House Extension South East London Across Twenty Districts and Five Councils
South east London holds the widest range of housing anywhere in the capital. Georgian townhouses on the Greenwich waterfront. Estate cottages built to a livery company’s rules in 1871. Arts and crafts terraces in Walworth. A 1915 estate in Eltham put up in ten months. Docklands houses from the 1980s in Rotherhithe, where almost nothing is Victorian at all. Analysis of the 2021 census identified the region as one of the two fastest changing parts of London, with the change coming through turnover in that historic stock rather than new building.
Which means a great many people here have bought a period house and want to make more of it. The work is usually straightforward enough in construction terms: a Victorian terrace is built the same way in Dulwich as it is anywhere else in London, and the brickwork does not care which side of a boundary it sits on.
The planning does. Five councils cover this region under the London Plan — Bexley, Bromley, Greenwich, Lewisham and Southwark — and the SE postcodes stretch further, into Lambeth at Kennington and Herne Hill and as far as Croydon at South Norwood. Each maintains its own conservation areas, its own Article 4 directions, its own validation checklist and its own design guidance, and the differences between them are not small. Design And Build works across the whole region, with the architects, engineers, surveyors and trades all employed by us rather than found for each job.
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Five regimes, one region: builders Southeast London
Southwark counts 480, Lambeth counts four
Put the two boroughs side by side and the difference is hard to credit. Southwark, which takes in Peckham, has made around four hundred and eighty Article 4 directions, described as one of the most extensive networks in London, across fifty-three conservation areas.
Lambeth has four, across around sixty conservation areas. The catch is that raw numbers mislead in both directions. Almost all of Southwark’s target Class MA, the commercial to residential route, rather than householder work, and only a couple are site-specific to homes. Three of Lambeth’s four are also commercial, and the last of them applies only to shared housing in one part of Streatham. Counting directions tells you nothing; reading what each one removes tells you everything.
Bromley protects a view of Croydon
Bromley holds sixty-nine conservation areas, the second highest of any London borough. In February 2022 it confirmed a series of directions, effective that March, removing permitted development for upward extensions and additional storeys across named areas.
Three of them are unlike anything else in London, because their subject is a sightline rather than a place. From Village Way in Beckenham, two of them guard what you can see — Croydon town centre in one case, a church in the other. The third takes in the eastern skyline above the Ravensbourne Valley. If your house sits inside one, an officer will ask what your roof does to a view somebody has from somewhere else entirely.
Lewisham operates two regimes side by side
Lewisham records, which stretches from Deptford down through Lee to Beckenham Place Park, around eighty-nine Article 4 parcels, and for a homeowner they split into two groups that behave quite differently.
Conservation area directions remove householder permitted development, and their scope varies enormously: Forest Hill has one across all forty-five hectares of its designation, Sydenham Thorpes has one across a whole area that steps aside for flats, and St Mary’s in Lewisham has one whose streets the council asks you to telephone about. On top of that sits a blanket rule against turning a house into a small shared home: it reached the southern wards around Catford in March 2020 and the remainder of the borough in January 2024.
Georgian townhouses to 1980s dockside: house renovation Southeast
Turnover in the historic housing stock
The phrase comes from an analysis of the 2021 census, which identified new corridors of relative affluence forming across south east London and traced the change to turnover in the historic housing stock alongside new build.
In practice that means period houses changing hands and being worked on. It is visible in the application records: whole-house renovations in Victorian and Edwardian terraces, kitchens moved to the back, services replaced wholesale, and a great deal of work reversing what the 1970s and 1980s did to these buildings. Bring interior design in early enough that the plan is not already fixed.
Flats going back to houses in SE4
The most striking pattern in the region runs backwards. In Brockley and neighbouring New Cross, two applications in roughly a year sought to convert flats into single houses, one of them reversing a five-way split, and no application went the other way in that postcode at all.
The Planning Portal calls it deconversion, distinguishing it from amalgamation, and notes that deconversion is generally viewed more favourably. Nothing about it is small. Each former flat brought its own kitchen, its own bathroom stack and its own consumer unit; the stair has to run the full height again, and fire separation comes out at every level. It also has to be planned alongside the finance, because a building registered as flats is awkward to lend against mid-conversion.
Heat pumps meeting listed buildings
The newest planning problem in the region is retrofit against heritage, and it is showing up in the notices.
At Lammas Green in Sydenham, a Grade II listed property went to the council after the event, seeking both consents at once to cover a heat pump, new glazing and a garden building. A Lewisham application put solar panels on alongside an addition at the back. On a listed building each of those is an alteration needing consent before installation rather than after, and the council can require removal. Applying first is always cheaper.
Each borough validates differently, and design and build south east London handles it
Where one road is split between two boroughs
Herne Hill is the clearest example. Lambeth’s conservation area covers the west side of one road; Southwark’s Stradella conservation area covers the east side of the same road. Two councils, two local plans, two portals.
It is not unusual here. Beckenham Place Park is a BR3 address determined by Lewisham rather than Bromley, and Lewisham’s own appraisal calls that boundary somewhat arbitrary. Sydenham spans three boroughs. Upper Norwood spans four, with three conservation areas from three different councils meeting at a single junction. The postcode does not settle it and neither does the ward.
Greenwich asks permission to paint
Greenwich holds twenty-three conservation areas, of which six carry Article 4 directions, and one of those is worth knowing about even if you live nowhere near it.
In the Ashburnham Triangle in Greenwich, the direction removes the right to paint the exterior of your own house. Its schedule names individual house numbers, with specific exclusions. That is a level of control most homeowners would not imagine existed, and it is the reason a general statement about permitted development is worth very little without the address attached.
Roofs decide it in some postcodes
Where a scheme succeeds or fails varies by district in ways that are only visible in the record. In some postcodes the argument is always the roof.
Herne Hill produced four roof cases in one borough list: one refused, two settled at appeal, one submitted retrospectively. In East Dulwich the applications specify ridge raises of two hundred, two hundred and seventy-five, three hundred and four hundred millimetres, because the Victorian roofs clear the required head height only just. Elsewhere the local move is a hip to gable, or an outrigger, or a mansard rather than a dormer. Knowing which is which comes from reading the district, not the region.
Already familiar with your council: a construction company south east London
Ground that behaves differently every few miles
The geology changes as much as the planning. Rotherhithe sits on filled docks, where surveyors report structural movement in riverside apartments on former dock ground. Charlton, Deptford and Abbey Wood carry made ground of their own.
South of the river valley, from Blackheath onwards, the problem inverts into clay. A Gipsy Hill application sought to remove a poplar specifically to stop its influence on the soil below foundation level. Beckenham and Brockley sit on shrink-swell clay where mature trees and shallow Victorian footings produce the diagonal cracking owners photograph. Our structural engineers design foundations against what a specific site is doing rather than from a standard detail.
Twenty districts, one payroll
The argument for a firm that works across the whole region, from Woolwich to the Surrey edge, rather than one corner of it is not that we have seen more houses. It is that we have submitted to all of these councils and know what each of them asks for.
The survey, the drawings, the heritage statements, the engineering and the construction sit inside one construction company. On a terrace both shared walls come into play under the Party Wall etc. Act 1996, and our own surveyors take that on. Where a scheme turns out to need no permission at all, a lawful development certificate records the position properly rather than leaving it to be argued at sale.
Area We Cover
Give us the postcode and the borough follows
One address does most of the work. It settles which of five councils decides, which conservation area reaches you, whether an Article 4 direction applies and what it removes, and what your permitted development position actually is.
Send it and you get the answer in writing, alongside a read of what has recently been permitted a few doors away. We work across Greenwich, Deptford, Brockley, Lewisham, Forest Hill, Sydenham, Rotherhithe, East Dulwich, Herne Hill, Beckenham and the districts around them, from the river down to the Kent and Surrey edges.
Surveys cost nothing. The first thing we establish is which council you are persuading.
