Rear Dormer Loft Conversion Drawings in Anerley (SE20)

Which SE20 postcodes does this rear dormer service cover?

Every SE20 postcode district we draw in, the stock that dominates it and the authority that validates a rear dormer there. SE20 fees below are the statutory England rates for 2026, not rear dormer estimates.

What changes about a rear dormer in each part of SE20?

Roof pitch, wall build-up and plot depth change every few SE20 streets, and each one changes what a rear dormer can achieve at that address.

• Inside SE20: Penge (SE20) — Victorian and Edwardian terraces defines Penge, where victorian and edwardian terraces set what a rear dormer can do. Full-width rear dormers on Victorian terraces here are the default across SE20. Any Penge rear dormer is validated by Bromley Council, with Penge East station the usual Penge reference point on the site plan.
• Bordering SE20: Bromley (BR1, BR2) — Victorian and Edwardian centre defines Bromley, where victorian terraces, edwardian villas, post-war flats set what a rear dormer can do. Full-width rear dormers on Victorian terraces here are the default across BR1. Any Bromley rear dormer is validated by Bromley Council, with Bromley High Street the usual Bromley reference point on the site plan.
• Bordering SE20: Beckenham (BR3) — a rear dormer in Beckenham starts from edwardian villas, 1930s semi-detached, and Beckenham reads as Edwardian villas, 1930s semi-detached. The deeper Edwardian rear slope takes a full-width dormer without breaching the 40 m³ or 50 m³ volume limits on most of these houses in BR3. Bromley Council assesses Beckenham rear dormers against its own Beckenham character guidance, and the location plan we draw for Beckenham references Beckenham Junction.
• Bordering SE20: Chislehurst (BR7) — a rear dormer in Chislehurst starts from 1930s detached, edwardian villas, and Chislehurst reads as Large 1930s detached, conservation. The deeper Edwardian rear slope takes a full-width dormer without breaching the 40 m³ or 50 m³ volume limits on most of these houses in BR7. Bromley Council assesses Chislehurst rear dormers against its own Chislehurst character guidance, and the location plan we draw for Chislehurst references Chislehurst Caves.
• Bordering SE20: Bickley (BR1) — 1930s detached, conservation defines Bickley, where 1930s detached, edwardian villas set what a rear dormer can do. The deeper Edwardian rear slope takes a full-width dormer without breaching the 40 m³ or 50 m³ volume limits on most of these houses across BR1. Any Bickley rear dormer is validated by Bromley Council, with Bickley station the usual Bickley reference point on the site plan.
• Bordering SE20: Orpington (BR5, BR6) — a rear dormer in Orpington starts from 1930s semi-detached, and Orpington reads as 1930s semi-detached, post-war. Hip-to-gable plus rear dormer is the standard sequence on these 1930s semis in BR5. Bromley Council assesses Orpington rear dormers against its own Orpington character guidance, and the location plan we draw for Orpington references Orpington High Street.
• Bordering SE20: Petts Wood (BR5) — rear dormer work in Petts Wood means 1930s semi-detached. Petts Wood is 1930s semi-detached, garden suburb. Hip-to-gable plus rear dormer is the standard sequence on these 1930s semis throughout BR5. Bromley Council decides the Petts Wood application, and Petts Wood station anchors the Petts Wood location plan.
• Bordering SE20: West Wickham (BR4) — a rear dormer in West Wickham starts from 1930s semi-detached, and West Wickham reads as 1930s semi-detached. Hip-to-gable plus rear dormer is the standard sequence on these 1930s semis in BR4. Bromley Council assesses West Wickham rear dormers against its own West Wickham character guidance, and the location plan we draw for West Wickham references West Wickham station.
• Bordering SE20: Biggin Hill (TN16) — 1930s semi-detached, rural fringe defines Biggin Hill, where 1930s semi-detached set what a rear dormer can do. Hip-to-gable plus rear dormer is the standard sequence on these 1930s semis across TN16. Any Biggin Hill rear dormer is validated by Bromley Council, with Biggin Hill Airport the usual Biggin Hill reference point on the site plan.
• Bordering SE20: Keston (BR2) — Edwardian and 1930s village defines Keston, where edwardian villas, 1930s semi-detached set what a rear dormer can do. The deeper Edwardian rear slope takes a full-width dormer without breaching the 40 m³ or 50 m³ volume limits on most of these houses across BR2. Any Keston rear dormer is validated by Bromley Council, with Keston Ponds the usual Keston reference point on the site plan.

Does SE20 planning policy restrict a rear dormer?

Conservation areas covering SE20 (Anerley / Penge): Bromley Council runs 48, and Chislehurst, Beckenham, Keston are the ones SE20 (Anerley / Penge) owners meet most. A rear dormer inside a SE20 (Anerley / Penge) conservation area loses permitted development, so the SE20 (Anerley / Penge) submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Bickley a rear dormer is judged on the street elevation first.

Article 4 and your SE20 (Anerley / Penge) rear dormer: Bromley Council has made no borough-wide direction, so permitted development for a rear dormer in SE20 (Anerley / Penge) generally survives outside SE20 (Anerley / Penge) conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SE20 owner records that a rear dormer was lawful.

What SE20 (Anerley / Penge) is built from: Large 1930s detached and semi-detached in Chislehurst and Bickley; Edwardian in Beckenham; Victorian in Bromley town; Metropolitan Green Belt covers significant rural-fringe land. Largest London borough by area; substantial Green Belt; conservation areas in most town centres; generally permissive elsewhere. That mix decides the rear dormer route in SE20 (Anerley / Penge) more than the postcode does, and it is what a Bromley Council case officer reads first. A householder application costs £548 paid to Bromley Council direct, with 8 weeks to a decision once validated.

Conservation areas covering SE20 (Anerley / Penge): Croydon Council runs 24, and Crystal Palace, Old Coulsdon, Purley are the ones SE20 (Anerley / Penge) owners meet most. A rear dormer inside a SE20 (Anerley / Penge) conservation area loses permitted development, so the SE20 (Anerley / Penge) submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Shirley Park a rear dormer is judged on the street elevation first.

Article 4 and your SE20 (Anerley / Penge) rear dormer: Croydon Council has made no borough-wide direction, so permitted development for a rear dormer in SE20 (Anerley / Penge) generally survives outside SE20 (Anerley / Penge) conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SE20 owner records that a rear dormer was lawful.

What SE20 (Anerley / Penge) is built from: 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. That mix decides the rear dormer route in SE20 (Anerley / Penge) more than the postcode does, and it is what a Croydon Council case officer reads first. A householder application costs £548 paid to Croydon Council direct, with 8 weeks to a decision once validated.

What happens if a SE20 property sits on a boundary?

• Bexley — adjoining SE20 (Anerley / Penge), with 16 conservation areas centred on DA1. A rear dormer on the far side of the SE20 (Anerley / Penge) line is determined by Bexley Council, so the SE20 (Anerley / Penge) quote for rear dormers is checked against Bexley guidance before it is issued.
• Croydon — cross the SE20 (Anerley / Penge) boundary and Croydon Council takes the rear dormer instead, applying 24 conservation areas of its own around CR0. We re-price rear dormers at the SE20 (Anerley / Penge) edge because Croydon policy and Bromley policy rarely align on rear dormer depth.
• Southwark — the Southwark boundary runs against Bromley, so a rear dormer a street from SE20 (Anerley / Penge) is decided by Southwark Council instead. Southwark runs 43 conservation areas across SE1 and its neighbours, which is why rear dormers priced for SE20 (Anerley / Penge) are re-checked against Southwark policy whenever the SE20 (Anerley / Penge) address sits on that edge.
• Lewisham — cross the SE20 (Anerley / Penge) boundary and Lewisham Council takes the rear dormer instead, applying 30 conservation areas of its own around SE3. We re-price rear dormers at the SE20 (Anerley / Penge) edge because Lewisham policy and Bromley policy rarely align on rear dormer depth.
• Sutton — adjoining SE20 (Anerley / Penge), with 17 conservation areas centred on SM1. A rear dormer on the far side of the SE20 (Anerley / Penge) line is determined by Sutton Council, so the SE20 (Anerley / Penge) quote for rear dormers is checked against Sutton guidance before it is issued.
• Merton — cross the SE20 (Anerley / Penge) boundary and Merton Council takes the rear dormer instead, applying 28 conservation areas of its own around SW16. We re-price rear dormers at the SE20 (Anerley / Penge) edge because Merton policy and Croydon policy rarely align on rear dormer depth.
• Lambeth — adjoining SE20 (Anerley / Penge), with 64 conservation areas centred on SE1. A rear dormer on the far side of the SE20 (Anerley / Penge) line is determined by Lambeth Council, so the SE20 (Anerley / Penge) quote for rear dormers is checked against Lambeth guidance before it is issued.
• Bromley — cross the SE20 (Anerley / Penge) boundary and Bromley Council takes the rear dormer instead, applying 48 conservation areas of its own around BR1. We re-price rear dormers at the SE20 (Anerley / Penge) edge because Bromley policy and Croydon policy rarely align on rear dormer depth.

Sources for this SE20 rear dormer 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.