Class G scope + qualifying criteria + High Street + mixed-use London context
Class G of Part 3 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 covers mixed-use buildings where there is existing C3 residential at upper floors + Class E commercial at ground floor (typical London Victorian/Edwardian terraced High Street + parade unit). Class G specifically permits: (i) change of use of the Class E ground-floor unit to add C3 (creating an additional self-contained flat at ground floor while retaining first-floor + above flat) — i.e. shop-with-flat-above becomes two-flats (one ground + one above); OR (ii) extension/alteration of the existing C3 flat into the Class E ground floor space (creating a maisonette where one flat spans ground + first); OR (iii) change of use of the Class E ground floor to ancillary use of the existing C3 flat (storage + garden access + parking + cycle store) for the upper-floor flat. Distinct from Class MA which converts entire building Class E → C3. Class G qualifying criteria: (1) Building must be mixed-use — at least one Class E + at least one C3 in same planning unit immediately before application; (2) Class E use must have been current for at least 2 years; (3) Total resulting floor area limit — not capped explicitly under Class G in the same way as Class MA (1,500m²) but converted C3 must comply with NDSS + natural-light + noise + flood/contamination tests; (4) Not within listed building curtilage; (5) Article 4 directions may apply — Westminster, K&C, Camden, Islington + 20+ boroughs Article 4 over Town Centre + High Street designations restricting Class G; (6) Outside SSSI + AONB. London High Street context: 25,000+ terraced retail-with-flat-above units across London Victorian + Edwardian parades (Wood Green High Road, Holloway Road, Mile End Road, Lavender Hill, Battersea Park Road, Brixton High Street, Camberwell Road, Peckham Rye, Crystal Palace Triangle, Streatham High Road, Wandsworth High Street, Putney High Street, Hammersmith Broadway, Goldhawk Road, Shepherd's Bush Market, Notting Hill Gate, Kilburn High Road, West End Lane West Hampstead, Crouch End Broadway, Muswell Hill Broadway, Hornsey Road, Stoke Newington High Street, Kingsland Road, Mare Street, Roman Road, Bow Road, Mile End Road, Whitechapel Road, Commercial Road, Cable Street, Old Kent Road, Walworth Road, East Street, Lordship Lane, Forest Hill Road, Sydenham Road, Bromley High Street, Petts Wood Square, Beckenham High Street, Croydon High Street, Sutton High Street, Wimbledon Broadway, Tooting High Street, Balham High Road, Clapham High Street, Northcote Road) — each containing 80–400 mixed-use units. Investment landscape: Class G enables additional flat creation on a single building cost £140–£280k all-in for ground-floor flat conversion (vs £350k+ acquiring + converting separate building) — typical ground-floor flat creation £180–£240k delivering £325k–£475k value uplift in zone 2–3 London = 65–110% gross ROI on conversion cost. Critical economic driver: rising demand for affordable urban flats + falling Class E retail/leisure demand post-2020 + Local Plan policies (London Plan 2021 H4 Spatial Strategy) encouraging mixed-use intensification on Town Centres + High Streets. Builderr typical Class G client: small landlord with single mixed-use Victorian terrace freehold + existing 2-bed flat above + struggling/vacant shop unit + seeking to recover £30–£90k/year in lost shop rent via additional flat creation generating £18–£28k/year rental + £180–£350k capital uplift on refinance.
Class G prior approval process + Building Regulations + Builderr workflow
Class G prior approval submission requires: (1) Application Form (Class G PA) + £258 fee; (2) Site location plan 1:1250 + block plan 1:500 + ownership certificate (Certificate A if sole owner; B if leasehold/sub-tenant); (3) Existing floor plans 1:100 — clearly delineating Class E ground floor + existing C3 first/second floor; (4) Proposed floor plans 1:100 — new C3 ground floor flat layout + retained C3 above + separate communal entrance + service connections + cycle + refuse store; (5) Elevations existing + proposed — typically minimal change to shopfront if retained as glazed living room or shopfront-conversion to dual-aspect window with brick infill (LPA conservation overlay sensitive); (6) Class E use evidence 2+ years (business rates + lease + landlord statement); (7) Flood risk assessment Flood Zone 2/3; (8) Contamination Phase 1 desktop (former dry cleaner, garage, petrol station, photographic studio = Phase 2 typically required); (9) Noise impact assessment if ground-floor flat sharing party wall with operating Class E uses (adjacent pub, takeaway, restaurant — Pro PG ANC 2017 + BS 8233:2014); (10) Natural light report — single-aspect rear flats common (no rear elevation light or only light well 3–4m deep) — BRE 209 daylight factor often borderline + risk of refusal — frequently requires light well excavation + skylight installation in rear extension; (11) NDSS — typical Class G ground-floor flat 1b1p 39m² minimum + ceiling height 2.3m + storage 1.5m² + separate entrance from upstairs flat (entrance lobby pinch-point on Victorian terraced shop — typically requires shopfront entrance retained + side passage entrance with FD30S to flat 1 + separate staircase or front entrance partition; (12) Service separation — Class G ground-floor flat needs separate electricity meter + gas meter + water meter + drainage + heating + fire alarm + post box from upstairs flat (FD30S + acoustic Part E + boundary fire-rated party wall + separate front door + lobby + bin store); (13) Transport — typically minimal as 1 flat addition + zone 2–3 London public transport accessible. LPA prior approval decision 8 weeks. Refusal grounds same as Class MA paragraph MA.2 (flood, contamination, noise, transport, natural light, NDSS). Builderr Class G workflow: Month 0 — pre-app desktop (£450) + Article 4 check + planning history + business rates evidence; Month 0–1 — daylight feasibility (£950) + NDSS layout feasibility (£450) + structural feasibility (party wall + bearing wall removal + lintel); Month 1–2 — prior approval submission with optimisation; Month 2–4 — 8-week determination; Month 4–6 — Building Regulations Notice/Full Plans + Party Wall Awards + Tender + tenant relocation; Month 6–10 — Build (typical 14–18 weeks ground-floor flat from existing shop unit); Month 10–11 — Commissioning + EPC + Part E acoustic test + Part F ventilation + EICR + Gas Safety + Council Tax registration. Building Regulations critical detail on Class G ground-floor flat: (a) Part E separating floor + party wall — full sound test (52dB airborne + 58dB impact minimum); (b) Part B fire safety — FD30S front door from communal entrance + 30-min compartmentation between Class E + C3 + 30-min between adjoining premises + Grade D smoke alarm + carbon monoxide alarm; (c) Part L energy — typically EPC C minimum target — ASHP retrofit feasibility on tight footprint typically blocked by acoustic neighbour concerns + cost — gas combi typically retained with thermostatic radiator valves + insulation upgrade; (d) Part F ventilation — kitchen 30L/s extract + bathroom 15L/s + background ventilation; (e) Part K + M accessibility — flush threshold + 800mm wide doors + 1.5m turning circle in living room. Typical Builderr Class G ground-floor flat cost breakdown: £180,000 build + £6,500 prior approval + design + structural + £8,500 Party Wall × 2 (adjoining shops) + £4,500 fire engineer + £3,500 acoustic engineer + £6,000 utilities separation + £25,000 contingency = £234,000 all-in. Post-conversion RICS valuation typical zone 2–3 London Victorian terrace ground-floor 1-bed conversion: £325–£475k. Capital uplift £85–£241k + rental £18–£28k/year. Refinance route typically 70% LTV on enhanced building valuation extracting £180–£280k working capital. See [[class-ma-office-to-residential-conversion-london]] + [[mains-water-pressure-london-low-pressure-fix]] + [[shopfront-conversion-london-class-g]] + [[party-wall-act-explained-london]] + [[nationally-described-space-standards-class-ma-london]].
