Garden Sheds: Sizes, Bases & Cost

A garden shed is one of the most practical and cost-effective improvements you can make to a UK property. Whether you need garden tool storage, a workshop, home office, or simply a place to keep bikes out of the rain, the right shed, on a solid base, will last 15–30 years with modest maintenance. This guide covers sizes, materials, base types, costs, and the planning rules you need to know.

Typical Shed Sizes

Shed dimensions are usually quoted in imperial feet in the UK market, even though manufacturers sometimes give metric equivalents. Common footprints are:

The 8×6 ft shed is the sweet spot for most UK gardens, large enough to store a lawnmower, garden tools, and modest DIY equipment, yet small enough to avoid any planning complications on most plots.

Materials Compared

Timber (pressure-treated softwood), by far the most popular choice in the UK. Usually tongue-and-groove or overlap cladding on a timber frame. Modern pressure-treated timber (tanalised or similar) resists rot for 15–25 years when properly maintained. Requires treatment with a wood preservative every 2–3 years. Aesthetically flexible, can be painted or stained.

Timber (log cabin style), interlocking horizontal logs, typically 28–44 mm thick. More substantial and better insulated than standard sheds. Usually sold as garden rooms or workshops. Higher cost but better suited to year-round use.

Metal (steel or galvanised), cheaper at the entry level, lighter to handle, fire-resistant, and pest-proof. However, steel can rust at joints and fixings over time, condensation inside is common without added insulation, and they are louder in rain. Popular for secure cycle storage or basic garden tool storage.

Plastic (PVC or resin), virtually maintenance-free, won’t rot or rust, easy to clean. Limited size range; less attractive than timber; some cheaper models lack structural rigidity. Good choice for low-maintenance storage of garden furniture or equipment in smaller sizes.

Shed Costs (Supply Only, 2026)

Flat-pack delivery is standard; assembly is either DIY or can be contracted to the supplier or a local handyman. Assembly of an 8×6 ft shed typically takes 4–8 hours for two people.

Shed Base Options

A proper base is essential. A shed sitting directly on soil will rot from the bottom within a few years, void any manufacturer guarantee, and become unstable. The main options are:

Concrete slab, the most durable option. Typically 100 mm thick C20 concrete on a 50–75 mm compacted hardcore sub-base. Should extend 75–100 mm beyond the shed footprint on all sides. For an 8×6 ft shed this means a slab of approximately 2.6 m × 2.0 m. Cost supply and fit by a groundworker: £350–£600 depending on access, ground condition, and local rates.

Paving slabs on sand, a good budget alternative if the ground is reasonably firm and level. 50 mm bedding sand on compacted sub-base, with 600×600 mm slabs (or similar). Can be DIYed. Cost supply and fit: £180–£350 for an 8×6 ft footprint. Slabs must be laid level, use a spirit level throughout.

Timber bearer frame, pressure-treated timbers (typically 100×50 mm CLS or sleepers) laid on compacted hardcore. Cheaper to install than concrete, allows some adjustment, and works well on sloped ground. The shed floor frame bears directly on the timbers. Cost: £120–£280 for materials; add labour if not DIY.

Plastic grid base, interlocking polypropylene grid panels on compacted ground. Quick to install, drains freely, cheap (around £60–£150 for an 8×6 ft area). Works adequately for light loads but may flex under heavy point loads (e.g. a loaded chest freezer).

Total Installed Cost: 8×6 ft Example

Electrics (if wanted) are notifiable if the circuit runs from the house consumer unit: either a registered competent person installs and self-certifies the work, or it is notified to building control before it starts.¹ A simple garden cable supplying a single socket and light typically costs £250–£500 fitted, including an RCD-protected outlet.

Planning Permission

In England, garden sheds are classed as permitted development (PD) under Class E of the Town and Country Planning (General Permitted Development) (England) Order 2015, subject to the following conditions:

• The shed must be within the curtilage of the dwelling (your garden)
• It must not be in front of the principal elevation (front garden of the house, or side elevation that faces a road)
• Maximum eaves height of 2.5 m and maximum overall height of 4 m (dual-pitch roof) or 3 m (any other roof)
• The combined footprint of all outbuildings must not exceed 50 % of the garden area
• In a Conservation Area or National Park, PD rights are more restricted, outbuildings over 10 m² or forward of the principal/side elevation require planning permission

Wales, Scotland, and Northern Ireland have similar but not identical PD rules, check with your local planning authority if in any doubt.

Listed buildings have no PD rights for outbuildings, always apply for Listed Building Consent.

Security

A garden shed is a common target for theft. Practical security measures:

• Quality hasp and padlock, minimum grade 4 padlock to BS EN 12320:2021, fitted with a hardened steel hasp bolted through the door frame with coach bolts (not screws)²
• Anchor point, a ground or wall anchor inside the shed allows bikes and tools to be secured with a chain
• Alarm, a simple battery PIR alarm (£20–£60) inside the shed can deter casual theft
• Consider a smart camera at the shed entrance, mains or solar-powered, connected to a home Wi-Fi network or mobile data

Inform your home insurer that you have a shed and that it contains high-value items (bicycles, power tools). Cover under your buildings/contents policy may have limits for outbuildings, typically £1,000–£3,000, and will require a minimum padlock standard.

Maintenance

Timber sheds last longest with:

• Annual treatment with a quality wood preservative or shed stain
• Clear gutters if the shed has them, blocked gutters overflow down the wall and accelerate rot at the base
• Ventilation, most sheds benefit from keeping small ventilation gaps at eaves level to reduce condensation; a vapour-permeable felt underlay under the roof boards also helps
• Check felt roof annually and re-felt when it begins to split or lift; roofing felt typically lasts 5–10 years before replacement is needed (cost: £60–£150 for materials on an 8×6 ft shed, DIY)