Do I Need Planning Permission for Decking?

Most garden decking in England does not need planning permission, provided it is in the rear garden, not raised more than 0.3 metres above ground level, and combined with other structures does not cover more than half the curtilage. Where decking is raised higher — creating an elevated platform or terrace — it is treated as a veranda or balcony under the permitted development rules, and planning permission is likely required.

The 0.3 metre height threshold is measured from the original ground levelto the top of the decking surface. This is roughly the height of a standard kerbstone. Ground-level decking that sits on joists or a simple frame usually comes in well below this limit. However:

• Decking built over a sloping garden that is level at one end but raised significantly at the other end — even if the upper end is close to ground level — is assessed at its highest point
• Decking with a step up from the house level may push the far edge above 0.3 m if the garden slopes away from the house
• Adding a balustrade or railing does not in itself determine the classification — the deck surface height is what matters for planning; railings may still be needed for safety under building regulations

If any part of the deck surface is more than 0.3 metres above original ground level, the structure is treated as a veranda or raised platform and planning permission is required.

• Decking is in the rear garden and not forward of the principal elevation of the house
• The deck surface is not raised more than 0.3 metres above the original ground level at any point
• Combined with all other structures (sheds, extensions, outbuildings), less than 50% of the curtilage is covered
• Property is a house with standard permitted development rights
• The decking is not on designated land where outbuilding rights are restricted for side positions

Front garden decking is subject to different rules. Class E permitted development — which covers outbuildings and garden structures — applies only behind the principal elevation. Decking in the front garden effectively constitutes hardstanding and is assessed under the same rules as driveways and paving: permeable surfaces and smaller areas may be fine, but impermeable hardstanding over 5 m² in the front garden may need planning permission.

Low-level timber decking in the front garden that does not form a solid impermeable surface (gaps between boards) is usually not treated as hardstanding and is unlikely to require planning permission, but the front-of-principal-elevation rule can still apply.

The 50% curtilage coverage rule applies to all outbuildings and garden structures combined. Decking is included in this calculation if it constitutes a significant structural platform. While ground-level decking is often not counted as a “building” for planning purposes, substantially elevated decking with structural supports may be.

If decking is built close to a boundary and raised, it may cause amenity or privacy impacts on neighbours. Even where planning permission is not required, councils can receive complaints and investigate whether the development is genuinely within permitted development limits. At over 0.3 m height near a boundary, it is almost certain to need planning permission.

• Decking surface raised more than 0.3 metres above original ground level — treated as a veranda, balcony or raised platform
• Decking in the front garden that exceeds permitted development thresholds
• Property is a flat or maisonette
• Property is a listed building
• Permitted development rights removed by an Article 4 direction or planning condition
• Total coverage of the curtilage by structures (including decking) exceeds 50%

In conservation areas, rear decking at or below 0.3 m may still qualify as permitted development for houses. However, decking to the side of the house on designated land is not permitted development. Elevated decking, which requires planning permission anyway, will be assessed for its visual impact on the character of the conservation area. Traditional materials — such as hardwood — are more likely to be supported than composite decking with a modern appearance in a historic setting.

Low-level decking (under 0.3 m) is unlikely to need building regulations approval for structural reasons alone, though electrical connections to outdoor lighting on the decking must be carried out by a registered electrician (Part P). Decking over 0.6 m above ground may require building regulations approval for structural safety, and any decking attached to the house structure may need approval as part of the house rather than as a standalone structure.

Regardless of regulations, all raised decking should be designed with appropriate joist spacing, post foundations and corrosion-resistant fixings. Decking boards should have a non-slip surface, particularly in shaded or north-facing gardens where algae growth is common.

The choice of decking material affects appearance, maintenance, longevity and cost:

• Pressure-treated softwood: The most common and affordable option. Requires annual oiling or staining. Lifespan 15–25 years if well maintained.
• Hardwood (e.g. Ipe, Garapa, Bangkirai): Naturally durable and resistant to rot. More expensive but lower maintenance. Check FSC certification.
• Composite (wood-plastic composite, WPC): Low maintenance, consistent appearance. More expensive upfront but no oiling required. May get hot in direct sun.
• Aluminium: Extremely durable, non-slip profiles available. Most expensive option. Common in commercial settings.

Ground-level treated softwood decking: £80–£150 per m² installed. Composite decking: £120–£200 per m² installed. Raised decking with structural framing: £150–£250+ per m². A 25 m² rear deck in treated softwood: approximately £2,000–£4,000. If planning permission is required (raised decking): a householder application costs £258 plus architect drawings (£400–£1,000).

Does decking count as garden coverage for planning purposes? Ground-level decking is not always counted as a “building” for the 50% curtilage calculation, but elevated structural decking may be. If in doubt, assume it counts and check whether you are under the 50% limit.

I have a raised terrace at the back of my house — is that different from decking? Not meaningfully for planning purposes. A raised terrace, elevated platform, or balcony at the rear are all treated the same way: over 0.3 m requires planning permission.

My garden slopes significantly. How is the 0.3 m measured? From the original ground level at each point beneath the decking to the deck surface above it. If the garden drops away steeply, the far end of level decking may be well above 0.3 m even though it looks ground-level from the house.