Retrospective Planning Applications for Raised Decking

Raised decking is permitted development only if it is no more than 30 centimetres above ground level. Anything higher — including any railings or balustrades — needs planning permission. The biggest issue with retrospective decking applications is overlooking of neighbouring gardens and habitable rooms, which is usually mitigated through screening, planting or repositioning. Most retrospective decking cases are approvable when these concerns are addressed in the application.

The 30cm rule

The Town and Country Planning (General Permitted Development) (England) Order 2015 treats raised platforms and decking under Class E. The key limit is straightforward but easily missed: the surface of the decking, including any balustrades or rails, must not exceed 30 centimetres above ground level for the structure to fall within permitted development rights. Anything higher requires full planning permission.

Other PDR limits also apply:

The decking, combined with other garden buildings and structures, must not cover more than 50% of the garden area excluding the original house footprint
It must be for purposes incidental to the enjoyment of the dwelling
It must not be in a conservation area, AONB, World Heritage Site or National Park (where stricter rules apply)

Why decking applications get flagged

Raised decking is one of the most common neighbour-complaint issues we see. The reason is simple: a 60cm or 80cm raised platform suddenly puts the user at eye-level with first floor windows in the neighbouring property and looking straight into the garden next door. Even a modest deck can fundamentally change the privacy of the surrounding plots. Council enforcement teams take overlooking objections seriously.

Submission requirements

What a decking application needs

Application form — correct form, clearly marked as retrospective
Site location plan — OS-based, scale 1:1250
Block plan — showing the position of the deck, the surrounding gardens, and any neighbouring habitable windows
Existing and proposed elevations and floor plans — with full dimensions, materials and the platform height clearly annotated
Photographs — showing the deck, the surrounding context and any privacy mitigation already in place
Planning statement — engaging Local Plan policies on amenity, privacy and garden character; addressing the overlooking question directly
Privacy mitigation proposals — trellis, planting, obscure screens, repositioned seating

Common issues and how to address them

Overlooking and privacy. The single biggest issue. Mitigation: screening trellis, planted boundaries, repositioning seating away from neighbour-facing edges, restricting hours of use through a planning condition.
Visual impact and overdevelopment. Where the deck is large and dominates the garden, propose modifications: reducing the area, lowering the platform where possible, or splitting the deck into smaller sections.
Drainage and ecology. Decking near trees, wildlife habitats, or in flood-prone areas may raise ecological or drainage concerns. Consider a short ecology note and confirmation that the decking is permeable or has been built with adequate drainage.
Material and design. Match the deck's materials and finish to the property and surrounding gardens. Painted deck stains in dark, recessive colours read better than bright timber.

The honest summary

Raised decking cases are approvable in most situations, but they require honest engagement with the overlooking question. A planning statement that pretends the deck has no impact on neighbours will be refused. A planning statement that proposes structured mitigation usually succeeds.

Frequently asked questions

Is decking under 30cm always permitted development?

Generally yes, provided the property is a dwellinghouse (not a flat) and is not in a conservation area, AONB or other protected designation. Note that the 30cm includes the surface of the decking — if you have any railings, the railings themselves may push the structure beyond the limit.

How do I prove the height of my deck?

Measure from the natural ground level adjacent to the deck to the top surface of the deck. A site survey or simple measured photographs with a ruler against the structure are usually enough.

Will the council make me reduce the height of my deck?

Possibly. Where the case officer takes the view that the deck causes meaningful overlooking that cannot be screened, they may negotiate a reduction in height as a condition of approval. This is preferable to a refusal.

Do I need a fence or screen around my deck?

Not for safety in most cases (fall heights are usually below the building regulations threshold). But for planning purposes, screening on the neighbour-facing edges is often what gets the case approved.

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