs
2×4 x 12 ft	11	Front and back plates and cap plates, side-wall plates, sloped top plates, back window trimmers
2×4 x 14 ft	7	Back wall studs (two per board), front door trimmers
2×8 x 12 ft	1	Door header
2×6 x 8 ft	2	Window header, some rafter blocking
Strap ties (twist straps)	4	Lean-to wall corners
Temporary braces 2×4 x 12 ft	8	Wall bracing, reused later
2×4 stakes, 24 in	8	Brace stakes, 17 to 23 3/4 in, cut from offcuts

The two header filler strips of 1/2 in plywood are ripped from the soffit sheet, so buy that sheet with the wall lumber. With the 8 braces, the truck carries 60 2x4s in all.

Roof

Item	Qty	Used for
2×6 x 14 ft, SPF #2 or better	12	10 rafters and 2 fly rafters
2×6 x 10 ft	2	Blocking between rafters over each wall
Hurricane ties, H2.5A type or equal	20	Rafter to plate, both walls
7/16 in OSB, 4×8 sheet	7	Roof sheathing
15 lb felt, 400 sq ft roll	1	Underlayment, laid double below 4/12
3-tab shingles, 26 per bundle	7 bundles	Roof and starter course
Drip edge, 10 ft	6	Eaves and rakes
Roofing nails 1 1/4 in galvanized	6 lb	Shingles
Roofing cap nails 1 in	1 lb	Felt
Roofing cement, 10 oz tube	2	Roofing

Siding and trim

Item	Qty	Used for
5/8 in T1-11, 4×10 sheet	3	Front (high) wall
5/8 in T1-11, 4×8 sheet	3	Back (low) wall
5/8 in T1-11, 4×10 / 4×9 / 4×8 sheet	2 / 2 / 2	Sloped side walls
5/8 in T1-11, 4×8 sheet	2	Door leaves (one per leaf)
1/2 in plywood, 4×8 sheet	1	Eave soffit and header fillers
1×8 x 14 ft	2	Eave fascia
1×8 x 16 ft	2	Rake fascia
1×4 x 14 ft	7	Back corner trim, door casing sides, stiles, Z braces, decking filler
1×4 x 12 ft	1	Door rails
1×4 x 10 ft	4	Front corner trim
1×4 x 8 ft	3	Door head casing, window casing
1×2 x 8 ft	2	Door stop and astragal
Drip cap, 10 ft	1	Over the door and window head casings
Insect screen, 2 ft x 25 ft	1 roll	Gaps at the eaves and soffit (the list has no roof or gable vents)
Exterior paint and primer in one	5 gal	Two coats, about 546 sq ft each
Exterior caulk	3 tubes	Trim

Hardware and window

Item	Qty
Framing nails 3 1/2 in (16d), hot-dip galvanized	22 lb
Siding nails 2 1/2 in (8d), hot-dip galvanized	12 lb
Sheathing nails 2 1/2 in (8d) for OSB	6 lb
Connector nails 1 1/2 in for ties and straps	2 lb
Construction adhesive, 10 oz tube	7
T-strap door hinges	6
Door handle and latch set	1
Barrel bolts for the fixed leaf	2
Exterior screws 1 1/4 in (door frame to T1-11)	1 lb
Exterior screws 2 1/2 in (hinge straps into framing)	1 box
Prefabricated window, 36 x 36 in rough opening	1
Flashing tape 4 in	1 roll
Wood shims	1 bundle

Cut list highlights

Most of the 12×12 lean-to cut list is square cuts: 10 front studs at 9′ 2 5/8″, 12 back studs at 6′ 3 1/2″, 10 floor joists at 11′ 9″ and four skids at 12′ 0″. The parts below have angled cuts or a different length each time: a pattern cut wrong spreads to every copy, and a misread length ruins a board. Dry-fit the first of each part on your own frame before cutting the rest.

Part	Lumber	Cut length	Qty
Rafter (board length)	2×6	13′ 10 1/4″	10
Fly rafter (rake)	2×6	13′ 10 1/4″	2
Side wall sloped top plate	2×4	11′ 9 1/8″	2
Side wall bottom plate	2×4	11′ 4 7/8″	2
Left wall studs	2×4	6′ 5 3/8″ to 9′ 3 1/8″	10, all different
Right wall studs	2×4	9′ 3 1/4″ down to 6′ 5 3/8″	10, all different
Door header (2×8 doubled + 1/2 ply)	2×8	5′ 3″	2
Door trimmer	2×4	6′ 4 1/2″	2
Cripple over the door	2×4	2′ 2 7/8″	4
Window header (2×6 doubled + 1/2 ply)	2×6	3′ 3″	2
Window trimmer	2×4	5′ 10″	2
Blocking between rafters	2×6	1′ 1 3/4″ and 1′ 2 1/2″	4 and 14
Lookout block (rake overhang)	2×4	2 1/2″	16
Eave fascia	1×8	12′ 8″	2
Rake fascia (tip to tip)	1×8	14′ 0 1/4″	2
Front corner trim, side face (slope cut)	1×4	9′ 8 3/4″	2
Back corner trim, side face (slope cut)	1×4	6′ 9 3/8″	2

Rafters. The 13′ 10 1/4″ figure is the board each rafter needs, measured corner to corner. Along the top edge it is about 13′ 8 15/16″, including both 8 in overhangs. Plumb cuts are at about 14 degrees (3/12).

Each rafter gets two birdsmouths, one on each wall, with a 3 1/2 in seat that notches under 1 in into the 2×6, well inside the one-third rule. Cut one pattern rafter, test it on both walls, then trace the other 9. The 2 fly rafters sit on the lookout blocks and get no birdsmouth.

Side wall studs. Each side wall has 10 studs under a sloped top plate. The steps are 4 in except at the ends. Every length is the long point, from the top of the bottom plate to the underside of the sloped plate.

The left wall, listed from the back corner, runs 6′ 5 3/8″, 6′ 8 1/4″, 7′ 0 1/4″, 7′ 4 1/4″, 7′ 8 1/4″, 8′ 0 1/4″, 8′ 4 1/4″, 8′ 8 1/4″, 9′ 0 1/4″ and 9′ 3 1/8″. The right wall, listed from the front corner, runs 9′ 3 1/4″, 9′ 0 1/4″, 8′ 8 1/4″, 8′ 4 1/4″, 8′ 0 1/4″, 7′ 8 1/4″, 7′ 4 1/4″, 7′ 0 1/4″, 6′ 8 1/4″ and 6′ 5 3/8″.

Both walls slope the same way. Read from the back corner, the two lists match stud for stud except the front-corner stud, which is 1/8 in longer on the right. Mark each stud with its wall and position as you cut it. Cut the top of each stud at the roof angle (3 on a speed square, about 14 degrees) and check the first one against the plate.

Headers. The 60 in door gets a doubled 2×8 header with a 1/2 in plywood filler on 6′ 4 1/2″ trimmers. The front wall is tall, so the four cripples above the header are 2′ 2 7/8″, far longer than the 6 1/4″ cripples on a 12×12 gable. The back window header is a doubled 2×6 on 5′ 10″ trimmers, and it fills the space right up to the plates, so there are no cripples above it. Below the window go a 3′ 0″ sill and two 2′ 8 1/2″ cripples.

Plates. The front and back plates and cap plates run the full 12′ 0″. Each side wall has an 11′ 4 7/8″ bottom plate and a single 11′ 9 1/8″ sloped top plate between the front and back walls. The 4 twist straps tie the lean-to wall corners together.

Gable vs lean-to: what changes

The same 12×12 footprint run as a gable at 6/12 (94 1/2 in walls, door in the front, a window in each side wall) keeps the floor and changes almost everything above it. Our 12×12 shed material list covers the gable version in full.

Item	Lean-to (3/12)	Gable (6/12)
Rafters	10 2×6 at 13′ 10 1/4″ + 2 fly	20 2×4 at 7′ 6 3/8″ + 4 fly
Ridge board	None	2×6, cut 12′ 8″
Rafter ties and collar ties	None (no ridge, no outward thrust)	8 rafter ties + 4 collar ties
Wall studs	9′ 2 5/8″ front, 6′ 3 1/2″ back, stepped sides	7′ 6″ on all four walls
2×4 framing boards (plus 8 braces in both)	52	106
2×6 boards (not treated)	16	3
T1-11 sheets	14: five 4×10, two 4×9, seven 4×8	16, all 4×8
Roof OSB sheets	7	7
Shingle bundles	7	8 (incl. ridge cap)
Felt	1 roll, laid double	1 roll, single
Fascia	1×8	1×6
Framing nails	22 lb	31 lb
Windows	1	2
Extra hardware	4 twist straps	2 gable vents, 3 Z-flashing
Floor (skids, joists, decking)	4, 10, 5 sheets	4, 10, 5 sheets

The lean-to needs 54 fewer 2x4s and no ridge or gable triangles. In exchange it buys 13 more plain 2x6s, a double layer of felt, and 7 of its 14 siding sheets are 4×10 or 4×9 instead of 4×8. A lean-to sends all its roof water off the back edge, so keep that side clear of fences and paths. Our gable vs lean-to vs hip roof comparison covers the trade-offs beyond lumber.

Where the waste goes

Buying by stock length means every cut leaves an offcut. Here is where the scraps on a 12×12 lean-to come from:

• Rafters: 13′ 10 1/4″ from a 14 ft 2×6 leaves only about 1 3/4 in. There is no room for a bad end, so pick straight boards with square, uncracked ends, and buy one spare if your yard’s stock is rough.
• Back studs: two 6′ 3 1/2″ studs come out of each 14 ft 2×4, leaving about 17 in. The two door trimmers pair up in one more 14 ft board.
• Front studs: 9′ 2 5/8″ from a 10 ft board leaves about 9 3/8 in each, too short for a brace stake. Take the eight stakes from the longest scraps instead: about 23 3/4 in from the two 8′ 0 1/4″ side studs, up to about 18 5/8 in from the 6′ 5 3/8″ ones, and 17 in from the back-stud pairs. A stake of 17 in or more still holds a temporary brace in firm ground.
• Side studs: the short ones come from 8 ft boards and the tall ones from 10 ft boards, so the offcuts vary from a few inches to over a foot.
• Floor joists: 11′ 9″ from a 12 ft board leaves 3 in for squaring the ends.
• Fascia: each 12′ 8″ eave fascia leaves about 16 in of a 14 ft 1×8. Each 14′ 0 1/4″ rake fascia comes from a 16 ft 1×8 and leaves about 2 ft.
• No spares: the counts are exact. Add a few 2×4 x 8 ft if you expect to reject warped or split boards.

The longest boards on this list are the two 16 ft 1×8 rake fascias; all framing tops out at 14 ft. Either one hangs well past a pickup bed, so flag the overhang or ask the yard to deliver.

Common mistakes

• Buying 4×8 siding for the front wall. The front wall alone is 115 1/8 in tall, over 9 1/2 ft, so the front and part of each side take 4×10 or 4×9 T1-11 sheets. Check that your yard stocks them before you order.
• Downsizing or spreading the rafters. At 137 in the 2×6 rafters already use most of their 143 in limit, so 2x4s or 24 in spacing are out. Do not stretch the shed deeper either, and if you need more snow capacity, check your local permit office before you buy.
• Measuring side studs off the wrong end. The cut lists above run from opposite corners, so a stud read from the wrong end can come out nearly 3 ft off. Lay out both sloped plates first, then cut and number the studs wall by wall.
• Single felt at 3/12. Below 4/12 this list lays the felt in a double layer. Read the minimum slope on the shingle wrapper, and check your local permit office for the underlayment rule in your area.
• One birdsmouth instead of two. Each rafter bears on both walls, so it needs a seat at the front and at the back. Mark both from the pattern rafter.
• Raising the front wall short-handed. The bare front wall frame weighs about 207 lb, the heaviest lift on this shed. Frame it flat on the deck and raise it with a helper before any siding goes on.
• Untreated wood near the ground. Skids, rims and joists are pressure treated; plain framing lumber there rots. The USDA Wood Handbook explains why wet, untreated wood decays. Use hot-dip galvanized nails and treated-lumber rated screws in treated wood.

Setbacks, tie-downs and whether a 144 sq ft shed needs a permit vary by town, so check your local permit office before you order. For how to read any list like this one, see our shed material list guide, and for the base under the skids, shed foundation options. For other sizes, try the shed material calculator.

Get the full plan

We do not sell a 12×12 lean-to plan yet. If you want a printed set with every step for this footprint, the 12×12 gable shed plan is a 3DSHEDPLANS PDF with 3D drawings, cut details and its own printable material list. Download the free 12×12 gable preview PDF to see the format first.

For a single-slope roof, the 12×14 lean-to shed plan is the nearest size up, and the 12×18 lean-to shed plan adds more length. For a square single-slope shed, the 14×14 lean-to shed plan is 2 ft bigger each way, and a slightly smaller gable is the 12×10 gable shed plan. Compare every size on the lean-to shed plans and shed plans pages.

Frequently asked questions

How much lumber do I need for a 12×12 lean-to shed?

For a 12×12 lean-to on skids with an 80 in back wall and a 3/12 roof, the list calls for 52 2×4 framing boards, 16 plain 2×6 boards (12 of them 14 ft rafter stock), 12 pressure-treated 2x6s, 4 pressure-treated 4×4 skids and one 2×8 for the door header, plus 8 2×4 x 12 ft braces you reuse later.

What size rafters does a 12×12 lean-to shed need?

The list uses 2×6 rafters at 16 in on center, cut from 14 ft boards to 13' 10 1/4". They span 137 in against a 143 in limit at 30 psf ground snow, so there is little room to spare. If you get more snow than that, check your local permit office.

How many sheets of plywood, OSB and T1-11 for a 12×12 lean-to shed?

5 sheets of 3/4 in tongue and groove plywood for the floor, 7 sheets of 7/16 in OSB for the roof, 14 sheets of 5/8 in T1-11 (five 4×10, two 4×9, seven 4×8) and 1 sheet of 1/2 in plywood for the soffit and header fillers.

How many bundles of shingles does a 12×12 lean-to roof take?

7 bundles of 3-tab shingles, including the starter course, for a 3/12 roof of about 174 sq ft with 8 in eaves and 4 in rakes. At 3/12 the felt goes on in a double layer, and one 400 sq ft roll covers it.

Is there a 12 x 12 shed material list PDF?

The 3DSHEDPLANS 12×12 gable plan PDF has its own printable material list. We do not sell a 12×12 lean-to plan yet, so for the single-slope version this page is the list, and our lean-to plans in other sizes each include one.