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Merton · Garage Conversion · 2026

Garage Conversion Planning Permission in Merton: 2026 Guide

Merton has significant conservation area coverage at 15%, and several streets are covered by design guidance that affects garage conversion applications. Householder approvals in Merton run at around 81% with an average decision time of 9 weeks.

Verdict
May be permitted development

A garage conversion in Merton can often be permitted development when it stays within size and design limits and no local constraint applies to your address. Always confirm at address level.

Planning Constraints in Merton for Garage Conversion

Conservation area coverage
15%
Approval rate (Merton)
81%
Avg. decision time
9 weeks
Article 4 directions
0
Wimbledon conservation areas
Basement SPD (2017) applies
Wimbledon Common MOL

Permitted Development Rules

Converting an integral or attached garage to habitable space is generally permitted development under GPDO Schedule 2, Part 1, Class G, provided no extension or external enlargement is involved.

  • Conversion must be to the interior only — no enlargement of the building.
  • External alterations (e.g. replacing the garage door with a window) are PD only if materials and design match the house.
  • The garage must have been part of the original house or a lawfully implemented extension.
  • Article 4 directions can remove this PD right in specified parking zones.
  • Off-street parking provision may be a planning condition on new-build estates.

Read the full garage conversion planning guide for the national rules and application process.

Recent Garage Conversion Decisions in Merton

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

Frequently Asked Questions

Do I need planning permission for a garage conversion in Merton?

In Merton, the answer depends on whether your property sits in a conservation area (15% of the borough), is listed, or falls within an Article 4 direction. Most garage conversion 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 garage conversion in a conservation area in Merton?

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

How long does a garage conversion application take to decide in Merton?

Merton Council currently averages around 9 weeks for householder applications. Complex garage conversion 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.

Do I need planning permission to convert a garage in Merton?

Most garage conversions in Merton are permitted development provided the work is internal and any new windows or doors match the house. Article 4 directions in parts of the borough can remove this right — always verify at address level.

Next step

Check your specific address in Merton

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