Permitted development in the UK: the complete London homeowners guide

Contents

• What is permitted development?
• Who can use it in London ‐ and who cannot
• Permitted development vs prior approval
• Rear and side extensions under PD
• Loft conversions and roof works
• Outbuildings, garden rooms and home offices
• Driveways and front gardens: the 5 m² rule
• Solar, heat pumps and green upgrades
• Upward extensions (additional storeys)
• Article 4 and conservation areas
• Lawful Development Certificates
• Fees and timelines in 2025
• Building Regulations and Party Wall
• Quick takeaways
• FAQs
• Conclusion
• References and Further Reading

What is permitted development?

Permitted development (PD) is a national planning permission that allows many common home improvements to proceed without a full planning application, provided your project meets specific limits and conditions. In practice, PD can streamline smart upgrades to London houses — extensions, lofts, outbuildings, solar — while keeping quality safeguards through measurements, materials and siting rules. PD does not remove the need to comply with Building Regulations or other consents.

Who can use it in London ‐ and who cannot

PD rights principally apply to dwelling houses. Most flats and maisonettes do not benefit, and listed buildings are outside typical householder PD. If your home sits on designated “article 2(3) land” ‐ such as a conservation area ‐ some rights are restricted. Always check if an Article 4 Direction has removed specific PD on your street.

Permitted development vs prior approval

Some PD classes require you to obtain the council's prior approval before starting work. This is not a full planning application; instead, the authority assesses defined impacts (for example, neighbour amenity or external appearance) within a set period. Typical examples: larger single-storey rear extensions and upward extensions. If prior approval is silent after the deadline, your development may proceed ‐ but do not start before the decision period ends.

Rear and side extensions under PD

Under PD, many London homes can build single-storey rear extensions up to 3 m deep for attached houses and 4 m for detached homes, subject to height, eaves, and materials matching conditions. The “larger home extension” route allows up to 6 m (attached) or 8 m (detached) provided you secure prior approval through the neighbour consultation scheme. Side extensions are typically single-storey, no greater than 4 m in height and no more than half the width of the original house. Wrap-around schemes must be designed so each element complies in its own right, or they will fall outside PD.

Loft conversions and roof works

Loft conversions and dormers can fall under PD when volume limits, set-backs and height rules are met. Rear-roof dormers are common in London terraces; front dormers are more sensitive and often excluded under PD, particularly in conservation areas. Materials should be similar in appearance to the existing house and any side-facing windows at first floor and above should be obscure-glazed and non-opening below 1.7 m internal height.

Outbuildings, garden rooms and home offices

PD allows many outbuildings within the curtilage if they are for “incidental” purposes ‐ think gym, studio or store ‐ not self-contained accommodation. Respect total coverage limits, heights (with tighter rules near boundaries), and ensure garden rooms remain ancillary. In London, careful massing, materials and positioning mitigate neighbour impact while preserving usable garden.

Driveways and front gardens: the 5 m² rule

Converting front gardens to parking is PD where the area is 5 m² or less, or where you use a permeable surface or permeable sub-base with suitable drainage. Non-permeable surfacing over 5 m² that sheds water to the highway typically needs planning permission. Don't forget that a dropped kerb is a separate highways consent. For many London plots, resin-bound or permeable block systems balance kerb appeal and compliance.

Solar, heat pumps and green upgrades under PD

Roof-mounted solar is generally PD subject to size, siting and glare conditions. Air source heat pumps can be PD if they meet siting and MCS-020 noise criteria. Current guidance works to an effective 37 dB LAeq,5min at the assessment point to protect neighbours. Placement, acoustic screening and selecting a quieter unit help achieve compliance on tight London plots. As an added incentive, qualifying energy-saving installations are 0% VAT until 31 March 2027, improving payback on solar and heat pumps.

Upward extensions (additional storeys)

PD allows additional storeys on some houses via Class AA, but it is always subject to prior approval. Expect checks on design, height parameters, neighbour amenity and transport/highways impacts. In period terraces, townscape sensitivity often drives design refinements; early 3D massing helps demonstrate a considerate approach.

Article 4 streets and conservation areas

Many inner-London neighbourhoods sit within conservation areas where PD rights are restricted, and Article 4 Directions may further remove specific rights such as changes to front elevations or roofs. Your solicitor's searches or the borough website will confirm if you are affected. If in doubt, ask for written confirmation before committing to works.

Lawful Development Certificates: planning certainty

An LDC is a formal decision that your proposed (or existing) development is lawful for planning purposes. It is optional but strongly recommended before committing to structural works, especially in conservation areas or where measurements are tight. LPAs aim to determine LDCs in around 8 weeks. Think of it as your insurance policy against future enforcement or conveyancing headaches.

Fees and timelines in 2025

From 1 April 2025 in England the householder planning application fee is £528. Prior approval fees vary by class (e.g., larger home extensions), while an LDC for proposed development is generally half the equivalent planning fee. Build this into your budget alongside surveys and drawings, and allow for statutory decision periods: prior approval windows (e.g., 42 days for larger rear extensions) and the LDC's 8-week target.

Building Regulations and the Party Wall Act

PD never replaces Building Regulations. Expect energy performance under Part L and summer comfort under Part O for new residential spaces, plus structural, fire and drainage compliance. Where you cut into party structures or build near boundaries, the Party Wall etc. Act 1996 may require notices and agreements. Early neighbour dialogue is good practice in London's dense streets, reducing risk to programme.

Quick takeaways

What to remember

• PD is rule-based permission for houses; flats and listed buildings are mostly excluded.

• Some PD needs prior approval ‐ do not start works until the decision/expiry date.

• An LDC provides binding certainty; target determination is around 8 weeks.

• 2025 fees are updated; plan for £528 if you pivot to full householder consent.

• Use permeable front paving, quiet heat pumps and fabric upgrades to meet rules and reduce running costs.

FAQs

Do flats have permitted development rights?

Generally no. Most PD rights are for houses. If you're in a flat or maisonette, seek specific advice.

What is prior approval ‐ and when do I need it?

It's a targeted consent used by some PD classes (e.g., larger rears; upward extensions) to check defined impacts before you build.

Should I get an LDC?

If you want certainty, yes. It is optional but recommended where dimensions are tight, in conservation areas, or before exchange of contracts.

How big can I extend at the rear?

Typically up to 3 m (attached) or 4 m (detached) as straight PD. Larger depths up to 6 m/8 m require prior approval.

Is front garden paving PD?

Yes if you use permeable systems or keep it ≤5 m², otherwise permission is likely needed.

Are heat pumps allowed under PD?

Often, if MCS-020 noise calculations pass and siting/size rules are met. Placement and screening are key on tight sites.

Does PD override Building Regulations?

No. You must still comply with Parts L, O and other applicable regulations.

What are 2025 fees?

Householder applications are £528; prior approval and LDC fees differ by class and basis.

What if my borough has an Article 4 Direction?

Some PD rights may be removed locally. Check your address and, if needed, apply for planning permission instead.

Any tax reliefs for green upgrades?

Yes. Qualifying energy-saving installations are 0% VAT until 31 March 2027.

Conclusion

Used strategically, permitted development is a powerful route to add space and value to London homes without the cost and wait of full planning. The key is precision: measure twice, design once, and confirm eligibility early ‐ via prior approval where required or an LDC for certainty. Align your scheme with Building Regulations and neighbour relations, and you will enjoy a smoother build and a better result.

If you want an expert partner to translate your brief into a compliant, beautiful design, Better Homes Studio can audit your address, optimise the layout within PD, prepare drawings, and manage any LDC or prior approval ‐ so you can get building with confidence.

References and Further Reading