Maximum extension sizes without planning permission — applied to London Borough of Hammersmith and Fulham in the Greater London. With intensive Gateway 3 sign-off and HRB oversight and an average build cost of £3100/sqm, the deal arithmetic for permitted Development Extensions here is distinct from neighbouring boroughs.
Heads up: London Borough of Hammersmith and Fulham operates Article 4 directions, so permitted Development Extensions that would normally be permitted development will likely require a full planning application here. Build that into your timeline and risk model.
Run any Greater London listing through Scapely to get a property-specific build cost, council objection-risk score and the AI Objection Risk Analyzer overlay applied to London Borough of Hammersmith and Fulham's policy environment.
More on Permitted Development Extensions · More on London Borough of Hammersmith and Fulham