Basement Conversion Drawings in Croydon

Which Croydon postcodes does this basement conversion service cover?

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

How does a basement conversion differ street by street across Croydon?

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

• South Norwood (SE25) — basement conversion 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) — Edwardian terraces defines Thornton Heath, where edwardian terraces set what a basement conversion can do. Edwardian houses rarely have a usable cellar across CR7. Any Thornton Heath basement conversion is validated by Croydon Council, with Thornton Heath station the usual Thornton Heath reference point on the site plan.
• Purley (CR8) — a basement conversion 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 conversions against its own Purley character guidance, and the location plan we draw for Purley references Purley Way.
• Coulsdon (CR5) — 1930s semi-detached, Edwardian villas defines Coulsdon, where 1930s semi-detached set what a basement conversion can do. 1930s houses were built without cellars across CR5. Any Coulsdon basement conversion is validated by Croydon Council, with Coulsdon South the usual Coulsdon reference point on the site plan.
• Addiscombe (CR0) — basement conversion work in Addiscombe means edwardian terraces. Addiscombe is Edwardian terraces. Edwardian houses rarely have a usable cellar throughout CR0. Croydon Council decides the Addiscombe application, and Addiscombe Road anchors the Addiscombe location plan.
• Shirley (CR0) — 1930s semi-detached defines Shirley, where 1930s semi-detached set what a basement conversion can do. 1930s houses were built without cellars across CR0. Any Shirley basement conversion is validated by Croydon Council, with Shirley Park the usual Shirley reference point on the site plan.
• Selhurst (SE25) — a basement conversion 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 conversions against its own Selhurst character guidance, and the location plan we draw for Selhurst references Selhurst Park.

Does Croydon planning policy restrict a basement conversion?

How designation changes a Croydon basement conversion: Croydon Council maintains 24 conservation areas, including Purley, Shirley Park, South Norwood. Inside any of them a Croydon basement conversion cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Shirley Park sets the tone for Croydon casework.

Croydon permitted development status: there is no borough-wide direction from Croydon Council, so a basement conversion at a SE19 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a Croydon sale to argue it later.

Croydon housing stock: 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. Read that before choosing a basement conversion route in Croydon — construction, not postcode, sets what is achievable. Croydon Council charges £548 for a householder application and has 8 weeks to determine it.

What happens if a Croydon property sits on a boundary?

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

Sources for this Croydon basement conversion 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.