House Extensions Orpington

GS Renovation plans and builds house extensions across Orpington, where interwar and post-war semis, detached houses and bungalows sit on the generous plots that make Bromley's suburbs so well suited to extending. Our founder's 30+ years on the tools show in the parts nobody sees: foundations to the engineer's depth, the drainage run under the new floor and the steel over the opening.

In Orpington, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Orpington: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Kitchen extensions and ground-floor extensions in Orpington

The commonest Orpington request is a single-storey ground-floor extension across the back of the house, usually a kitchen extension that turns a small 1930s or post-war kitchen into a kitchen-diner opening onto the garden. The wide plots also suit double storey rear extensions, side extensions over the drive and wrap-around designs. We start with proper foundations and groundworks sized to the ground conditions, then form the new openings with steel beams calculated by the engineer we appoint and signed off by building control. The result blends into the original house rather than looking bolted on to the back.

Extending across the side of a detached or semi-detached Orpington home often means widening the kitchen or creating a new family room. We match brickwork and rooflines to the existing house and the street, install the roof works, and carry out a complete fit-out including plastering, electrics, plumbing and decoration, so you move straight into a finished space rather than a shell that needs another trade to complete.

Housing in Orpington

Orpington has about 10,530 homes on the Council Tax list: 6% pre-1919, 39% interwar and 55% post-war, with flats making up 17% and houses 83%. A rear extension on a semi in Orpington digs beside the attached neighbour, so one party wall notice is usual, and 33% of homes here are semi-detached.

Side and wraparound extensions on Orpington semis under Bromley policy

Where an Orpington semi or detached house has a side garden, and 51% of homes here are one or the other, Bromley's Local Plan decides the shape of a side extension before any drawing starts. Policy 8 normally requires a proposal of two or more storeys to keep a minimum 1 metre space from the side boundary for its full height and length. A two storey side extension built up to the fence is therefore normally ruled out. The Local Plan also says flat-roofed side extensions of two or more storeys to dwellings of traditional roof design will normally be resisted. On a hipped 1930s semi, that points to a pitched roof over the upper storey.

Neither rule applies to a single storey side extension, so one practical answer is a ground floor wraparound across the side and rear, with any upper storey set in from the boundary or left out. For building control, Bromley adds together the floor areas of extensions built at the same time, measured internally, so the side piece and the rear piece count as one. Its schedule has a line for a domestic extension of over 10 and up to 40 square metres with no basement, and a wraparound on a semi can pass the top of that band once both parts are added.

Planning and party walls for Bromley homes

A modest single storey rear extension on a BR6 semi can often use permitted development; double storey or side extensions usually need a full application to Bromley Council. The deciding tests are size, height, distance to the boundary, whether the house is in a conservation area and whether its permitted development rights have been removed. Near a limit, a lawful development certificate from Bromley Council settles it before the foundations are dug.

On the semi-detached homes so common in BR6, extending near or against the boundary brings the Party Wall Act into play, and you serve notice on the neighbours as building owner before work begins, or your surveyor does. Foundations dug close to a shared boundary can also trigger the Act. We give you the drawings and programme the notices need and plan the start around them, alongside the building regulations approvals, keeping both the council and your neighbours informed so the project runs smoothly.

Side return extensions in Orpington

Side returns belong to Victorian and Edwardian terraces, and only 6% of homes in Orpington predate 1919, so they are the exception here; most extensions run across the full rear width instead. Our side return extension page covers the build in detail, with build rates of £2,400 to £3,200 per m².

Double storey extensions in Orpington

Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Orpington often needs planning permission from Bromley Council. With 51% of homes here semi-detached or detached, the side of the house is often an option too. The Orpington Town Centre SPD states that the Orpington Priory conservation area covers the northern part of the town centre and the Broomhill conservation area lies to its west (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• Full fit-out, finishing and making good
• Levels, drainage and landscaping made good around the new build
• Flat and pitched roofs with rooflights or lanterns

VOA Council Tax stock of properties, March 2025, for Orpington West, Orpington East and Orpington South. Counts rounded by the VOA.

Before committing to house extensions in Orpington, it is worth looking at RSJ and steel beam installation in Orpington, house extensions across Bromley, wraparound extensions, a garage conversion instead, our London house extensions page and Double Storey Extension Cost.

Trusted House Extensions in Orpington

GS Renovation is a strong choice for Orpington extensions because one accountable team covers structure, building control and finish, and works with your designer on planning. We know how Bromley Council handles applications and when permitted development applies, and we tell you when a party wall notice to a neighbouring semi is needed and give you the drawings for it. Backed by our founder's 30+ years on the tools, we deliver watertight, well-built extensions that respect the character of the street.

• One point of contact on the phone, not a call centre
• Building control inspected at foundation, damp course and steel stages
• Programme planned around party wall notice periods before excavation near a neighbour

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.