Garden Room Planning Permission in City of London: 2026 Guide

City of London has one of London's highest conservation area coverages at 80%, which affects many garden room proposals. Householder approvals in City of London run at around 72% with an average decision time of 12 weeks.

Verdict

Depends on constraints

In City of London, whether a garden room needs planning permission depends on specific constraints — conservation area, Article 4, listed status or flood risk. Check your address to see which apply.

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Planning Constraints in City of London for Garden Room

Conservation area coverage

80%

Approval rate (City of London)

72%

Avg. decision time

12 weeks

Article 4 directions

Almost entirely commercial

Very small residential stock

Heritage and viewing corridor protections

Article 4 directions in City of London

• Multiple Article 4 directions affecting office-to-residential conversion and shopfronts

Permitted Development Rules

Outbuildings including garden rooms are permitted development under GPDO Schedule 2, Part 1, Class E, provided they are incidental to the enjoyment of the house.

Maximum height 2.5m if within 2m of any boundary.
Maximum eaves height 2.5m and overall height 4m (dual-pitched roof) or 3m (any other roof).
Must not be forward of the principal elevation fronting a highway.
Total footprint of all outbuildings cannot exceed 50% of the original curtilage.
Must be single-storey.
Use must be incidental to the dwelling — not primary residential accommodation.
Verandas, balconies and raised platforms are not allowed.

Read the full garden room planning guide for the national rules and application process.

Recent Garden Room Decisions in City of London

The CanUBuild checker surfaces real recent applications close to your address — approvals and refusals — so you can see what the planning officers at City of London Corporation have approved for comparable schemes. Nearby precedent is one of the strongest signals for your own chances.

See decisions near your address

Frequently Asked Questions

Do I need planning permission for a garden room in City of London?

In City of London, the answer depends on whether your property sits in a conservation area (80% of the borough), is listed, or falls within an Article 4 direction. Most garden room proposals are permitted development for houses when they stay within GPDO limits and no local constraint applies. Check your exact address with the CanUBuild checker before spending on drawings.

Can I build a garden room in a conservation area in City of London?

Conservation areas in City of London typically remove several permitted development freedoms. For a garden room, the Larger Home Extension route and some external alterations do not apply, so a full householder application is usually required. Planning officers at City of London Corporation assess conservation area proposals against the specific character appraisal for the street.

How long does a garden room application take to decide in City of London?

City of London Corporation currently averages around 12 weeks for householder applications. Complex garden room proposals — particularly those in conservation areas or on listed buildings — can take longer. Prior approval decisions for Larger Home Extensions are typically issued in 42 days.

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Next step

Check your specific address in City of London

Address-level constraints and recent decisions around the corner. No drawings needed.

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