Quick answer. A 6×4 holds a mower OR a couple of bikes, not both comfortably. An 8×6 is the family-storage sweet spot. A 10×8 gets you into workshop or single-occupant garden-office territory. Above 12×10 you're shopping in steel-garage land. Don't go under 6×4 unless it's a specialist bike locker.
Standard Irish shed dimensions
"6×4" means 6 feet by 4 feet: Irish shed sizes are still quoted in imperial despite metric being everywhere else. Here are the standard sizes converted:
| Size (ft) | Metric (m) | Floor area (m²) | Common use |
|---|---|---|---|
| 6×4 | 1.83 × 1.22 | 2.23 | Bike or mower; tools |
| 7×5 | 2.13 × 1.52 | 3.24 | Bike + mower (tight) |
| 8×6 | 2.44 × 1.83 | 4.46 | Family storage |
| 10×6 | 3.05 × 1.83 | 5.58 | Long-and-narrow option |
| 10×8 | 3.05 × 2.44 | 7.43 | Workshop / single garden office |
| 12×8 | 3.66 × 2.44 | 8.92 | Larger workshop |
| 12×10 | 3.66 × 3.05 | 11.15 | Two-person garden office |
Remember the planning-permission limit is 25 m² cumulative across all garden buildings, even a 12×10 plus an existing 8×6 puts you over the line. See /planning-permission/.
What fits in each size
6×4 (2.23 m²)
Tight. Two bikes upright with handlebars overlapping, OR a push-mower plus a hedge trimmer plus a few tool hooks. Doesn't fit: a workbench, a sit-on mower, two bikes and a mower, or comfortable walk-around space.
8×6 (4.46 m²)
The family-storage sweet spot. A mower at one end, two bikes hung along one wall, a small workbench at the other end, shelving overhead, plus garden tools. Doesn't fit: four bikes comfortably, or any kind of usable workshop.
10×8 (7.43 m²)
Workshop tier. A 1.5 m workbench, a small bandsaw or table-saw on a stand, tool storage along one wall, room to walk around the bench. Or: a single-occupant garden office with desk, chair, and a small storage rack. Doesn't fit: two-person work setups or a sit-on mower comfortably.
12×8 (8.92 m²) and 12×10 (11.15 m²)
Generous. A 12×10 fits a sit-on mower with room to manoeuvre, or a two-person garden office with desks back-to-back. Past this size you're looking at steel-garage builds: a different supplier set and a different price band. See cost guide.
Headroom: the bonus storage tier
Apex roofs give you 3-4 m³ of storage in the apex space above head height. Hooks and timber rails across the joists let you store bikes overhead, fishing rods, garden canes, ladders, kayaks. Pent-roof sheds lose this: flat or slight-pitch roofs, no apex. If you'll use overhead storage, specify an apex roof at order time.
Door width matters more than you'd think
A single shed door gives 700-800 mm clear opening. A double door gives 1,400-1,600 mm. Things that need a double:
- Sit-on mower or large wheelbarrow
- Motorcycle or moped
- Long boards or sheet material into a workshop
- Comfortable two-person carrying of anything bulky
Specifying a double at order time is usually €70-€120 extra. Retrofitting later is structural and dramatically more expensive.
Footprint vs garden: the visual rule
Rule of thumb: a shed bigger than ~8% of your back garden's area starts to dominate the view. A 10×8 (7.4 m²) on a 50 m² urban lawn is visually too big. It'll feel like the garden is the shed's foreground rather than the other way round. Most people would rather have the same shed as a 12×6 (long-and-narrow) tucked along a fence than a square block in the middle.
The cheapest way to mitigate a too-big shed is a planted screen along the visible side: bamboo or pleached hedging is fast and effective.
Going under 6×4
Don't, unless it's a specialist build. The exception is bike-locker sheds: narrow 5×3 or 6×3 timber bike sheds that sit against a side wall. These are useful as a no-roof-in-your-eye-line second shed for bikes or wheelie-bin storage. As a primary shed: too small for anything else.
Going over 12×10
You're now in steel-garage territory. Look at Steeltech, Adman, Shanette in the supplier directory: these are the operators with stock of 16×10 / 20×10 builds. Cost band €4,500-€8,000+ supplied and fitted. Different planning-permission considerations may apply at the larger end.