London has more than 1,000 conservation areas, from the Georgian squares of Bloomsbury to Victorian suburbs in every borough. Designation does not prevent extension or renovation. It changes what needs permission, and it raises the standard against which the design is judged.
What designation means
A conservation area is designated by the council for its special architectural or historic interest, and the council has a duty to preserve or enhance that character. Changes visible from the street are assessed against it. Most councils publish a conservation area appraisal setting out what matters in each area: materials, rooflines, front gardens, window patterns.
We read the appraisal before drawing anything, and test the scheme against the heritage officer's likely concerns before it is developed in detail. The appraisal is, in effect, the officer's brief.
Permitted development is narrower
Houses in conservation areas keep some permitted development rights, but fewer than elsewhere:
- Side extensions need planning permission.
- Rear extensions of more than one storey need planning permission.
- Cladding the exterior in stone, timber, render or tiles needs permission.
- Roof extensions, including rear dormers, are not permitted development, so a dormer loft conversion needs planning permission.
Many London conservation areas also carry Article 4 directions that remove further rights, often covering front windows, doors, boundary walls and the paving of front gardens. Councils publish them on their websites.
What makes an application succeed
- Materials. Brick, slate or clay tiles and timber windows that match the existing house are usually expected wherever the work is visible.
- A quiet street elevation. Councils are generally more flexible at the rear, where change is less visible from public view. We concentrate the ambition there.
- Evidence of understanding. A heritage or design statement that engages with the appraisal shows the officer the scheme has been designed in response to it, not adjusted afterwards.
- Neighbours. Objections carry weight in close-knit streets. Explaining the scheme early often avoids them.
- Pre-application advice. For larger or sensitive schemes, the council's pre-application service gives an early view before committing to full drawings. We use it selectively, where the officer's view is genuinely uncertain.
Trees
Trees in a conservation area are protected even without a Tree Preservation Order. Six weeks' notice must be given to the council before felling or pruning most trees with a trunk diameter over 75mm, measured 1.5 metres above ground. This matters early if an extension or basement is planned near one.
Our approach
We design extensions, loft conversions and alterations in conservation areas across London, and prepare the heritage and design statements councils ask for. See our planning applications service, or send us the address and we will check what applies to the property.