About the Underhill Conservation Area 1 Conservation Area
The Underhill Conservation Area 1 Conservation Area covers about 32 hectares and was designated by Dorset Council in 1976. Inside the boundary are 65 listed buildings (1 Grade I, 3 Grade II*, 61 Grade II). The most significant is Portland Castle, Grade I. Part of the area lies in flood zone 3, so an extension may need a flood risk assessment.
What changes inside the conservation area
Conservation areas are “Article 2(3) land”. You keep most permitted development rights, but these are removed or tightened.
- Rear extensionElsewhere: 3 m · 6 m with PANo 6 m / 8 m prior approval
- Two-storey extensionElsewhere: 3 mNeeds planning permission
- Side extensionElsewhere: Half the widthNeeds planning permission
- Loft conversionElsewhere: 50 m³Needs planning permission
- Garden roomElsewhere: 2.5 m high by boundariesNot beside the house
- PorchElsewhere: 3 m²Same limits
- Solar panelsElsewhere: 0.2 m projectionSame limits
- Air source heat pumpElsewhere: 1 unitNot facing the road
- Fences, walls and gatesElsewhere: 2 m · 1 m by a roadSame limits
- External claddingElsewhere: Matching materialsNeeds planning permission
- Tree workElsewhere: No notice6 weeks’ notice to the council
- Demolition (over 115 m³)Elsewhere: AllowedNeeds planning permission
Limits for a semi-detached house under the GPDO 2015. An Article 4 direction can remove more.
Listed buildings in the conservation area
Any work affecting these needs listed building consent, inside or out. Each links to its entry on the National Heritage List.
- Portland CastleGrade I
- Captain's HouseGrade II*
- Gateway and Curtain Wall to South East of Captain's HouseGrade II*
- Queen Anne House With Boundary Wall and Gate PiersGrade II*
- 1 and 2 With Boundary Wall and StepsGrade II
- 1 CastletownGrade II
- 10 and Attached OutbuildingGrade II
- 107 and 109, High StreetGrade II
- 120, ChiswellGrade II
- 135 With Front Boundary WallGrade II
- 137 and 139 With Front Boundary WallGrade II
- 139 With Boundary WallGrade II
- 141 With Boundary Walls, Piers and GateGrade II
- 147, High StreetGrade II
- 159 and 161, High StreetGrade II
- 165, FortuneswellGrade II
- 165, High StreetGrade II
- 17, MallamsGrade II
- 185, Brandy LaneGrade II
- 187 and 189, Brandy LaneGrade II
- 19, MallamsGrade II
- 193, Brandy LaneGrade II
- 195 and 197, Brandy LaneGrade II
- 199, Brandy LaneGrade II
Show all 65 listed buildings ↓All 65 listed buildings
- 3, With Boundary WallGrade II
- 42, MallamsGrade II
- 53, MallamsGrade II
- 58, High StreetGrade II
- 58, MallamsGrade II
- 59 and 61, FortuneswellGrade II
- 6 and 8, FortuneswellGrade II
- 60 and Attached OutbuildingGrade II
- 60, MallamsGrade II
- 62 and 64, MallamsGrade II
- 81, FortuneswellGrade II
- 86, ChiswellGrade II
- 90 and 92, ChiswellGrade II
- Boundary Stone Circa 23 Metres South of Entrance to Captain's HouseGrade II
- Bow Cottage, With Boundary WallGrade II
- Church of St JohnGrade II
- Churchyard Walls and Piers to Church of St JohnGrade II
- Conjuror's LodgeGrade II
- Cottage Adjoining East Side of No 189Grade II
- Dolphin Dolphin and Neptune With Attached Rear Boundary Wall NeptuneGrade II
- Fair WindsGrade II
- Former Portland Steam LaundryGrade II
- Front Boundary Wall and Steps to Police StationGrade II
- K6 Telephone Kiosk Opposite No 63Grade II
- Little ShipGrade II
- Maiden WellGrade II
- New Star InnGrade II
- No 163 With Front Boundary WallGrade II
- Nos 116 and 118 Including Front Garden Walls and GatepiersGrade II
- Police Station With Court RoomGrade II
- Post OfficeGrade II
- Ranters' Lodge, With Enclosing WallGrade II
- Royal Breakwater HotelGrade II
- Royal Portland ArmsGrade II
- Royal Victoria HotelGrade II
- TenastelionGrade II
- The Britannia InnGrade II
- The Captain's House and Attached Wall to South EastGrade II
- The Cove House InnGrade II
- Two Monuments Approximately 5 Metres North East From West Tower of Church of St JohnGrade II
- Workshop Adjoining No 46 (not Included)Grade II
Streets in the conservation area
Streets with listed buildings inside the boundary. Boundaries often split a street — check your exact address.
Nearby conservation areas
Boundary and listed buildings from Dorset Council and Historic England via planning.data.gov.uk (OGL). Guidance only — not an official council check.