Building a wooden garden shed starts with three decisions: what you're storing, where the shed goes, and which materials will last in your climate. Get those right and the rest is straightforward carpentry. This guide takes you through each stage — foundation, walls, roof, doors and finishing — with the practical detail you actually need.
Before you pick up a tool, check out our overview of multifunctional wooden shed designs if you want inspiration on layouts that combine storage with a workshop or covered seating area.
A 3 × 3 m footprint comfortably holds a lawnmower, two bikes and a full set of garden tools. Larger plots may justify 3 × 4 m or more. Walk the spot at different times of day: avoid low-lying areas where water pools and leave at least 60 cm clearance on each side for maintenance access.
Sketch the interior layout now — not after framing. Mark where shelves, a workbench and the door swing will go. Deciding door width at this stage (a 90 cm clear opening handles most ride-on mowers) prevents expensive adjustments later.
| Planning decision | Why it matters early |
|---|---|
| Footprint & height | Drives timber quantities and permit requirements |
| Door position & width | Determines wall framing layout |
| Roof pitch | Affects headroom, drainage and material choice |
| Interior layout | Positions blocking for shelf and workbench fixings |
The foundation keeps the structure level and cuts off rising damp — the main enemy of wooden floor joists. Three proven options:
Whichever base you choose, floor joists must be pressure-treated (impregnated) timber. The preservative treatment protects against rot and fungal attack right at the point of greatest moisture exposure. Read our page on what impregnated wood is for a full explanation of how the treatment works and which hazard classes apply to ground-contact use.
Lay 44 × 97 mm (2×4) or 44 × 145 mm (2×6) joists at 400 mm centres and fix 18 mm exterior-grade plywood decking on top. Pre-drill near the ends to prevent splitting.
Frame each wall panel flat on the deck, then tip it up — it is far easier than building in place. Use 44 × 97 mm (2×4) studs at 600 mm centres with a double top plate and single bottom plate. Cut rough openings for the door and any windows 50 mm wider and taller than the finished frame to allow for adjustment.
Brace corners with diagonal noggins or a sheet of OSB/plywood sheathing before you stand the walls up. Once all four panels are plumb and nailed together, add the exterior cladding:
For a deeper look at structural timber grades, see our guides on construction timber and SLS/CLS timber.
A pent (lean-to) roof with a 15° pitch is the simplest to frame and sheds Swedish rain reliably. A apex (gable) roof adds headroom and a more classic look but requires cut rafters or pre-made trusses. Either way, allow at least 300 mm overhang on the sides and 200 mm front and back to protect the cladding.
Cover the roof deck with 12 mm exterior plywood, then either bitumen shingles (easy to cut and nail) or corrugated steel sheeting (faster and extremely durable in wet climates). Fix all fixings with hot-dipped galvanised or stainless nails — standard bright steel will stain the timber and fail within a few years.
Hang the door on 100 mm heavy-duty strap hinges. A hasp-and-staple with a padlock is the standard closure for garden sheds; add a bolt on the inside if you plan to work in the shed with the door shut. Fit a small opening window on the side opposite the door for cross-ventilation — this also prevents tool handles warping in a stuffy interior.
Finish all exposed timber with a penetrating exterior wood stain or microporous paint. Two coats on bare timber before assembly, one coat on joins after. Our guide on the best way to stain wood covers product selection and application in detail. Also explore how shed projects compare with building a wooden deck and a wooden carport — similar skills, very different structural demands.
Once the shed is done, the garden itself deserves the same quality of thinking. A well-chosen bench near the shed entrance gives you somewhere to sit after a morning of work.
In Sweden, outbuildings up to 15 m² can generally be built without a building permit (attefallsåtgärd), but you must notify your municipality. Rules vary by municipality and by how close the shed is to a property boundary — always check with your local byggnadsnämnd before you start.
Always use pressure-treated (impregnated) timber for floor joists and the bottom wall plate. These are the areas most exposed to ground moisture. Untreated structural timber will rot within a few years in a Swedish climate.
Start by listing everything you want to store, then add 20% for future growth. A 3 × 3 m shed handles a lawnmower, two bikes and standard garden tools. If you also want a small workbench, consider 3 × 4 m or 3 × 5 m.
A pent (lean-to) roof is easiest to build and drains well. An apex roof adds usable headroom and suits larger sheds. Avoid flat roofs — they require a proper waterproofing membrane and regular maintenance to prevent leaks.
Use pressure-treated timber for all structural elements in contact with the ground or deck. Apply a quality exterior wood stain or microporous paint to all cladding — two coats minimum. Re-coat every 3–5 years depending on exposure. For added insect resistance, choose a stain that contains a preservative biocide.
