House Extension Drawings in City of London

Most standard extensions in City of London fall under Permitted Development — single-storey rear up to 3m (attached) or 4m (detached), side returns up to half the width of the house. However, City of London has Article 4 Directions that may remove these rights in specific streets, and flats, listed buildings and conservation areas always need full planning. We check PD eligibility before quoting.

Standard permitted development allows single-storey rear extensions up to 3m (attached house) or 4m (detached) in City of London. Larger extensions up to 6m/8m are allowed under Prior Approval (Class AA). Flats, listed buildings and Article 4 areas in City of London are excluded from these PD rights.

Our fixed-fee architectural package starts at £1,225 for a City of London extension (planning + building regs + structural). Typical City of London build costs are £2,400–£3,500 per square metre including VAT — so a 25m² side return extension is £60,000–£87,500 to construct.

City of London does not have a borough-specific basement policy beyond the national framework — basement conversions are generally permissible subject to structural, drainage and flood-risk considerations. Thames Water Build Over Agreements apply where you're within 3m of a public sewer.

Most Victorian terraces in City of London (particularly in Barbican) benefit from both — a side return extension infills the narrow side passage to create a wider kitchen, a rear extension projects back into the garden. A wraparound combines the two. We recommend the best option at the free site visit.

City of London's very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats terraced and semi-detached stock typically suits rear single-storey extensions (kitchen-diners), side-return infill extensions, or double-storey rear. Wraparound extensions combine both directions for maximum gain. We recommend the most viable option at the free site visit.

We cover all City of London postcodes — {postcodes} — with local surveyors. Survey appointments within 3 working days. Fixed fees — no hourly billing.

City of London Corporation follows the London Plan and its own Local Development Framework. Extensions must match or complement existing materials, respect neighbour amenity and comply with Part L. We include a Pre-Application Advice summary where the planning history is complex.