Self-Build and New Build on a Plot in London: What You Need to Know

Available plots for residential new build in London are scarce, expensive, and intensely competitive. Types of plot opportunity:

• **Garden plot (back-land development):**
• The most common route in inner London — an existing large garden is subdivided to create a new building plot behind the existing house. To be viable, the plot must:
• •Have independent access to the highway (or acquire access through the existing property, which is complex)
• •Have sufficient daylight access to meet Building Regulations and planning policy requirements
• •Not be subject to covenants preventing new development
• •Have sufficient separation from the existing and neighbouring properties to avoid unacceptable overlooking or overshadowing

**Side or rear infill:** Small plots between existing buildings — often L-shaped or awkwardly configured — created where a gap exists in the urban grain. These often require very close engagement with planning at the design stage.

**Garage/outbuilding demolition:** A detached garage or outbuilding on a large plot can sometimes be demolished and replaced with a small dwelling. This typically requires planning permission even where the garage itself was previously permitted.

**Self-Build Register:** London boroughs are required to maintain a self-build register. Registering does not guarantee a plot, but demonstrates demand and may influence borough planning policy. Some boroughs also have specific self-build allocations within larger development sites.

• **Plot assessment:**
• Before committing to a plot purchase, commission or carry out:
• •A structural/ground conditions assessment — particularly relevant in areas with historic industrial use, fill, or London clay movement risk
• •A pre-application planning enquiry to assess the borough's view on new build development of the plot
• •Legal title investigation — covenants, rights of way, wayleaves, and neighbouring rights can all significantly affect development potential
• •A drainage and utilities assessment — cost and feasibility of connecting new services
• •A daylight/sunlight assessment for shadow impact on neighbours (required for planning in sensitive locations)

Planning permission is required for all new dwellings in London — there is no permitted development route for constructing a new home. London's planning policy environment is complex and varies considerably between boroughs.

**Key planning policy considerations:**

**Character and design:** New buildings in London are assessed against local character, the established building line, height, scale, massing, and architectural quality. London Planning Policy (NPPF, London Plan, and borough Local Plan) strongly favours contextual design that respects the existing urban grain — but this does not mean pastiche. Contemporary design that responds to context (height, setback, scale, rhythm of openings) is increasingly supported across London boroughs.

**Density:** London's planning policy uses density matrices (habitable rooms per hectare) to guide appropriate density. A new single dwelling on a back-land plot in a low-density suburban area may be assessed against a very different density policy than the same plot in an inner London high-density area. Higher density is generally encouraged by the London Plan, particularly in Opportunity Areas and around transport nodes.

**Overshadowing and daylight:** The BRE guidelines on daylight and sunlight to existing buildings are routinely applied in London. New build development on constrained plots frequently encounters objections and refusals on daylight impact grounds — particularly where neighbours have gardens and rear-facing habitable rooms that would be overshadowed.

**Garden land development:** Most London boroughs have policies that restrict inappropriate development of residential garden land — the 'garden grabbing' policies. These vary in their stringency between boroughs. Pre-application advice is essential before assuming a garden plot is developable.

• **Application documentation:**
• New build planning applications in London typically require:
• •Design and Access Statement
• •Daylight and Sunlight Assessment (for plots adjacent to existing properties)
• •Arboricultural Assessment (if existing trees are present)
• •Transport Statement (where access or parking is affected)
• •Flood Risk Assessment (where in a flood zone)
• •Heritage Impact Assessment (where near a listed building or Conservation Area)

• **Build cost:**
• New build construction in London (excluding land, professional fees, and planning costs) typically costs:
• •Traditional masonry construction (brick and block): £2,500–£4,000/m² in London (2026 market)
• •Timber frame: £2,200–£3,500/m² in London (faster programme, more factory-controlled quality)
• •Modern Methods of Construction (MMC — volumetric modular, panelised systems): potentially £2,000–£3,200/m² but with significant lead times and plant access requirements

For a 100m² 3-bed dwelling in London, build cost alone: £250,000–£400,000.

• **Total cost including land and fees:**
• For a new single dwelling in inner London:
• •Land/plot cost: highly variable — from £100,000 (edge of outer London) to £500,000+ (inner London)
• •Professional fees (architect, structural engineer, planning consultant, building control): typically 10–15% of build cost
• •Planning application and condition discharge fees, CIL (Community Infrastructure Levy where applicable), Section 106 contributions
• •Financing costs
• •VAT: new build dwellings are zero-rated for VAT on the construction works (significant cost advantage over renovation — which is standard-rated)

**Construction approach:** Most new build plots in London use traditional masonry (brick and blockwork cavity wall with timber frame roof) or timber frame construction. The constrained access typical of London plots (narrow side passages, no crane access, no large vehicle access) means modular volumetric construction is rarely suitable for the typical infill or back-land London plot.

**Programme:** A single new dwelling in London (planning already in place): 14–24 months from start on site to practical completion, depending on size and complexity.