About the Chiswick House Conservation Area
The Chiswick House Conservation Area covers about 78 hectares and was designated by London Borough of Hounslow in 1977. Inside the boundary are 22 listed buildings (17 Grade I, 5 Grade II). The most significant is Cascade in Chiswick Park, 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.
Article 4 directions here
These overlap the conservation area. Householder directions remove more of the rights above; change-of-use ones don’t affect extending a house.
- Dwellinghouses (C3) to small HMOs (C4) - borough-wide Article 4 DirectionChange of use
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.
- Cascade in Chiswick ParkGrade I
- Chiswick HouseGrade I
- Chiswick House ConservatoryGrade I
- Classic bridge in Chiswick ParkGrade I
- Deer House in Chiswick Park Near Italian GardenGrade I
- Doric Column in Chiswick Park North East of ConservatoryGrade I
- Entrance Gateway of Chiswick Park Immediately West of ObeliskGrade I
- Hogarths House Wall and Gate of Hogarths HouseGrade I
- Inigo Jones's Gateway in Chiswick ParkGrade I
- Ionic Temple and Obelisk in Chiswick ParkGrade I
- Obelisk in Chiswick Park at End of Avenue Running West From TempleGrade I
- Ornaments Lining Avenue to Rear of Chiswick HouseGrade I
- Stone Entrance Piers in Front of Chiswick HouseGrade I
- Temple (rustic House) at End of Yew Walk North East of Chiswick HouseGrade I
- Ten Terms With Female Heads in Semicircle Before Front of Chiswick HouseGrade I
- Three Male Statues From Hadrian's Villa in Chiswick ParkGrade I
- Two Statues Flanking Chiswick HouseGrade I
- Chiswick House Lodge Opposite Corney RoadGrade II
- Chiswick Railway StationGrade II
- Entrance Gateway of Chiswick Park and Flanking Walls on Great West RoadGrade II
- Retaining Walls of Pond in Chiswick ParkGrade II
- Series of Urns in Italian Garden of Chiswick HouseGrade II
The council’s appraisal
WEBChiswick House Conservation Area AppraisalLondon Borough of Hounslow’s description of the area’s character — what planners look at when you apply.Open on council site ↗Nearby conservation areas
Boundary and listed buildings from London Borough of Hounslow and Historic England via planning.data.gov.uk (OGL). Guidance only — not an official council check.