The best time to start a shed is the week you check the rules, not the week the lumber arrives. A shed is small, but it is still a building, with a foundation, a floor, walls and a roof. Do the steps in this order and each one is ready for the next.
At a glance
| Skill | Intermediate. The lean-to and floating-foundation builds are good first building projects |
| Permit | Often required, depending on size and place. Ask your building office before you buy lumber |
| Pro work | Power to the shed, and any new circuit in your main panel |
| Time and cost | See the cost table. The videos give no overall time |
Safety first
- Permit and code. The floating-foundation video tells you to consult your local building office before starting, since code varies by location. The builder in that video cut joists to 96 in. so the outside dimension stays under what his local code allows. Your limit will differ, so ask. See Do You Need a Permit?.
- Electrical. The underground-power video says adding new circuits to the main breaker panel should only be done by a licensed electrician with the electrical service completely disconnected. Digsafe was called before digging in that video, so have underground lines located first. See When to Call a Licensed Electrician, Plumber or Gas Fitter.
- Roof work. Metal edges cut. Wear gloves and eye protection, and don’t work on a wet or sleeting roof.
- Cutting. Safety glasses and hearing protection for saws, and a respirator rated for spraying paint when you spray (the painting video says so).
- Nails. Keep your hands clear of brad and framing nails.
Step 1: Choose the size and the site
Both builds in the videos keep to simple sizes: a 4 ft by 8 ft lean-to, and a 10 by 16 ft shed. The lean-to’s back wall is cut to 99 in. so that 8 ft plywood and lumber can be stored against it, and the finished width is 48 in. before sheathing, which suits sheet goods.
Take the grass and black dirt off the site. The foundation video says organics must be removed so the blocks sit close to flush with finished grass.
Step 2: The foundation
The floating-foundation builder sets plastic Camo blocks on about an inch to an inch and a half of limestone screenings, levelled and tamped. He says each block is rated for 1,800 lb, more than double what his roughly 2,200 lb shed needs, even with snow load. That is the manufacturer’s rating as he reports it; check the label of the block you buy. Blocks take a 4×4 post, or a 6×6 if the design requires it. A plate compactor or hand tamper flattens the base.
A floating foundation is not right everywhere. Ask your building office whether it is allowed for your size and your frost conditions.
Step 3: Build the floor frame
The floor is built like a deck:
- Lay out a 2×8 pressure-treated frame, squared with one screw per corner.
- Flush the boards at one end and measure from there, because pressure-treated lumber varies in size. Seal the cut ends with preservative.
- Set joists 16 in. on centre, crown up. Mark both rim joists from the same end.
- Nail one nail per 2 in. of lumber width, he says, so four nails (or three nails plus a structural screw) on a 2×8. Add joist hangers.
- Level it. With no laser, he sets temporary screws at the corners and holds the frame slightly high because it sinks once loaded.
- Cover with 1/2 in. pressure-treated plywood, 4×8 sheets, joints staggered.
See also the deck basics in Deck Building Basics.
Step 4: Frame the walls
The 4×8 lean-to video shows the method:
- 2×4 studs 16 in. on centre on the long walls, 12 in. on the narrow side walls
- Three 3 in. nails at each end from a framing nailer, or 3 in. construction screws
- An 82 in. jack stud pair sets the door opening height
- Sheathe the back wall with 3/8 in. plywood before it goes up against another building
- Plumb it, check with a level, and clamp before nailing
Step 5: Roof framing
The lean-to builder lays out rafters with a speed square: the end cut is 8 degrees, the existing roof pitch is about 7 degrees, and the bird’s mouth is cut with a circular saw and finished with a jigsaw. The overhang is 9 in. Rafters are toenailed. He also mentions Simpson Strong-Tie brackets as an option, and the second video screws the rafters from underneath the wall plates to keep wind from lifting the roof.
Step 6: Sheathing and metal roof
- Walls: 3/8 in. plywood, 1.5 in. coated outdoor screws every 18 or 24 in.
- Roof deck: 3/4 in. plywood.
- Corrugated steel: In the asphalt-to-metal video, a 29 gauge corrugated galvanized panel goes over a membrane and 1×4 purlins, with foam closure strips at the ends.
- Overlap at least one full corrugation (lean-to video), or two corrugations (the other video). Follow the panel maker’s instructions.
- Screws go on the ridge of the corrugation, not in the valley, because water sheds through the valleys and a failed rubber washer there would leak. Tighten enough to squeeze the washer, not crack it.
- Cut with an angle grinder and a metal abrasive disc. A diamond blade struggled in one video.
Step 7: Trim, doors and finish
The lean-to uses 1×4 trim, with the bottoms floating about an eighth of an inch off the ground, and doors with three hinges each, with a 1/4 to 1/2 in. gap between the doors. The wood was wet and warped as it dried, and the centre hinges help keep things aligned.
For the inside, one video skips drywall and uses 5/8 in. OSB at about $21.50 a sheet (see Shed Interior Walls With OSB), with a quarter inch left at the bottom so moisture can dry out. For a workshop, see Painting a Plywood Shed Workshop.
Step 8: Power
Leave this to a licensed electrician. The video with master electrician Heath Eastman shows the steps: the trench goes about two feet down so the pipe is 18 in. deep, sand surrounds the conduit, ground rods are driven six feet apart, and metallic caution tape goes in before the final grade. The shed gets at least one receptacle and one light. Rules differ by place, so the video is a picture of the job, not a spec for yours.
Tools and materials
- Circular saw, framing nailer, level, speed square, angle grinder, jigsaw, power plane
- Pressure-treated 2×8, 2x4s, plywood, foundation blocks, corrugated metal, roofing screws with rubber washers, trim
Costs the videos state
| Item | Cost | Source |
|---|---|---|
| Whole 10×16 shed, builder’s estimate | about 3,500 (currency not stated; Ottawa) | Floating foundation |
| Material order, first delivery | 1,800 | Floating foundation |
| 5/8 in. OSB, per 4×8 sheet | about $21.50 USD | OSB video |
These are one builder’s numbers. Get local quotes.
Mistakes to avoid
- Building before asking the permit office.
- Starting without removing organic material under the blocks.
- Screwing metal roofing in the valleys.
- Running power yourself.
Put it on the calendar
- Before each winter, check the roof screws, the trim bottoms and the blocks for movement. We have no sourced interval; go by what you see.
- Keep wood trim an eighth of an inch off the ground, as the lean-to does.
See it in the projects
- DIY Lean-To Shed and Shed to Workshop Conversion
- Build a shed, Frame a wall, Install a corrugated metal roof, Run power to a shed, Insulate a shed ceiling
- The Workshop and Exterior and yard rooms, and the Roofing and Framing systems
Sources
- Shown on this site, source of the foundation, joist and cost figures. Floating Shed Foundation With Camo Blocks and a 2×8 Deck Frame (video) Source
- Shown on this site, source of the wall and rafter dimensions. Framing a 4×8 Lean-To Shed Against an Existing Shed: Walls to Doors (video, Modern Builds) Source
- Shown on this site, source of the sheathing, roof and trim details. Lean-To Shed: Plywood Walls, Metal Roof and Trim Finish (video, Modern Builds) Source
- Shown on this site, source of the metal roofing method. Replacing a Shed’s Asphalt Roll Roof With Corrugated Metal (video, Modern Builds) Source
- Shown on this site, source of the power guidance. Running Underground Power to a Shed: Trench, Conduit and Panel (video, Arnold Electric) Source
- Shown on this site, source of the interior wall option and sheet price. Shed Interior Walls With OSB: Cutting Around Boxes and Doors (video, Everyday Home Repairs) Source