Building a Shed: DIY Guide
A prefab kit shed on a gravel pad is often a weekend build. Stick-built sheds and concrete foundations raise the difficulty meaningfully.
Conditional — Part DIY, Part Pro
A prefab kit on a gravel pad is DIY-friendly — panels are pre-cut and designed for assembly by one or two people in a weekend. Stick-built framing from raw lumber, or a concrete slab foundation, both raise the skill and effort bar meaningfully — still DIY-possible for an experienced builder, but budget significantly more time.
Skill Level
Intermediate
Time Required
1–2 days for a kit on a gravel pad; 1–2+ weeks for stick-built
Physical Demands
Heavy — lifting panels/lumber, leveling ground, moving gravel
What this costs
| Tool rental | Hand tamper or plate compactor $40–$70/day |
| Your time | 1–2 days for a kit on a gravel pad; 1–2+ weeks for stick-built |
What moves the number
- The permit threshold you land on — A 10x12 shed is paperwork-free where the exemption runs to 200 square feet and adds fees, drawings and inspections where it has been amended to 120.
- Foundation type — A gravel pad is materials and a rental compactor. Piers add concrete and excavation to your local frost depth; a slab adds formwork, reinforcement and usually a contractor.
- Site slope and drainage — A level site needs a few inches of gravel. A sloped site needs retained fill or stepped piers, and that grading regularly costs more than the kit.
- Roof pitch — A slope between 2:12 and 4:12 requires doubled underlayment, and an ice-dam region requires an eaves membrane. Both are cheap against a roof that comes off in year five.
Run your own numbers with the cost calculator.
Before you start
A shed looks like the friendliest structural project in the yard, and for a kit on flat ground it genuinely is. What makes it worth planning is that a shed is a small building with all of a building's failure modes compressed into a weekend: a foundation that can settle, a floor that can rot, walls that must stay square, and a roof that has to shed water for twenty years without anyone going up to look at it.
Settle the permit question first, and accept that nobody online can answer it for you. The 2021 IRC's exempt-work list, reproduced by Grant County, Washington, exempts one-story detached accessory structures other than storm shelters provided the floor area does not exceed 200 square feet — but the City of American Canyon, California adopted its own version of that section in 2022 setting the limit at 120 square feet. One model code, an 80-square-foot gap, and an 8x12 shed landing on opposite sides of the line. Read the sentence people skip, too: exemption from permit requirements does not grant authorisation for any work done in violation of the code or any other laws or ordinances of the jurisdiction. Zoning setbacks are a separate approval that applies regardless of size. Then settle the foundation, because it is the only part you cannot revisit: anything in the ground follows the American Wood Council's footing rule for light exterior structures — bearing on undisturbed soil at least 12 inches below the undisturbed ground surface or below the frost line, whichever is deeper, with the frost line set by the authority having jurisdiction.
Code and permits
Most jurisdictions exempt small detached accessory structures from a building permit, but the threshold is local and the exemption is narrower than it sounds. The model figure is 200 square feet; real jurisdictions run below it, often conditioned on there being no utilities in the building. Separately from the building permit, zoning setbacks and lot-coverage limits apply to every shed regardless of size, and utilities almost always need their own permit.
International Residential Code 2021, as reproduced by Grant County, Washington § R105.2, Building item 1 — Other than storm shelters, a permit is not required for one-story detached accessory structures provided the floor area does not exceed 200 square feet. Exemption from permit requirements does not grant authorisation for work done in violation of this code or any other laws or ordinances of the jurisdiction.
International Residential Code roofing provisions, as applied by the City of Council Bluffs, Iowa § R905 — asphalt shingles — Asphalt shingles may only be used on roof slopes of 2:12 or greater, must be fastened to solidly sheathed decks with not fewer than four fasteners per strip shingle unless the manufacturer requires more, and require doubled underlayment overlapped 19 inches on slopes from 2:12 up to 4:12.
The two permit thresholds cited above are 80 square feet apart and both are correct where they apply. Your building department sets yours, decides which code edition is in force, and may attach conditions — commonly that the structure contains no mechanical, electrical or plumbing work. Zoning setbacks, lot coverage and any HOA covenant are separate approvals that apply even to a fully exempt shed.
Permit requirements for this project vary by state and municipality. Select your state above for specific guidance, or check with your local building department before starting work.
Stop and call a pro if…
These are hard stops, not cautions. If you hit one, the job is finished for you until a licensed trade or your building department signs off on it.
The shed is larger than your jurisdiction's exempt floor area, or you plan to run power, water or heat into it
Above the threshold, or with utilities, the building becomes permitted work with plan review and inspections. Building first and asking later turns a fee into an enforcement problem, and an unpermitted structure surfaces at sale.
Who to call
Your building department for the permit path, and planning or zoning separately for setbacks and lot coverage.
International Residential Code 2021, as reproduced by Grant County, Washington § R105.2, Building item 1 — The exemption for a one-story detached accessory structure applies only up to the adopted floor area — 200 square feet in the model text, less where amended — and exemption from a permit never authorises work that violates the code or other local ordinances.
The roof design you want is flatter than 2:12
Below that slope asphalt shingles are not a permitted roof covering at all. Installing them anyway produces a roof that looks finished and leaks at every lap, and no amount of sealant fixes a covering used outside its slope range.
Who to call
A roofing contractor, to specify a low-slope membrane system — or change the design so the pitch clears 2:12.
International Residential Code roofing provisions, as applied by the City of Council Bluffs, Iowa § R905 — slope — Asphalt shingles shall only be used on roof slopes of 2:12 or greater. For slopes from 2:12 up to 4:12, underlayment shall be installed by overlapping successive sheets of felt by 19 inches to form a double underlayment.
You cannot set a ladder safely, or the roof is steep, wet or high enough that you would be working off the ladder rather than off the roof
A ladder set too steeply, or one whose rails stop at the fascia, fails at the moment you transfer your weight onto or off the roof — and a fall from shed height is routinely a serious injury.
Who to call
A roofing contractor, or at minimum a second person and proper equipment. Do not solve it by leaning further.
OSHA, 29 CFR 1926.1053 § 1926.1053(b)(1), (b)(4) and (b)(5)(i) — Where a ladder is used to access an upper landing surface, its side rails must extend at least 3 feet above that surface; a non-self-supporting ladder must be set so the horizontal distance from the top support to the foot is approximately one-quarter of the working length; and ladders must be used only for the purpose for which they were designed.
Safety Warnings
- • Call 811 before any digging, even for a shallow gravel pad excavation
- • Get a second person for lifting wall panels or roof trusses
- • Brace standing walls to ground stakes until all four are joined — an unbraced panel is a sail
- • Set ladders at roughly one-quarter of their working length out from the wall, with rails at least 3 feet above the roof edge
- • Wear gloves and eye protection when cutting treated lumber, and never burn treated offcuts
Choosing your materials
| Option | Best for | Trade-off |
|---|---|---|
| Prefab kit on a gravel pad | Most homeowners. Panels are pre-cut, hardware is in the box, and two people can usually stand the walls in a day. | You inherit the kit's design decisions, including roof pitch and fastener spec. Read its instructions before you build the pad — the pad is sized to the kit, not the other way round. |
| Treated skids or pier blocks on gravel | Small sheds on level ground, sloped sites, and anywhere you may want to move the building later. | Skids sit on or near soil, so under the AWPA use categories they must be Use Category 4A or higher — the same category specified for ground-contact posts. Piers are footings, and inherit your local frost depth. |
| Poured concrete slab | Workshops, heavy equipment, anything intended to be permanent. | The most expensive and least reversible option, and the pour is the step most worth hiring out. A permanent foundation is also what tips a shed into permit territory in many jurisdictions. |
Tools & Materials
Tools
- Drill/driverBuy
- Circular sawBuy
- Level (4 ft)Buy
- Wheelbarrow (for gravel/concrete)You likely own
- Hand tamper or plate compactorRent — $40–$70/day
Materials
- Shed kit or lumber/siding/roofing materials
- Gravel or concrete for foundation, plus landscape fabric
- Treated skids or pier blocks — UC4A or higher for anything in ground contact
- Hot-dipped galvanised or stainless fasteners for treated lumber
- Solid roof sheathing, underlayment to ASTM D226/D4869/D6757, and shingles rated for your slope
- Ice barrier membrane if your area has a history of ice damming
Step-by-Step
- 1
Check permit requirements and call 811
1–2 weeks of lead time
Many jurisdictions exempt small sheds from permitting, but thresholds vary — confirm before starting, and always call 811 before any digging for footings or a gravel base.
Ask two separate questions, because two separate offices answer them. The building question is the floor-area threshold below which a detached accessory structure needs no permit — 200 square feet in the model code, 120 in American Canyon, often conditioned on there being no mechanical, electrical or plumbing work. The zoning question is setbacks and lot coverage, and it is the one that gets sheds relocated after they are built, so get it in writing. Then call 811 and wait the full locate period.
Check your workYou know your own square-foot threshold, your setbacks and your frost depth, and there are locate marks on the ground before a shovel moves.
⚠ Being under the permit threshold is not the same as being unregulated — the same section states that exemption does not authorise work performed in violation of the code.
- 2
Choose and prepare the site
Half a day · Level (4 ft), Wheelbarrow (for gravel/concrete)
Pick level ground with good drainage, away from property lines (check local setback requirements).
Water kills sheds, and it arrives from below far more often than through the roof. Pick the high point of the yard, avoid the base of a slope where run-off collects, and set the footprint out with string lines, checking square by diagonals before you excavate. Leave working room on all four sides, and measure the setback from an actual property marker — a fence is not a survey.
Check your workDiagonals match, the site drains away from the footprint in every direction, and the setback is measured from a real property marker.
- 3
Build the foundation
1 day · Hand tamper or plate compactor, Level (4 ft), Wheelbarrow (for gravel/concrete)
For a gravel pad: excavate a few inches, add landscape fabric, then compact gravel level. For a concrete slab: this step usually means hiring a pro for the pour.
A gravel pad is not a pile of gravel. Strip the topsoil and any organic material — it decomposes and settles — lay fabric, then build the gravel in shallow lifts, compacting each before adding the next. Compacting one deep lift only densifies the top of it, which is why pads settle a season later. Extend the pad past the footprint on all sides. Piers follow the rule any exterior footing does: bearing on undisturbed soil at least 12 inches below the undisturbed ground surface or below the frost line, whichever is deeper.
Check your workA straightedge finds no dip greater than a shim's thickness anywhere on the pad, and the pad extends past the building footprint on every side.
- 4
Assemble the floor frame
2–4 hours · Circular saw, Drill/driver, Level (4 ft)
Set skids or a floor frame square and level on the foundation before building up.
Everything above this is only as square as the floor: measure both diagonals and adjust until they match before the sheathing goes down, because once the deck is on the frame keeps whatever shape it had. Match the treatment to the exposure — under the AWPA use categories anything in ground contact needs Use Category 4A or higher, a sill plate is UC2 and above-ground joists and beams are UC3B, all printed on the end tag. Use hot-dipped galvanised or stainless fasteners: modern treatments are corrosive to plain steel.
Check your workDiagonals match within about 1/8 inch, the frame does not rock on the pad, and every board touching the ground carries a UC4A or higher tag.
- 5
Build or assemble the walls
4–8 hours · Circular saw, Drill/driver, Level (4 ft)
Kit walls are pre-built panels that bolt together. Stick-built walls are framed from raw lumber on-site.
Build or unpack all four walls before standing any of them, and stand them in the order the instructions give — a kit's panels are cut for a specific sequence. Brace as you go: a standing wall tied to nothing is a sail. Check plumb on both faces of each corner before fastening permanently and again after the last wall goes up, because joining the fourth wall almost always moves the first.
Check your workEvery corner reads plumb in both directions, top plates are level all the way round, and door openings measure the same top and bottom. Hang doors last, to the opening you actually have; treated siding and trim want UC3A or higher, and every cut end wants a field-applied preservative.
⚠ Never stand a wall panel alone if the instructions call for two people. Kit panels are heavy, top-heavy and fall as a unit.
- 6
Install the roof
1 day · Circular saw, Drill/driver
Follow the kit's roof truss instructions, or frame and shingle a stick-built roof.
Slope decides the roofing before anything else. Asphalt shingles may only be used on roof slopes of 2:12 or greater, and from 2:12 up to 4:12 the underlayment must be doubled — successive sheets of felt overlapped by 19 inches — per the City of Council Bluffs' building guide to the IRC roofing provisions. The same guide requires roofing nails of galvanised steel, stainless steel, aluminium or copper, minimum 12-gauge shank with a minimum 3/8-inch head, penetrating the roofing material and 3/4 inch into the sheathing or all the way through thinner sheathing, with four fasteners per strip shingle unless the manufacturer requires more. Underlayment must conform to ASTM D226, D4869 or D6757. Where ice has historically formed at the eaves, an ice barrier must extend from the lowest edges of all roof surfaces to at least 24 inches inside the exterior wall line.
The other half of this step is the ladder. OSHA requires non-self-supporting ladders to be set so the horizontal distance from the top support to the foot is approximately one-quarter of the working length, side rails to extend at least 3 feet above the upper landing surface, and ladders to be used only as designed — which is exactly the improvisation a short shed roof invites.
Check your workEvery shingle has at least four nails, none overdriven or high, and the underlayment configuration matches your actual slope.
⚠ Nails that miss the sheathing, sit proud, or go through the shingle above show up as leaks in year three and void most warranties.
Common mistakes
Assuming the 200-square-foot exemption applies where you live
Why it happens
It is the figure in the model code and it is quoted everywhere online, so it reads like a national rule.
The fix
Check your own jurisdiction — the same section runs to 120 square feet in American Canyon, California. If a shed is already up and over the local limit, the route back is a retroactive permit application, not silence: an unpermitted structure surfaces at sale.
Treating a permit exemption as an exemption from the rules
Why it happens
'No permit required' sounds like 'no requirements', and nobody is coming to inspect.
The fix
Re-read the opening sentence of the section: exemption does not authorise work done in violation of the code or any other local law. Setbacks and lot coverage still apply, and they are handled by planning rather than the building department.
Compacting the gravel pad in one deep lift
Why it happens
It is faster, the surface comes out flat, and the pad looks identical to a properly built one on the day.
The fix
Build in shallow lifts and compact each. A pad that settles differentially racks the floor frame, and once the walls are on the fix is jacking and re-shimming rather than re-doing the pad.
After the job: care and maintenance
First spring, then annually
Walk the perimeter after the ground thaws and check that the pad has not settled and the doors still close squarely. Movement caught in year one is a shim; in year five it is a floor frame.
Twice a year
Clear leaf litter off the roof and out of the gap between the shed and any fence or hedge — debris held against siding keeps it wet.
Annually
From the ground, look along the roof plane for lifted or missing tabs after the first big wind of the season.
Every 2–3 years
Re-coat siding and trim and re-seal weathered cut ends. Preservative treatment protects against decay, not against UV.
FAQ
Do I need a permit to build a shed?
It depends on your jurisdiction, and the spread is real. The 2021 IRC's exempt-work list, as reproduced by Grant County, Washington, exempts one-story detached accessory structures other than storm shelters up to 200 square feet. The City of American Canyon, California adopted its own version of that section in 2022 setting the limit at 120 square feet. Some jurisdictions also condition the exemption on there being no mechanical, electrical or plumbing work. Confirm your own number before you pick a shed size.
What roof pitch does a shed need?
For asphalt shingles, at least 2:12 — below that they are not a permitted roof covering, whatever the shed plan shows. Between 2:12 and 4:12 the underlayment has to be doubled, with successive sheets of felt overlapped 19 inches; only above 4:12 does a single layer suffice. Those figures are from the City of Council Bluffs' building guide to the IRC roofing provisions. A flatter roof is not impossible, it just needs a low-slope membrane system rather than shingles.
How much of the shed should I do with a second person?
All of the wall raising and all of the roof. Kit wall panels are heavy, top-heavy and awkward, and an unbraced standing wall is a sail in a gust. Roof work adds the ladder, where OSHA's rules exist for exactly the improvisation a small roof invites: rails extending at least 3 feet above the surface you step onto, a non-self-supporting ladder set out about a quarter of its working length, and ladders used only for what they were designed for. A short roof is not a safe roof; it is a low one.
If my shed is under the size limit, are there no rules at all?
No — this is the most common misreading. The same code section says in its opening sentence that exemption from permit requirements does not grant authorisation for any work done in violation of the code or of any other laws or ordinances of the jurisdiction. Structural requirements still apply, and zoning setbacks and lot coverage are a separate approval handled by planning. A permit-exempt shed placed inside a setback still has to move.
What treated lumber do I need for a shed floor?
Match the AWPA use category to the exposure and read it off the end tag. Anything in contact with the ground — skids, posts, blocks bearing on soil — needs Use Category 4A or higher. A sill plate is UC2, above-ground joists and beams are UC3B, and siding, fascia and trim are UC3A or higher. Use hot-dipped galvanised or stainless fasteners with any of it: modern treatments are corrosive to plain steel.
Sources
Every figure, clearance and code section on this page traces to one of these. Manufacturer instructions govern their own product and override anything general said here.
- Grant County, Washington. 2021 International Residential Code (IRC) Section R105 Permits — work exempt from permit — accessed September 3, 2026.The 200-square-foot model exemption and the short list of exempt electrical work.
- City of American Canyon, California. Municipal Code 16.03.040 — Section R105.2.1, work exempt from permits (Ordinance 2022-05) — accessed September 3, 2026.The same section amended to 120 square feet — proof the threshold is local.
- City of Council Bluffs, Iowa — Building Department. Building Guide: Roofing & Re-Roofing (International Residential Code, R905 and R908) — accessed September 3, 2026.2:12 minimum slope, doubled underlayment to 4:12, nail spec, four fasteners per strip shingle, ice barrier.
- U.S. Occupational Safety and Health Administration. 29 CFR 1926.1053 — Ladders — accessed September 3, 2026.Side rails 3 feet above the landing, the quarter-of-working-length setback, and using ladders only as designed.
- American Wood Protection Association. Select the Right Preserved Wood for Your Project — AWPA Preserved Wood Use Categories (2021) — accessed September 3, 2026.UC4A for ground contact, UC2 for sill plates, UC3B above ground, UC3A for siding and trim — all read off the end tag.
- American Wood Council. Prescriptive Residential Wood Deck Construction Guide (DCA 6), based on the 2015 International Residential Code — accessed September 3, 2026.Footings 12 inches below undisturbed ground or below the frost line, whichever is deeper.
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