How to Build a Shed: Step-by-Step Guide

Knowing how to build a shed comes down to eight stages, always in the same order: plan and permits, foundation, floor, walls, rafters, roof, siding and doors, and anchoring. Every stage rests on the one before it. A flat foundation gives you a square floor, a square floor gives you plumb walls, and plumb walls give you rafters that fit.

This guide walks through all eight with the numbers for a default 8x10 gable shed from the shed designer. That shed has 2x4 walls, 2x6 rafters at 6/12, a skid foundation and asphalt shingles. If your shed is a different size, the stages stay the same and the numbers change, and the designer works them out for you.

How to build a shed: plan first

Decide the size, check the rules and pick the spot before you buy anything. A shed built without that check is the one that gets moved or torn down.

Pick the size

The designer covers sheds from 4 to 16 ft wide and 4 to 24 ft deep, with gable roofs from 4/12 to 6/12 and lean-to roofs from 2/12 to 4/12. The first number in a size is the width and the second is the depth, so a 10x12 shed is 10 ft wide and 12 ft deep. The free plans cover 20 sizes. The common ones are the 6x8 for hand tools, the 8x10 for a mower and a workbench, and the 10x12 for a storage shed with a work area.

Pick the size before the permit call, because the floor area is the first number a building department asks about. Floor area is width times depth: an 8x10 is 80 sq ft, a 10x12 is 120, and a 12x16 is 192.

Gable or lean-to

A gable roof slopes both ways from a ridge, and a lean-to roof has one slope. The lean-to is the simpler build because every rafter is the same cut and there is no ridge board. The 10x8 lean-to plan, 10 ft wide and 8 ft deep with a 3/12 roof, has 80 sq ft, 9 rafters, 4 skids and 7 floor joists, and stands 9 ft 8-1/2 inches tall. Every plan name gives the width across the door wall first and the depth second. This guide follows the gable, and the stages are the same for both. The lean-to shed guide covers the single-slope build.

Check the permit rules

Permit rules vary by jurisdiction, so make one call to your building department before you commit to a size. Here is what a few real rules look like.

• Model code: the 2021 International Residential Code, section R105.2, exempts one-story detached accessory structures up to 200 sq ft from a building permit (Grant County, WA, reprinting IRC 2021 R105). That threshold covers every plan we offer up to 10x20, which is exactly 200 sq ft. The 12x20, 12x24 and 16x20 plans are above it.
• Local numbers differ: Elgin, Illinois defines a shed as an accessory structure of no more than 150 sq ft, and it requires 4 ft from any other building (City of Elgin, Shed Quick Guide).
• Exemption is not permission: the same model-code section says an exemption does not authorize work that violates the code or other laws or ordinances, and zoning rules such as setbacks apply whatever the size.

Our shed permit basics guide covers what to ask and what to bring. Ask about permits, setbacks, height limits, and which foundations they accept.

Call 811 and choose the spot

Call 811 a few business days before you dig. It is the free national before-you-dig service that gets buried utilities marked (Common Ground Alliance, call811.com). Then walk the site after a hard rain. Water that pools there will pool under your shed, so pick higher, well-drained ground and leave room around the walls to work.

Pick a foundation

The designer offers two: 4x6 skids on a gravel pad, or 4x4 beams on concrete deck blocks. Slabs and piers are outside what it models, so you plan them yourself.

Skids on a gravel pad

This is the default. A compacted gravel pad, 12 inches larger than the shed on every side and 4 inches thick, carries pressure-treated 4x6 skids set on edge and running front to back. An 8x10 has 3 skids of 10 ft, and the pad takes 1.48 cubic yards of stone before you allow for compaction.

The number of skids comes from the width, and the pad volume from the footprint. The gravel shed base guide has the volume for every common size, the right kind of stone and the pad build, and the shed on skids guide has the skid count, spacing and the floor build.

Deck blocks and beams

On a slope, the alternative is 4x4 pressure-treated beams on concrete deck blocks. The designer puts the beams at the same spacing as skids, with blocks under each beam as close as the 4x4 needs to pass its span check and never more than 4 ft apart, which is 12 blocks for the 8x10. The foundation is 11-1/2 inches tall in that case, against 5-1/2 inches for skids. The shed foundation guide covers both, with leveling and squaring, and the concrete block shed foundation guide has the block count for every size.

The lumber rating

Anything that touches the ground or the stone must be rated for it. The wood preservers’ use category for ground contact is UC4A (Preserved Wood, AWPA Use Categories). The designer marks skids, beams, floor joists and rim joists as pressure-treated for ground contact. Buy that grade, not the cheaper above-ground grade.

Build the floor frame and subfloor

The floor is a rectangle of 2x6 pressure-treated lumber with a plywood deck on top. Get it square and level and everything after it is easier.

The frame

The 8x10 floor has two 10 ft rim joists and 9 floor joists 93 inches long, all 2x6 pressure-treated. The joists run across the skids at 16 inches on center. Nail each joist through the rim joist at both ends with three 16d common nails.

Square and level

Measure both diagonals. When they are equal, the frame is square. Rack it until they match, then fasten it to the skids so it cannot shift. Check level across the joists in several places and fix a low skid now, not after the walls are up.

The subfloor

Use 3/4 inch tongue-and-groove plywood in 4x8 sheets, with the long edges across the joists and the end joints staggered. An 8x10 takes 3 sheets, about 150 2-inch exterior screws and 2 tubes of subfloor adhesive. With skids, the top of the subfloor sits 11-3/4 inches above the pad. The shed floor guide goes through joist spacing, the span check and the plywood.

Frame and raise the walls

Walls are 2x4 studs at 16 inches on center between a bottom plate and a double top plate. The frame shed walls guide covers the layout in depth. This section gives the plan.

The parts of a wall

The designer cuts its gable-shed studs 84-1/4 inches long from 8 ft 2x4s. With one bottom plate and two top plates, each 1-1/2 inches thick, that makes a finished wall 88-3/4 inches tall. That height lets one 4x8 siding panel run from 1 inch below the floor frame, the designer’s own allowance, to the top of the wall with no horizontal seam. Top plates overlap at the corners to tie the walls together.

Openings and headers

Every door or window gets a king stud, a jack stud and a double header. The header length is the opening plus 3 inches. The designer’s minimum header is two 2x6s. On a load-bearing wall it picks the smallest 2x6, 2x8, 2x10 or 2x12 pair that passes its deflection check. On a gable shed, the side walls that run the full depth carry the roof, so those are the load-bearing ones.

The default 8x10 has one door opening 48 inches wide and 78 inches tall in the front wall, with a 2x6 header 51 inches long in two plies, two jack studs 76-1/2 inches long and 3 cripples above the header. It has one 24 by 24 inch window in the right wall. The door itself is not part of the plan: the designer frames the opening and sizes the header, and you build or buy the door separately.

Raise and brace

Build each wall flat on the subfloor, stand it up, plumb it, and brace it with a temporary diagonal until the top plates tie the corners together. Check plumb on two faces of every corner. Then nail the cap plate on so it laps the joints below.

Rafters and ridge

The rafters carry the roof, and they are where a shed goes together fastest, because every common rafter is the same cut. The shed rafters guide covers the layout and cuts.

Size and spacing

The designer tries 2x6, then 2x8, 2x10 and 2x12, and keeps the first size that passes its span check. It never uses a 2x4. Every one of our plans ends up at 2x6, with a 2x8 ridge board on the gable sheds. The 8x10 has 18 rafters, each about 62-5/16 inches long, and a ridge board 10 ft long. The default snow load is 30 psf.

For a sense of margin, an 8x10 rafter spans 47-1/4 inches horizontally, and a 2x6 SPF No. 2 rafter at 16 inches on center can span 11 ft 11-1/8 inches in the designer’s calculation. Model-code span tables give similar numbers: a rafter table the Central Kansas Council of Governments calculated from the 2003 International Residential Code tables lists 11 ft 11 inches for the same case. Your local table is what counts, and that edition is old, so read the current one from your building department.

Cutting and raising

Cut a pattern rafter first: a plumb cut at the ridge, a birdsmouth where it sits on the top plate, and a tail for the eave. The designer’s birdsmouth seat is 3-1/2 inches long, and it warns when a notch cuts deeper than a third of the rafter. Test the pattern on the wall, trace it onto the rest, and cut them all.

Set the ridge board on temporary posts, nail the rafters to it in pairs, and tie every pair to the wall plates. The designer’s list includes 9 rafter ties, 2x4 by 96 inches, and 18 rafter-to-plate connectors, one at every rafter bearing.

Pitch

Pitch is the inches of rise for every 12 inches of run. The designer offers 4/12, 5/12 and 6/12 for gable roofs and 2/12, 3/12 and 4/12 for lean-tos, and it has no steeper pitch. The default 6/12 puts the 8x10’s ridge 117-5/8 inches above the sole plate and its total height at 10 ft 9-3/8 inches above the ground. The shed roof pitch guide has the chart and a calculator, and the trusses vs rafters guide explains the other way to frame a roof.

Sheathe and roof

Sheathe the rafters, cover them with underlayment and drip edge, then shingle. The how to build a shed roof guide takes this stage step by step.

Roof sheathing

The designer uses 7/16 inch OSB in 4x8 sheets, 6 sheets for the 8x10. A panel rated 24/16 with a 7/16 inch nominal thickness has a maximum roof span of 24 inches, so it works on rafters at 16 or 24 inches on center. Panel edges that fall between rafters need clips or blocking (City of Republic, MO, Roof and Subfloor Sheathing Spans, IRC Table R503.2.1.1(1)). The designer’s list nails the OSB with 8d nails, 6 inches apart on the edges and 12 inches in the field. Your local code sets the nailing schedule, so check it.

Underlayment, drip edge, shingles

The 8x10 roof takes 5 pieces of 10 ft drip edge, a roll of synthetic underlayment, 20 ft of starter strip, 10 ft of ridge cap and 4 bundles of asphalt shingles. That is 1.01 squares of roof plus 10% for waste, at 3 bundles per square.

Asphalt shingles are only for roofs of 2/12 pitch or greater, and a roof from 2/12 to 4/12 needs double underlayment, according to the summary of IRC section R905.2 that the City of Hopkins, Minnesota publishes. The designer offers nothing flatter than 2/12 and warns below 4/12. The shingle guide has the courses and the bundle count for every size. Metal roofing has its own minimum pitch, 3:12 for lapped panels without lap sealant in the 2021 IRC, R905.10.2, so check the manufacturer’s instructions and your local code, and see the metal roof guide.

Siding, trim, doors and windows

The siding is the shed’s skin, and the door and window openings were framed earlier.

Panel siding

T1-11 is a registered trade name for an APA 303 Rated Siding panel: an all-veneer plywood panel with shiplapped edges and grooves 1/4 inch deep and 3/8 inch wide, spaced 4 or 8 inches on center. APA says to install it over a water-resistant barrier such as building paper or house wrap (APA, APA Rated Siding). The designer counts 4x8 panels, which cover the floor frame and the default wall in one piece, and 4x8 panels for the gable triangles. The 8x10 uses 10 wall panels and 1 gable panel, plus 2 pieces of 10 ft Z-flashing for the 16 ft of horizontal joint where the gable panels meet the wall panels at the top plate. LP’s panel siding instructions ask for Z-flashing and a 3/8 inch gap at horizontal seams. If you raise the wall past what one 4x8 covers, the designer lets you pick 4x8 panels stacked with a joint on Z-flashing over 2x4 blocking, or 4x9 panels, which it flags as usually special order. The designer’s list fastens them with galvanized 8d siding nails, 6 inches apart on edges and 12 inches in the field. The shed siding guide compares the other types and gives the panel count for every size.

Trim

The 8x10’s trim list is 8 corner boards 1x4 by 96 inches, two at each corner, 2 fascia boards 1x6 by 120 inches, and 4 rake boards 1x4 by 60-3/8 inches. Every piece is cut whole, with no joint, and short pieces share a board when they fit: the corners take eight 1x4s at 8 ft, three rake boards fit on one 16 ft 1x4 and the fourth on another 8 ft board, and the fascia takes two 1x6s at 12 ft. A trim run longer than 16 ft is two boards with a butt joint over a rafter tail, a 3/16 inch gap, sealed, since LP’s trim instructions say not to use scarf joints.

Doors and windows

We do not give plans for the door itself, so use the opening size from your plan to order or build one. The default opening is 48 inches by 78 inches. The designer’s lists offer door openings from 24 to 96 inches wide and 60 to 96 inches tall, and up to 4 windows, each 12 to 48 inches wide and 12 to 48 inches tall, and it flags any opening that does not fit its wall. Which way a door swings, and what hardware to use, is your call and your site’s. The how to build shed doors guide covers two door builds, and the shed door ideas guide compares the types.

Anchor the shed

A light building can move in a strong wind. The designer’s parts list for a skid shed includes 4 ground anchors, one near each corner, with a note to check local wind rules.

Local rules can go further. Elgin, Illinois accepts a gravel base only with code-approved tie-downs, and Prince William County, Virginia exempts a shed from a permanent foundation only if it is anchored to withstand the wind loads its state code sets. Ask your building department what it approves, and follow the anchor maker’s instructions for your soil. The shed anchoring guide has the steps for skids, slabs and deck blocks.

Materials and tools

The designer’s lumber list for the default 8x10 has 94 boards. Softwood lumber is sold by nominal size and measures smaller: a 2x4 is 1-1/2 by 3-1/2 inches, a 2x6 is 1-1/2 by 5-1/2, a 2x8 is 1-1/2 by 7-1/4, a 2x10 is 1-1/2 by 9-1/4, and a 4x4 is 3-1/2 by 3-1/2 (Southern Pine Inspection Bureau, citing PS 20).

The 8x10 material list

Those are the designer’s quantities, and they include 15% spare on the nails and 10% waste on the shingles. On sheds deeper than 16 ft, the designer splices the long plates, rim joists, skids, ridge and fascia over supports, so no board is longer than 16 ft unless you ask for 20 or 24 ft stock. The shed material list guide has the full lists for the 10x12 and 12x16 and the totals for every size.

What the big items cost

The designer does not price materials, so here is one dated example. At one Home Depot store in San Diego County, California (Otay Mesa, ZIP 92154), on September 29, 2026, a 4x6x10 pressure-treated timber was $37.78, a sheet of 3/4 inch tongue-and-groove plywood $49.94, a sheet of 7/16 inch OSB $15.35 and a bundle of architectural asphalt shingles $46.97. At those prices, the 3 skids, 3 subfloor sheets, 6 OSB sheets and 4 shingle bundles on this list come to $543.14 before tax, and that is only four lines of the list.

That is one store on one day, not a national price. Lumber prices move, and stores and regions differ, so take the full list to your lumber yard and a home center and ask each for a quote.

Tools

For a shed like this you need: a circular saw, a speed square, a framing square, a 4 ft level, a 25 ft tape, a chalk line, a hammer or a framing nailer, a drill, a utility knife for the roofing, a shovel and rake for the pad, a tamper or a rented plate compactor, and a ladder. A helper for the wall raising and the rafters is worth more than any tool.

Common mistakes when you build a shed

Most shed problems are set in the first stages and show up later, when they are hard to fix.

Skipping the square check

A floor frame that is out of square carries the error up through the walls and into the roof sheathing. Measure the diagonals on the floor frame, then on every wall and again before the rafters go on.

Bracing too late

A wall stands on its own only until the first gust. Brace every wall as you raise it, and leave the braces on until the cap plates tie the corners together and the sheathing is on.

Cutting every rafter from scratch

Cut one pattern rafter, test it on the wall, and trace it onto the rest. A pattern that is off by a quarter inch is a pattern you fix once.

Ordering lumber before the plan is final

Change the size after you buy and you are holding boards the plan no longer needs. Settle the size, permit and foundation first, then order from the list, and ask the yard about long boards early.

Forgetting drainage

A shed that sits in a low spot stays damp under the floor whatever it is built on. Grade the ground away from the foundation before you start, and keep gravel, mulch and soil from piling against the skids or rim joists later.

What the designer and the free plans do for you

The shed designer takes your width, depth, roof type, pitch, door, windows and snow load and returns the span checks, the lumber list and a free summary PDF; the $29 builder’s plan adds every cut length, the framing drawings and the rafter template. The 20 free plans have all of that for common sizes at no cost: the 8x10 gable shed is the one this guide follows, and the 10x12 gable shed is the next size up.

It has limits, and you should know them before you build. The designer frames with 2x4 walls and SPF No. 2 lumber, from 20 to 80 psf of snow, and its math is a planning aid, not engineering. It does not design lofts, ramps, doors, prefabricated trusses, gambrel roofs, insulation or wind loads, and it does not price materials. Check the plan against your local code and your building department before you build.