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For homeowners dreaming of a rear extension, loft conversion, or a complete property overhaul, the first hurdle isn’t the builder it’s the paperwork. The question is always the same: “Do I need Permitted Development (PD) or a full Planning Application?”
Getting this wrong can result in expensive delays, forced demolition, or a property that’s hard to sell later. As an award-winning RIBA Chartered Practice specialising in residential developments across Essex, Kent, and London, we guide clients through these complex local authority rules every day. This guide cuts through the confusion.
1. Permitted Development (PD): The Planning Fast Track
Permitted Development (PD) rights are a national grant of planning permission established by the UK Government, allowing you to undertake certain common residential building works without needing a full planning application. This saves time and cost, but only if your proposal adheres strictly to the rules.
The PD Checklist for Houses
| Area of Extension | Standard PD Limit (Must be a ‘House’, not a flat) |
| Rear Extension (Detached) | Up to 4 metres from the original rear wall (Up to 8m with Prior Approval). |
| Rear Extension (Semi-Detached/Terraced) | Up to 3 metres from the original rear wall (Up to 6m with Prior Approval). |
| Height | Maximum total height of 4 metres; eaves must not exceed 3 metres if within 2m of the boundary. |
| Coverage | The extension cannot cover more than 50% of the land surrounding the ‘original house’. |
| Materials | Must be similar in appearance to the existing dwelling’s exterior. |
The Crucial Safety Net: The Lawful Development Certificate (LDC)
Even if your plans fall perfectly within the PD limits, we strongly advise applying for a Certificate of Lawful Proposed Development (CLPD).
- What it is: A formal, legally binding document issued by your Local Planning Authority (LPA).
- Why it’s essential: It provides absolute legal proof that the extension was lawful at the time of build. This is critical for conveyancing and peace of mind when you eventually sell the property.
2. Full Planning Permission (FPP): When the Rules are Exceeded
If your architectural vision requires a design that exceeds the size limits of PD, or if your property is subject to specific planning controls, a Full Planning Application is required.
When a Full Application is Mandatory
- Designated Areas: If your property is within a Conservation Area, a National Park, or is a Listed Building. In these locations, Permitted Development rights are often removed or significantly restricted (sometimes via an Article 4 Direction).
- Two-Storey Extensions: These are far more restricted than single-storey projects and usually require FPP.
- Any Work on Flats or Maisonettes: These property types do not have standard Permitted Development rights.
The Architect’s Value in the Planning Process
This is where the expertise of Connor Ferris Architects is invaluable. We don’t just submit drawings; we manage the planning strategy using our BUILD Framework to persuade the LPA:
- We conduct thorough pre-application research into [e.g., Chelmsford Council, Kent County, or specific London Borough] policies, addressing potential impact issues like “Rights to Light” or “Overlooking” upfront.
- We craft a Bold and Innovative design narrative, detailing how the new structure enhances the home and surrounding area, leading to the highest chance of approval.
⚠️ MANDATORY UK COMPLIANCE: Building Regulations
The most common mistake homeowners make is confusing planning consent with technical approval.
All building work in the UK must comply with Building Regulations. This covers:
- Structural Integrity: Ensuring the extension won’t collapse.
- Fire Safety: Including means of escape and fire resistance.
- Energy Efficiency (Part L): The UK has ongoing regulatory uplifts to reduce carbon emissions. Your extension must meet high standards for insulation, glazing (U-values), and air tightness.
- Ventilation (Part F): Ensuring adequate airflow and air quality.
As a RIBA Chartered Practice, our technical design stage includes preparing the detailed drawings, specifications, and calculations necessary to satisfy Building Control (either Local Authority or Approved Inspector). This ensures your finished project is not only beautiful but legally compliant and safe.
Let Our Expertise Guide Your Build
Whether you are seeking to utilise your existing Permitted Development rights or require a complex Full Planning Application for a bespoke design, Connor Ferris Architects provides the peace of mind and technical assurance you need.
