Knowledge Base
Planning, regulations and construction, explained.
Topic 10
New builds
For homeowners building in the garden, self-builders and small developers.
26 articles
Is my site buildable?
01Can I build a house in my garden?A separate house in a garden normally needs planning permission. Its prospects depend on the quality of both homes, access, neighbouring properties and site constraints, not simply on having spare land.02Backland, infill, corner and garage sites: what makes a good small siteA workable small site has room for good homes and the access, daylight, outdoor space and services they need. Backland, infill, corner and former garage plots have different constraints, so a site assessment must go beyond its area.03Demolish and rebuild: replacing an existing houseReplacing a house is a new development proposal, not an automatic right to rebuild it larger or in a different position. Check the planning route for both demolition and the replacement, then coordinate building regulations, ecology and the tax treatment before work starts.04Small sites in London: what the London Plan supportsThe London Plan supports well-designed housing on small sites, but it does not give every small plot planning permission. A proposal must still satisfy the relevant housing-quality, access, amenity and borough requirements.05How many homes fit on my site?The number of homes that fit is the result of a design and constraints assessment, not a calculation based on site area alone. Test the building envelope, housing mix, access and living conditions together before fixing a unit count.06Access for fire engines and bin collection on backland sitesA backland scheme must show that firefighting access and refuse collection can work in practice. These are different tests: a route acceptable for residents or bins is not automatically suitable for a fire appliance, and a fire-access design does not settle the council’s collection arrangements.07Adding storeys to an existing block of flatsAdding homes above a block of flats may use a permitted development prior-approval route only where the existing building and the proposal meet all its conditions. Otherwise a planning application is needed; either route is separate from structural, fire-safety and building control requirements.
Design standards
08Minimum flat and room sizes: the Nationally Described Space StandardThe Nationally Described Space Standard sets minimum dwelling areas, bedroom dimensions, storage and ceiling-height requirements where it applies through planning policy. It is not a general building regulation, and London adds requirements of its own.09London housing design standards: outdoor space, ceiling heights, storageNew London homes must address internal space, ceiling height, storage and usable outdoor space together. London Plan D6 and its supporting guidance remain important, but specific housing-design guidance was withdrawn in March 2026 and should not be copied from an older checklist unchanged.10Accessible homes: M4(2) and M4(3)M4(2) covers accessible and adaptable dwellings, while M4(3) covers wheelchair-user dwellings. These optional building regulations requirements are normally activated through planning conditions; London Plan D7 sets the policy expectations for new homes, with specified qualifications.11Protecting neighbours: daylight, overlooking and privacyA new home should provide good living conditions without causing unacceptable harm to neighbours’ daylight, sunlight or privacy. The assessment is site-specific: a single separation distance or a rule-of-thumb angle cannot replace checking the actual buildings, windows and levels.12Parking, car-free development and cycle storageLondon parking provision depends on public transport accessibility, local policy and the type of development; car-free does not mean access and storage can be ignored. Residential cycle-parking guidance changed in March 2026, so use the current temporary standards rather than an unamended copy of the original London Plan table.13Refuse and recycling storageNew homes need adequate refuse and recycling storage with workable routes for residents and collection staff. Container types, capacity and the collection point must be checked with the local council; there is no single bin-store layout that can simply be copied to every London site.14Urban greening and trees on small sitesSmall-site landscaping should be planned with the buildings, drainage and existing trees, not added after the layout is fixed. London’s Urban Greening Factor, statutory Biodiversity Net Gain and tree or species protection are separate checks; passing one does not settle the others.
Building regulations for new homes
15The Future Homes Standard: what changes from March 2027The Future Homes Standard takes effect for new dwellings from 24 March 2027, subject to transitional rules, with separate arrangements for higher-risk building work from 24 September 2027. It strengthens energy and low-carbon services requirements; a planning permission alone does not establish which building regulations apply.16SAP calculations, energy statements and EPCsSAP calculations demonstrate a new home’s energy performance for building regulations, an energy statement addresses planning policy, and an EPC records the completed home’s energy rating. They can share information, but they are not interchangeable documents.17Overheating, EV charging, water efficiency and broadband in new homesNew homes must address overheating, water efficiency, charging infrastructure where the parking provisions apply, and broadband infrastructure and connectivity. These are separate building regulations checks, with different scopes and exceptions; passing the energy calculation does not complete them.18Sound and air tightness testingSound testing checks the performance of relevant separating walls and floors; air-tightness testing checks uncontrolled air leakage from the dwelling. They are different tests, and neither replaces the other: the required evidence depends on the construction and the applicable building regulations route.19Second staircases in residential buildings at least 18 metres highFrom 30 September 2026, Approved Document B’s guidance calls for more than one common stair in a block of flats where the top storey is 18 metres or more above ground level, subject to transitional provisions.20Higher-risk buildings and the Building Safety RegulatorA higher-risk residential building must use the Building Safety Regulator’s building control process rather than the ordinary choice of council or registered building control approver. Classification depends on height or storey count and use, and it brings approval, change-control and completion requirements that must be planned from the outset.
Delivery
21New-build warranties: NHBC, LABC Warranty, Premier and othersA new-build structural warranty provides the cover defined in its policy, not an unlimited guarantee that a home will never develop defects. Compare the actual cover, exclusions, inspection requirements and lender acceptance; NHBC, LABC Warranty and Premier Guarantee should not be treated as interchangeable simply because each offers a new-home product.22Professional Consultant's Certificate vs a structural warrantyA Professional Consultant’s Certificate records specified assurances and obligations from a qualified consultant; a structural warranty provides the insurance and other protection stated in its policy. They are not equivalent, and a lender may accept one arrangement but not the other.23Street naming and numberingApply to the local council for the official addresses of new homes rather than choosing postal numbers yourself. Street naming and numbering is a separate administrative process, and the approved address should be coordinated with Royal Mail, utility connections and the project’s final records.24Utility connections for new homesArrange new-home utilities as separate connection projects, coordinated with the building design and construction programme. Confirm the relevant operators, capacity, routes, permissions and inspection steps early; the presence of a nearby pipe or cable does not establish a ready connection for the new home.25Self-build and custom build: the Right to Build registerThe self-build and custom-build register records demand for people who want to build or commission their own home. Joining it contributes to the council’s statutory assessment of demand; it does not reserve a plot for you or grant planning permission.26VAT on new builds: zero rating and the DIY housebuilders' schemeQualifying construction of a new dwelling can be zero-rated for VAT, while an eligible private self-builder can reclaim VAT on qualifying materials through the DIY housebuilders’ scheme. These are different mechanisms: not every project cost is zero-rated or refundable.