Lawful Development Certificate

Permitted Development Eligibility Assessment

Based on our analysis of the property at 14 Rosewood Terrace, Wimbledon, London SW19 4PQ, the proposed single storey rear extension is likely to qualify as permitted development under the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended), specifically under Schedule 2, Part 1, Class A.

Key Findings

• Property type: Semi-detached dwelling — permitted development rights are available subject to standard conditions and limitations.
• Conservation Area / Listed Building: The property is not within a Conservation Area and is not a Listed Building. No additional restrictions from designated status apply.
• Article 4 Directions: No Article 4 Directions are in force that would remove or restrict the householder permitted development rights applicable to this proposal.
• Previous extensions: A Certificate of Lawfulness was granted in 2018 for a rear dormer loft conversion. The cumulative impact of previous enlargements must be considered when calculating remaining permitted development allowance.

Dimensional Limits Under Class A

For a semi-detached dwelling, the following limits apply to a single storey rear extension under Class A:

• Maximum depth from the original rear wall: 3 metres (or up to 6 metres under the Larger Home Extension scheme with prior approval from the LPA)
• Maximum height: 4 metres
• Maximum eaves height: 3 metres (if within 2 metres of a boundary)
• The extension must not extend beyond the rear wall of the original dwelling by more than half the width of the original dwelling
• Total ground coverage (including outbuildings) must not exceed 50% of the total curtilage area

The current developed area stands at 42% of the plot, leaving adequate headroom for a modestly sized single storey rear extension within the 50% curtilage coverage limit. We recommend confirming exact dimensions with your architect to ensure compliance before submitting the LDC application.

These are the key fields you will need to complete on the Planning Portal application form. Copy and paste the suggested text directly into the form.

Supporting Statement Guidance

While not strictly required for an LDC application, a well-prepared supporting statement significantly increases the likelihood of a smooth approval process. The statement should clearly demonstrate that the proposed development falls within the scope of permitted development rights.

Recommended Content

Your supporting statement should address the following points:

• Site description: Briefly describe the property, its location, and the surrounding residential character of Rosewood Terrace.
• The proposal: Set out the precise dimensions of the proposed extension — depth from the original rear wall, maximum height, eaves height, and width. Reference the proposed drawings by drawing number.
• Compliance with Class A: Systematically work through each condition and limitation in Class A, demonstrating that the proposal satisfies each one. This includes the depth limit (3m for a semi-detached, or 6m under the Larger Home Extension scheme), the height limits, the boundary setback requirements, and the 50% curtilage coverage threshold.
• Previous development: Acknowledge the 2018 lawful development certificate for the rear dormer and confirm that the cumulative enlargement remains within permitted thresholds.
• Materials: State that materials will be of similar appearance to the existing dwelling, as required by the condition in Class A.

We recommend keeping the statement concise and factual, with clear cross-references to the relevant legislation. A well-structured statement typically runs to 2–3 pages and can help the case officer process your application more efficiently, reducing the risk of delays or requests for further information.

Your LDC application needs to include accurate, scaled drawings. Click each plan type below to see exactly what it should contain, where to get it, and what mistakes to avoid.

Planning History Analysis

The planning history for 14 Rosewood Terrace reveals a property with a modest but relevant development history. Three previous applications have been submitted, providing useful context for the current LDC proposal.

The most significant entry is the 2018 Certificate of Lawfulness for a rear dormer loft conversion with rooflights, which was approved under delegated authority. This confirms the council has previously accepted that permitted development rights apply to this property, and it establishes a baseline for assessing cumulative development. The approved loft conversion added approximately 35m³ of roof volume, which is within the 50m³ limit for semi-detached properties.

The 2023 withdrawn householder application for a single storey rear extension is particularly noteworthy. The application was withdrawn by the applicant before a decision was reached — this does not indicate a refusal and the council made no adverse findings. It is possible the applicant chose to pursue the LDC route instead, or revised the scheme. The proposed dimensions (3.5m depth, 3.0m max height) in that earlier application would have been within permitted development limits for Class A.

The 2015 approval for a single storey side extension and vehicular crossover demonstrates the council’s willingness to approve sympathetically designed extensions on this street. The 2009 window replacement is minor and does not affect permitted development entitlements.

Overall, the planning history is favourable for the current proposal. There are no refusals, enforcement actions, or conditions that would restrict permitted development rights at this property.

Application Checklist

Ensure you have prepared all of the following before submitting your LDC application to the London Borough of Merton:

• Completed application form — Use the standard LDC application form available on the Planning Portal. Select “Proposed use or development” (Section 192).
• Location plan at 1:1250 or 1:2500 scale — with the site outlined in red and based on current OS mapping.
• Site plan (block plan) at 1:200 or 1:500 scale — showing the proposed extension footprint, distances to boundaries, and the TPO-protected oak tree.
• Existing floor plans and elevations at 1:50 or 1:100 scale — accurately showing the current layout of the dwelling.
• Proposed floor plans and elevations at 1:50 or 1:100 scale — clearly showing the extension with all key dimensions annotated.
• Supporting statement — demonstrating compliance with Schedule 2, Part 1, Class A of the GPDO 2015 (recommended but not mandatory).
• Application fee — £103 payable via the Planning Portal.
• Photographs — While not required, photographs of the existing rear elevation and garden context can help the case officer assess the application (recommended).

The London Borough of Merton aims to determine LDC applications within 8 weeks of validation. Ensure all documents are clearly labelled with drawing numbers and the property address to avoid delays in validation.