Flats and Maisonettes in Merton

A staggering percentage of planning enforcement cases in the London Borough of Merton stem from a single, critical misunderstanding: the assumption that flats possess Permitted Development (PD) rights. They do not.

If you own a purpose-built apartment in Wimbledon, or a converted ground-floor Victorian maisonette in Colliers Wood, you are legally stripped of the automatic right to extend externally.

The 'Zero PD' Reality

Operating a property classified as a flat requires a fundamentally different planning strategy:

• Every External Change Wants Planning: Because flats lack PD rights, changing a single, tired timber window frame to a modern UPVC unit requires a Full Planning Application. Adding a tiny rear extension, swapping a door, or painting the front facade requires formal council consent. Attempting these under the radar is illegal.
• Acoustic Separation and Stacked Living: If you are reconfiguring the interior layout of a flat (e.g., knocking down walls to create a large open-plan kitchen), Merton’s Building Control and Planning departments will actively scrutinize the "vertical stacking." If your new hard-floored kitchen sits directly above the bedroom of the flat below, you will routinely be forced to install incredibly dense, expensive acoustic flooring membranes to meet sound transmission regulations.
• Amenity Space Loss: Ground-floor flats often desperately seek to extend into the shared or private rear garden. Planners aggressively defend private outdoor amenity space for flats. If a rear extension consumes more than 50% of the flat's allocated garden, it will be refused as an unacceptable loss of living standard.

Official Merton Council Resources

Before committing to any major architectural project, we strongly advise cross-referencing your ambition directly with the local authority. The following links provide direct access to Merton Council's live planning portals and heritage registries:

• Merton Planning & Building Control Portal
• Search Live Merton Planning Applications
• Merton Heritage, Conservation Areas & Article 4 Directions

How We Can Help

If you are considering a major refurbishment, extension or basement in Merton, our in-house architectural and construction teams are highly experienced with the specific constraints and policies of this council. Do not leave your planning application to chance—our Planning & Permissions and Architecture services are explicitly designed to handle strict London authorities from initial conceptual design through to final, legal consent.

Once permission is secured, our Refurbishment & Interiors division carefully manages the execution, guaranteeing the design integrity is maintained throughout the build phase.

*Published in the Hampstead Renovations Planning Guide Collection — delivering expert design and build strategies for London's most heavily guarded conservation boroughs.*