Garden & outdoor
How much wood and roofing for a garden tool shed?
Floor, wall and roof m² plus plywood sheets and foundation blocks for a DIY wooden garden tool shed from length, width and height.
Quick answer
A small wooden tool shed is three surfaces: floor, walls, and roof. A 2 × 1.5 × 2.1 m lean-to often needs about 3 m² floor, ~15 m² walls (minus the door), and ~3.5–4 m² roof once pitch and overhang are included — then convert to standard 122×244 cm sheets with spare for cuts.
Advanced settings
Wall cladding
12.9 m²
- Floor area
- 3 m²
- Roof covering
- 3.4 m²
- ≈ 122×244 cm sheets
- 8
- Corner + intermediate posts
- 4
- Foundation pier blocks
- 6
Related garden tools
Walls = perimeter × height − door (~1.8 m²). Roof = floor × roof factor (lean-to ~1.12, pitched ~1.25) for pitch/overhang. Sheets = (floor + walls + roof) × (1 + waste) ÷ 2.98 m². Posts: 4 corners + extras every ~1.2 m on long sides. Pier blocks ≈ every 1 m along both long sides. DIY estimate only — not a structural or planning certificate.
How it works
Enter length, width and wall height. Pick flat/lean-to or pitched roof. The calculator returns cladding areas, sheet count, corner/intermediate posts and concrete pier blocks for a simple raised base. Check local planning rules and wind/snow loads — this is a DIY shopping estimate, not a structural certificate.
A shed rots from the bottom, and always for the same reason. Timber sitting on or near the ground draws moisture up out of the soil and never dries, so the floor and the first twenty centimetres of the walls go long before the roof does — set it on piers with a clear gap underneath so air can move, and use treated timber for everything within a hand's width of the ground. One layout note while you are drawing: on a shed this small, hang the door to open outwards. An inward-opening door needs a clear metre of floor that you were going to fill with the mower.
Frequently asked questions
How many OSB sheets for a 2×1.5 m shed?+
Walls + floor + roof often land around 8–12 sheets of 122×244 cm once waste is included — run the calculator with your height and roof type for the exact count.
Flat roof or pitched?+
A slight lean-to (flat with fall) sheds rain with less timber; a pitched roof needs more covering area but sheds snow better. Use roofing felt or bitumen shingles outdoors.
Do I need a concrete foundation?+
Many DIY sheds sit on pressure-treated skids on concrete pier blocks or paving slabs — level and clear of standing water. Full slabs are more work but very stable.
Kit shed or build from sheets?+
Kits are faster; sheet-built sheds cost less per m² if you already have tools. This calculator sizes the DIY sheet approach — compare kit footprints on Amazon too.
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