Guide

Building work in a London conservation area: what needs planning permission

KRAMAN Ltd. Published 28 October 2026. Rules checked on 28 October 2026 against the government guidance and legislation listed under Sources below.

A house in a conservation area keeps fewer permitted development rights than a house elsewhere. Roof extensions such as dormers and mansards, side extensions, rear extensions of more than one storey and external cladding all need planning permission. A single-storey rear extension within the limits and rooflights can still be built without an application, unless the council has removed those rights with an Article 4 direction. Flats have no householder permitted development rights anywhere.

What counts as a conservation area

Permitted development rules treat conservation areas as "article 2(3) land", together with National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites. Councils designate conservation areas for their special architectural or historic interest. Leytonstone, Walthamstow Village and Brockley are conservation areas where we work.

To check your street, use the conservation area map on your council website or the national planning data map, and read the council's conservation area appraisal for the area.

What changes inside a conservation area

The table compares the national permitted development rules for a house outside and inside a conservation area. "Permitted development" means the work can go ahead without a planning application if every limit and condition is met.

Every row also carries the usual limits on height, distance to the boundary and how much of the garden can be covered. Permitted development rights may already have been removed by a condition on an earlier planning permission for the house.

Article 4 directions

A council can remove further permitted development rights across a conservation area with an Article 4 direction. Smaller external changes that are normally permitted, for example to windows, doors or front boundaries, then need a planning application too. The direction lists exactly which rights are removed.

Waltham Forest lists the Leytonstone and Walthamstow Village conservation areas among those with an Article 4 direction (Waltham Forest conservation areas). Lewisham has made an Article 4 direction for the Brockley conservation area to keep its original architectural features (Brockley conservation area). See also our pages on building in Leytonstone and Brockley.

Trees

First check whether the tree already has a Tree Preservation Order. If it does, the normal rules for that Order apply: you need the council's consent before any work, unless a statutory exception applies, and giving notice is not enough.

A tree in a conservation area without an Order is still protected. Before cutting down, topping, lopping or uprooting it you must give the council six weeks notice, called a section 211 notice. The work may go ahead earlier if the council consents. If the council does not make an Order and the notice period ends, the work may be done within two years of the notice.

There are exceptions. No notice is needed for a tree whose trunk is no more than 75 millimetres in diameter, measured over the bark 1.5 metres above the ground, or no more than 100 millimetres when it is cut down only to help other trees grow. Work on a dead tree needs five days notice. Where a tree is an immediate risk of serious harm, written notice is needed as soon as practicable after the work becomes necessary. All of this matters for extensions, scaffolding and access routes close to a tree.

What stays the same

• Building regulations approval is still needed. Permitted development and planning permission do not replace it.
• The Party Wall etc. Act 1996 still applies to work on or near a shared wall.
• A Lawful Development Certificate from the council confirms that a proposal is permitted development and needs no planning application.
• Flats have no householder permitted development rights, inside or outside a conservation area.
• If the house is also listed, listed building consent is a separate requirement. See our listed building restoration page.

What to check for your house

• Whether the property is a house or a flat.
• Whether the building is listed.
• Whether the street is in a conservation area, whether an Article 4 direction applies there, and which rights it removes.
• Whether an earlier planning permission for the house has a condition that removed permitted development rights.
• Whether any tree near the work has a Tree Preservation Order.
• The exact proposal: the type of work, its size and where it sits on the house.

How we handle a project in a conservation area

Before design starts we check the street against the council's conservation area map, any Article 4 direction and the conservation area appraisal. We then prepare the drawings and submit the planning application or Lawful Development Certificate as part of project management. For loft and extension options on period houses, see the loft conversion and house extension pages.

Frequently asked questions

Do I need planning permission for a dormer in a conservation area?

Yes. Roof extensions, including rear dormers, mansards and hip-to-gable conversions, are not permitted development in a conservation area, so they need a planning application. Rooflights that project no more than 0.15 metres beyond the slope of the original roof can still be permitted development, with the same conditions for windows on a side roof slope as elsewhere.

Can I build a rear extension in a conservation area without planning permission?

A single-storey rear extension of up to 3 metres (4 metres for a detached house) can be permitted development, within the usual height, boundary and garden coverage limits. The prior approval route for larger extensions of up to 6 or 8 metres is not available in a conservation area, and any rear extension of more than one storey needs planning permission. An Article 4 direction or a condition on an earlier permission can remove these rights.

Can I cut down a tree in my garden in a conservation area?

First check whether the tree has a Tree Preservation Order. If it does, you need the council's consent under the Order before any work, unless a statutory exception applies, and a notice is not enough. If it does not, you must give the council six weeks notice (a section 211 notice) before cutting down, topping, lopping or uprooting it, unless an exception applies, such as a trunk no more than 75 millimetres in diameter measured 1.5 metres above the ground. If the council does not make an Order within the six weeks, the work may be done within two years of the notice.

How do I find out whether my house is in a conservation area or under an Article 4 direction?

Check the conservation area map on your council website or the national planning data map, and read the conservation area appraisal for your street. Councils list the conservation areas that have Article 4 directions, for example Waltham Forest lists Leytonstone and Walthamstow Village.

Do flats in a conservation area have permitted development rights?

No. Householder permitted development rights apply to houses, not to flats, anywhere in England. External changes to a flat usually need planning permission.

Sources

• Permitted development rights for householders: technical guidance, Ministry of Housing, Communities and Local Government
• The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1
• Tree Preservation Orders and trees in conservation areas, GOV.UK
• Conservation areas and listed buildings, Waltham Forest Council
• Brockley conservation area, Lewisham Council

This guide summarises the national rules for houses in England. It is general information, not a planning decision: the council decides each case, so confirm your proposal with the council or apply for a Lawful Development Certificate.