This guide explains the benefits of designing within PD guidelines and how to navigate the process effectively.

Material Works have completed a number of permitted development house extensions in London. View our portfolio of recent work, or contact us to discuss your project.

Extending Without Planning Consent

If your proposed extension meets PD criteria, you may not need planning permission. This can speed up the process and reduce uncertainty. However, it’s essential that the design strictly complies with the PD rules; otherwise, your local council could issue an enforcement notice requiring demolition.

To avoid this risk, it’s strongly recommended to apply for a Lawful Development Certificate (LDC), which confirms that your works are lawful under PD.

Lawful Development Certificates (LDC)

An LDC is not a legal requirement, but it provides peace of mind and is often requested by buyers during property sales. You apply via the Planning Portal, and the local authority has up to 8 weeks to make a decision—similar to a standard planning application.

Why Use PD Instead of a Full Planning Application?

While the process of applying for an LDC is similar to a planning application, the key difference is how the proposal is assessed. Planning applications are evaluated based on local policy—which can be subjective and restrictive—while PD rights are based on measurable criteria such as size and height.

Because PD rules are more clearly defined, they offer less room for interpretation and a greater likelihood of approval. This can make it possible to build extensions that might not gain planning approval.

Is Permitted Development Faster?

Yes, generally. Since PD decisions are based on set rules rather than subjective planning policy, there’s less risk in moving ahead with technical design while your LDC is pending. In contrast, it’s best to wait for planning approval before progressing with full applications. This can accelerate your overall timeline.

What Are Permitted Development Rights?

Permitted development rights are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015. The most relevant parts for homeowners are:

Part 1: Development Within the Curtilage of a Dwellinghouse

• Class A: Rear, side, and general alterations. Rear extensions up to 3–4m (or 8m in specific conditions) may be allowed. Two-storey extensions must be at least 2m from the boundary.

• Classes B & C: Roof extensions and alterations (e.g., dormers, roof lights). Limits are usually 40m³ for terraces and 50m³ for detached or semi-detached homes.

• Class D: Porches up to 3m² outside external doors.

• Class E: Outbuildings such as sheds or pools, provided they are detached, don’t cover more than 50% of the garden, and meet height restrictions.

Each class has detailed limitations and conditions that must be met to qualify as permitted development.

Limitations and Restrictions

While PD offers flexibility, it comes with significant restrictions:

• Designated areas: Properties in conservation areas, National Parks, AONBs, World Heritage Sites, and similar protected zones often have restricted or withdrawn PD rights.

• Listed buildings: Most PD rights don’t apply. Planning permission and listed building consent are usually required.

• Flats and maisonettes: These do not benefit from householder PD rights.

• Article 4 Directions: Local authorities can remove PD rights in certain areas (especially conservation zones) requiring a full planning application instead.

• Previously converted properties: Homes converted from other uses (e.g. shops, barns) under PD rules often cannot use further householder PD rights.

In cases where only part of your proposal exceeds PD limits, it may be possible to apply for planning permission just for those elements while using PD rights for the rest.

Need Help?

Material Works has extensive experience in delivering home extensions within PD guidelines across London. View our portfolio of recent work, or contact us to discuss your project.