The Upper Norwood villas of Croydon suit a basement dig

Which postcode districts around Croydon do we cover for basement extension work?

Every Croydon postcode district we draw in, the stock that dominates it and the authority that validates a basement extension there. Croydon fees below are the statutory England rates for 2026, not basement extension estimates.

Which Croydon neighbourhoods suit a basement extension best?

Roof pitch, wall build-up and plot depth change every few Croydon streets, and each one changes what a basement extension can achieve at that address.

• Selhurst (SE25) — a basement extension in Selhurst starts from edwardian terraces, and Selhurst reads as Edwardian terraces. Edwardian houses rarely have a usable cellar in SE25. Croydon Council assesses Selhurst basement extensions against its own Selhurst character guidance, and the location plan we draw for Selhurst references Selhurst Park.
• Croydon (CR0) — post-war centre, Edwardian residential ring defines Croydon, where edwardian terraces, post-war flats set what a basement extension can do. Edwardian houses rarely have a usable cellar across CR0. Any Croydon basement extension is validated by Croydon Council, with Whitgift Centre the usual Croydon reference point on the site plan.
• Crystal Palace (SE19) — basement extension work in Crystal Palace means victorian villas, edwardian terraces. Crystal Palace is Victorian villas, hill character. Victorian cellars here convert without planning permission when the footprint and external appearance are unchanged throughout SE19. Croydon Council decides the Crystal Palace application, and Crystal Palace Park anchors the Crystal Palace location plan.
• Upper Norwood (SE19) — basement extension work in Upper Norwood means victorian villas, edwardian terraces. Upper Norwood is Victorian villas. Victorian cellars here convert without planning permission when the footprint and external appearance are unchanged throughout SE19. Croydon Council decides the Upper Norwood application, and Upper Norwood Triangle anchors the Upper Norwood location plan.
• South Norwood (SE25) — basement extension work in South Norwood means victorian terraces. South Norwood is Victorian terraces. Victorian cellars here convert without planning permission when the footprint and external appearance are unchanged throughout SE25. Croydon Council decides the South Norwood application, and South Norwood Lake anchors the South Norwood location plan.
• Thornton Heath (CR7) — a basement extension in Thornton Heath starts from edwardian terraces, and Thornton Heath reads as Edwardian terraces. Edwardian houses rarely have a usable cellar in CR7. Croydon Council assesses Thornton Heath basement extensions against its own Thornton Heath character guidance, and the location plan we draw for Thornton Heath references Thornton Heath station.
• Purley (CR8) — a basement extension in Purley starts from 1930s semi-detached, edwardian villas, and Purley reads as 1930s semi-detached, Edwardian villas. Edwardian houses rarely have a usable cellar in CR8. Croydon Council assesses Purley basement extensions against its own Purley character guidance, and the location plan we draw for Purley references Purley Way.

Does Croydon planning policy restrict a basement extension?

Croydon conservation designations: there are 24 across Croydon Council, Shirley Park, South Norwood, Crystal Palace among them. Designation costs a Croydon owner the permitted-development route: a basement extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Crystal Palace is the Croydon designation that most often changes a basement extension design.

Article 4 and your Croydon basement extension: Croydon Council has made no borough-wide direction, so permitted development for a basement extension in Croydon generally survives outside Croydon conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SE19 owner records that a basement extension was lawful.

The building fabric around Croydon: Victorian villas in Upper Norwood and Crystal Palace; Edwardian terraces in Thornton Heath and Selhurst; 1930s semi-detached in Purley and Coulsdon; post-war in Croydon central. Large, mixed-density outer borough; permissive in outer areas; heritage controls in conservation pockets; major regeneration in central Croydon. A basement extension in Croydon is scoped against that stock first.

What happens if a Croydon property sits on a boundary?

• Sutton — cross the Croydon boundary and Sutton Council takes the basement extension instead, applying 17 conservation areas of its own around SM1. We re-price basement extensions at the Croydon edge because Sutton policy and Croydon policy rarely align on basement extension depth.
• Merton — cross the Croydon boundary and Merton Council takes the basement extension instead, applying 28 conservation areas of its own around SW16. We re-price basement extensions at the Croydon edge because Merton policy and Croydon policy rarely align on basement extension depth.
• Lambeth — cross the Croydon boundary and Lambeth Council takes the basement extension instead, applying 64 conservation areas of its own around SE1. We re-price basement extensions at the Croydon edge because Lambeth policy and Croydon policy rarely align on basement extension depth.
• Bromley — adjoining Croydon, with 48 conservation areas centred on BR1. A basement extension on the far side of the Croydon line is determined by Bromley Council, so the Croydon quote for basement extensions is checked against Bromley guidance before it is issued.

Sources for this Croydon basement extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.