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House extensions in South London

Rear, side return, wrap-around and double-storey extensions. We take on a select number each year, and we manage them from the first drawing to building control sign-off.

Discuss your extension

Proposed elevation, Lynwood Grove, Orpington

Four ways to extend, and what each one adds

Plan, from above

garden street kitchen existing house side passage

Section, from the side

existing house extension

Planning
Good for

From an idea to building control sign-off

You don't need drawings before you call us. Get in touch at any stage. If you haven't appointed an architect or structural engineer, we can recommend them.

  1. 1

    Site visit

    We look at the house and the garden and talk through what's possible and roughly what it costs.

  2. 2

    Drawings

    Your architect draws it up. We coordinate with your design team throughout.

  3. 3

    Planning

    Which route depends on the size, the property and where it is.

    Permitted Development: no full application for many single-storey rear extensionsFull planning permission: larger schemes, conservation areas, listed buildings, flats
  4. 4

    Building Regulations

    Needed either way. We coordinate the structural engineer and manage the process.

  5. 5

    The build

    One fixed price, one point of contact, start and finish dates in writing.

  6. 6

    Sign-off and handover

    Final walkthrough, building control sign-off, all documents and guarantees handed over.

One extension, start to finish

A first-floor rear extension and new roof on a century-old house in Orpington.

Scaffold and site protection go up front and rear, Lynwood Grove, Orpington — Fellner Construction
1Scaffold and site protection go up front and rear
Roof and chimney taken down in a controlled sequence, Lynwood Grove, Orpington — Fellner Construction
2Roof and chimney taken down in a controlled sequence
Steel beams installed to the structural engineer's drawings, Lynwood Grove, Orpington — Fellner Construction
3Steel beams installed to the structural engineer's drawings
Extension walls built in blockwork, Lynwood Grove, Orpington — Fellner Construction
4Extension walls built in blockwork
New roof structure over house and extension, Lynwood Grove, Orpington — Fellner Construction
5New roof structure over house and extension
Roof covering with flush-fitted solar panels, Lynwood Grove, Orpington — Fellner Construction
6Roof covering with flush-fitted solar panels
External wall insulation and roof windows, Lynwood Grove, Orpington — Fellner Construction
7External wall insulation and roof windows
Finished: rendered, glazed and handed over, Lynwood Grove, Orpington — Fellner Construction
8Finished: rendered, glazed and handed over
Read the full Lynwood Grove case study
  • Fixed price in writingAny change is agreed in writing first.
  • Deposit capped at 20%Then staged payments against milestones.
  • 10-year structural guaranteeOn structural alterations, plus 12 months on workmanship.
  • £3m public liabilityInsured for residential works.
  • You deal with the ownerOne point of contact, first visit to handover.

What would you do with another room?

Tell us about your house and what you want from the space. We reply within one working day and arrange a no-obligation site visit.

Get a fixed-price quote Or call +44 7834 390 350, Monday to Friday, 8am to 6pm