Planning: permitted development or not? (England)
check_permitted_developmentChecks a householder project in England against the permitted development limits in the GPDO 2015, Schedule 2, Part 1: single and multi storey rear extensions, side and wraparound extensions (Class A), loft dormers and hip to gable (Class B), rooflights (Class C), porches (Class D), outbuildings and garden rooms (Class E), and adding storeys (Class AA). Returns verdict (permitted_development, prior_approval_route, needs_planning_permission, needs_listed_building_consent, check_article_4_or_condition, needs_more_info, not_covered), answer, one line per limit in checks (status pass, fail or needs_input, with the limit and the rule's paragraph), the larger home extension prior approval route when a single storey rear extension is 3 to 6 m (attached) or 4 to 8 m (detached), flags for conservation areas, National Parks, National Landscapes, listed buildings and Article 4, must_confirm and sources. Example: 3.5 m single storey rear extension on a semi, 3.8 m high: {"project":"rear_extension_single_storey","house_type":"semi_detached","depth_m":3.5,"height_m":3.8,"eaves_height_m":2.8,"within_2m_of_boundary":true,"curtilage_coverage_percent":20,"materials_similar":true,"higher_than_existing_roof":false,"eaves_higher_than_existing":false,"beyond_principal_or_highway_side_elevation":false,"balcony_veranda_or_raised_platform":false}.
Tool call template
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"project": "<project>"
},
"name": "check_permitted_development"
}
}Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| trade | No | Optional. The builder's own business details (Nero Trade Profile v1). Used to prefill the contractor details in notices and CDM answers and to give a stable nero_trade_ref. Not stored by Site Pack. | |
| nation | No | Defaults to england. Only england is checked; others return not_covered. | |
| depth_m | No | Rear extensions: how far it projects beyond the rear wall of the ORIGINAL house, metres. | |
| project | Yes | ||
| storeys | No | Storeys in the extension or outbuilding. | |
| width_m | No | Side extensions: width of the extension. | |
| cladding | No | Article 2(3) land: will the outside be clad in stone, render, pebble dash, timber, plastic or tiles? | |
| height_m | No | Highest point of the extension, porch or outbuilding above ground, metres. | |
| roof_type | No | Outbuildings: dual pitched allows 4 m (if not within 2 m of a boundary). | |
| house_type | No | Needed for rear extensions (4 m detached, 3 m otherwise) and lofts (40 m3 terraced or end terrace, 50 m3 otherwise). | |
| designations | No | Any that apply at the address. national_landscape is the new name for an AONB. Leave empty if none. | |
| hip_to_gable | No | Lofts: is it a hip to gable (no eaves set back needed)? | |
| protrusion_m | No | Rooflights: how far it stands proud of the roof slope, metres. | |
| floor_area_m2 | No | Porches: external ground floor area. Outbuildings: footprint. | |
| property_kind | No | Defaults to house. Flats and maisonettes have no householder permitted development. | |
| eaves_height_m | No | Eaves height, metres. | |
| added_volume_m3 | No | Lofts: extra roof space volume including any earlier roof enlargements, m3. | |
| eaves_setback_m | No | Lofts: dormer set back from the eaves along the slope, metres (at least 0.2). | |
| materials_similar | No | External materials look similar to the house. | |
| roof_pitch_matches | No | Multi storey: roof pitch matches the house as far as practical. | |
| distance_from_house_m | No | Outbuildings in National Parks, National Landscapes, the Broads or World Heritage Sites. | |
| within_2m_of_boundary | No | ||
| original_house_width_m | No | Side extensions: width of the original house. | |
| higher_than_existing_roof | No | ||
| curtilage_coverage_percent | No | After the work: ground covered by all buildings other than the original house, as a % of the plot excluding the original house footprint. | |
| eaves_higher_than_existing | No | ||
| distance_to_rear_boundary_m | No | Multi storey rear extensions: distance from the extension to the boundary opposite the rear wall. | |
| on_front_slope_facing_highway | No | Lofts: does the dormer go on the front roof slope facing a road? | |
| between_side_wall_and_boundary | No | Outbuildings on Article 2(3) land. | |
| distance_to_highway_boundary_m | No | Porches: distance to the boundary with a road or footway. | |
| forward_of_principal_elevation | No | Outbuildings: in front of the house's front wall? | |
| side_windows_obscure_and_fixed | No | Upper floor or roof windows in a side wall are obscure glazed and non-opening below 1.7 m. | |
| balcony_veranda_or_raised_platform | No | Includes a balcony, veranda, or a raised platform (decking) over 0.3 m high. | |
| used_for_sleeping_or_separate_home | No | ||
| beyond_principal_or_highway_side_elevation | No | Does it go forward of the front (principal) wall, or of a side wall facing a road? |