Listed building consent for internal alterations

The short answer

Section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires consent for any works of demolition, alteration or extension that would affect the character of a listed building as a building of special architectural or historic interest. There is no internal/external distinction in the statute: a partition wall, a chimney breast, an architrave, a staircase balustrade and a decorative cornice are each protected to the same standard as the front elevation.

The statutory basis for internal control

The listing description on the National Heritage List for England is an aid to identification, not a limit on protection. The Court of Appeal in Debenhams plc v Westminster City Council (1987) confirmed that the entire building is listed unless the entry expressly excludes a part. Curtilage structures pre-dating 1 July 1948 are also caught under section 1(5). The internal control regime flows from this.

Plan form: the single most-protected internal feature

Plan form, the arrangement of rooms, the position of staircases, the routes of circulation, is the most heavily protected internal characteristic in London terraced casework. Removal of a spine wall to create open-plan living is the most refused single alteration in the Grade II terrace inventory. Officers treat plan form as evidence of the building's original social and constructional logic, and they expect changes either to be avoided or to be justified with a structured public benefit argument under NPPF paragraph 208.

Joinery, doors and architraves

Historic six-panel doors, moulded architraves, dado rails, picture rails, skirting boards and staircase balustrades are part of the special interest. Replacement, even like-for-like, is alteration and needs consent. Repair (splice repair to a damaged section, refixing a loose architrave) is repair and does not.

Fireplaces, chimney breasts and flues

Removal of a chimney breast is almost always refused, including on upper storeys. The chimney is structurally and historically integral to the building. Reinstatement of a missing fireplace is generally encouraged; replacement of a surviving period chimneypiece with a modern unit needs consent and is usually refused on Grade II* and Grade I.

Decorative schemes, plasterwork and panelling

Historic plaster cornices, ceiling roses, dado panelling and run-in-situ enrichments are part of the listing. Stripping wallpaper is repair; stripping historic plaster back to brick is alteration. Polychrome decorative schemes (Victorian, Aesthetic Movement, Arts and Crafts) discovered during works require pause and a heritage view.

Services routed inside the building

New socket positions, lighting circuits, smoke detection wiring, surface-mounted gas runs and underfloor heating overlays are alteration. The practical pattern: minimise chases into historic plaster, surface-mount in painted conduit where possible, and lift floorboards by careful numbered removal and replacement.

Evidence officers want to see

A measured survey, an existing-and-proposed plan set, a photographic record of affected features, a proportionate heritage statement (typically five to fifteen pages on a Grade II terrace) and a method statement for any sensitive removal or making-good operation. Outbound references conservation officers expect to see cited: the relevant 1990 Act, the Historic England planning advice and the relevant NPPF heritage paragraphs.