How much lumber do I need for a 10x12 shed?

About 41 wall studs at 16 in on centre with corners, 132 linear ft of plates, and 20 rafters for a 6 in 12 gable. That comes to roughly 600 linear ft of 2x4, or about 400 board feet billed on the nominal size.

Do I need a permit for a shed?

It depends on floor area and your municipality, commonly with a threshold between 100 and 200 sq ft. There is no national figure. The exemption, where it exists, is from the permit only: zoning setbacks, lot coverage and height limits still apply, and electrical or plumbing always need their own permit.

What is the rafter run on a shed roof?

The full width of the building, because one rafter spans the whole way across. On a gable it is half the width. That difference quadruples the bending demand, which is why a lean-to needs a deeper rafter than a gable of the same width.

What pitch should a shed roof be?

Enough for the covering you are using. Most asphalt shingles are not approved below 2:12 and want special underlayment below 4:12. A low slope shed roof usually wants a membrane or standing seam instead, and that decision comes before the framing is cut.

Should a shed sit on skids or piers?

Skids are fine for most sheds and will move with frost heave and seasonal soil movement. Piers below the frost line stop that. A gravel pad under skids is the middle course: it drains, which prevents the rot that kills most skid-built sheds.

How many sheets of plywood for a 10x12 shed?

About 9 sheets for the walls at 10% waste and 8 for a 6 in 12 gable roof at 15%. Roof waste is higher because sheets are cut at the ridge and eaves and the offcuts rarely fit elsewhere.

Can I frame a shed at 24 inch centres?

For a nonbearing or lightly loaded shed wall, generally yes. Table R602.3(5) allows 2x4 studs at 24 in on centre for a wall carrying roof and ceiling only, up to 10 ft. It saves lumber and makes sheathing edges land on studs less often, so plan the layout first.

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Shed Framing Calculator

Framing arithmetic, and the size threshold that is not framing at all

A shed is the one building where the framing is genuinely simple and the paperwork is not. The studs and rafters are an afternoon's arithmetic. Whether you need a permit depends on a floor area threshold your municipality sets, and the exemption, where it exists, is from the permit and not from the setbacks.

Shed takeoff

Width

Length

Wall height

Roof style

Pitch (rise in 12)

Stud spacing

Rafter spacing

Overhang

Framed floor

Rafter run is the horizontal projection, which on a shed roof is the full width rather than half of it.

Specification summary

Generated from on . Reopen that address to reproduce these figures exactly.

Entered

Result

The table wants the horizontal projection, not the rafter

Worked example

A 10 ft by 12 ft gable shed, 8 ft walls, 6 in 12 pitch, 12 in overhang, framed floor.

Area. 120 sq ft, which is over the 100 sq ft threshold some municipalities use and under the 200 others use. Ask.
Walls. 44 ft of perimeter at 16 in gives 41 studs with corners.
Rafter run. A gable splits the width, so 5 ft, not 10.
Rafters. 20 rafters at 6 in 12, each 6.71 ft including the overhang.
Switch to a shed roof and the run becomes the full 10 ft: the rafter nearly doubles and needs a deeper section.

The roof style step is the one that catches people. A lean-to looks simpler than a gable and the rafter spans twice as far, which is why cheap shed plans so often have a bouncy roof.

The formula

The only term that needs care is the run, which depends on the roof style:

run = W/2 for a gable, W for a shed roof rafter = run × √(1 + (p/12)²) studs = ⌊ 12P / s ⌋ + 8

W, L: width and length, ft
P: perimeter, 2(W + L)
p: pitch, rise in 12
s: stud spacing, in on centre
+8: four corners at two extra studs each, which is a plain three-stud corner

Doubling the run more than doubles the rafter length, because the slope factor applies to a longer base. It also quadruples the bending demand, which is the real reason a lean-to needs a deeper rafter than a gable of the same width.

The threshold is not a framing question

Nearly every municipality exempts small accessory structures from a building permit, and the threshold is commonly somewhere between 100 and 200 sq ft. It is set locally and there is no national figure, which is why this page will not print one.

Three things about that exemption catch people out. It is an exemption from the permit, not from the code: the shed still has to be built to it. It is not an exemption from zoning, so setbacks, lot coverage and height limits all still apply. And it never covers electrical or plumbing, which need their own permit at any size.

The practical consequence is that a 120 sq ft shed placed 2 ft from a boundary can be perfectly exempt from a building permit and still have to be moved.

The framing itself is genuinely simple and the arithmetic here is exact. The part worth getting right before cutting is the roof style, because a lean-to spans the full width while a gable spans half of it.

A lean-to roof spans twice as far

On a gable, each rafter runs from the wall to the ridge, so the horizontal run is half the building width. On a shed or lean-to roof, one rafter runs the whole way across.

A 10 ft wide shed gives a 5 ft run with a gable and a 10 ft run with a lean-to. Doubling the run quadruples the bending demand, which is why so many cheap lean-to shed plans end up with a roof that visibly sags after a few winters.

Take the run to the rafter calculator and then to Tables R802.4.1(1) through (8) for the size. This page does the geometry and the counts, not the sizing.

Skids, piers and why sheds move

A shed on skids is not on a foundation, and that is usually fine and occasionally not. It will move with frost heave, and on clay it will move seasonally regardless. Doors that stick every spring are almost always a foundation symptom rather than a door problem.

Piers below the frost line stop that, and frost depth is a local number this site will not guess at. The footing calculator is the relevant page if you are going that way.

A gravel pad under skids is the middle course: it drains, which stops the rot that kills skid-built sheds, and it lets the whole thing move as one piece rather than twisting.

Frequently asked questions

How much lumber do I need for a 10x12 shed?: About 41 wall studs at 16 in on centre with corners, 132 linear ft of plates, and 20 rafters for a 6 in 12 gable. That comes to roughly 600 linear ft of 2x4, or about 400 board feet billed on the nominal size.
Do I need a permit for a shed?: It depends on floor area and your municipality, commonly with a threshold between 100 and 200 sq ft. There is no national figure. The exemption, where it exists, is from the permit only: zoning setbacks, lot coverage and height limits still apply, and electrical or plumbing always need their own permit.
What is the rafter run on a shed roof?: The full width of the building, because one rafter spans the whole way across. On a gable it is half the width. That difference quadruples the bending demand, which is why a lean-to needs a deeper rafter than a gable of the same width.
What pitch should a shed roof be?: Enough for the covering you are using. Most asphalt shingles are not approved below 2:12 and want special underlayment below 4:12. A low slope shed roof usually wants a membrane or standing seam instead, and that decision comes before the framing is cut.
Should a shed sit on skids or piers?: Skids are fine for most sheds and will move with frost heave and seasonal soil movement. Piers below the frost line stop that. A gravel pad under skids is the middle course: it drains, which prevents the rot that kills most skid-built sheds.
How many sheets of plywood for a 10x12 shed?: About 9 sheets for the walls at 10% waste and 8 for a 6 in 12 gable roof at 15%. Roof waste is higher because sheets are cut at the ridge and eaves and the offcuts rarely fit elsewhere.
Can I frame a shed at 24 inch centres?: For a nonbearing or lightly loaded shed wall, generally yes. Table R602.3(5) allows 2x4 studs at 24 in on centre for a wall carrying roof and ceiling only, up to 10 ft. It saves lumber and makes sheathing edges land on studs less often, so plan the layout first.

Check these numbers yourself

IRC Table R602.3(5), size, height and spacing of wood studsUpCodes, 2021 IRC as adopted in Connecticut. The stud spacing limits that apply to shed walls as much as house walls.
IRC R105.2, work exempt from permitUpCodes. The base code exemption for one-storey accessory structures, which jurisdictions amend freely. Confirm your own threshold locally.
AWC Wood Frame Construction ManualAmerican Wood Council. Prescriptive framing beyond the IRC tables.

How every figure here is verified: Sources & Method. Who builds this: About. Found something wrong? Tell us and it gets fixed or removed.

Figures on this page last checked against the source documents on 2026-09-08. Codes are amended locally; confirm against the edition your jurisdiction enforces.

Related calculators

The permit threshold is local. There is no national shed size exemption, and where one exists it exempts the permit and not the code, the zoning setbacks or the electrical. This page counts framing and does not size rafters: take the run to the rafter tables.