Listed Georgian townhouse whole-house restoration, SE3

Brief

An 1812 Grade II listed Georgian terraced townhouse in Blackheath conservation area SE3 — first listed in 1972 as part of Blackheath terrace group listing. 5-storey including lower-ground and attic; 198m² across five floors; original sash windows, marble fireplaces, ornate cornicing and ceiling roses; previous 1990s 'modernisation' had stripped many features and installed sympathetic-but-incorrect detailing. Clients: a barrister and barristers' clerk relocating from St John's Wood with two teenage children; 25-year hold intended. Brief: full LBC heritage restoration — reverse the 1990s damage, restore lost period features, modernise services to contemporary comfort, and add deep-retrofit fabric improvements where LBC permits. Budget £425k. Lewisham borough first Grade II restoration in Builderr portfolio.

Challenge

Four interlocked LBC challenges. (1) Original sash windows: 11 original Georgian 6-over-6 sashes with crown glass surviving in 5; 1990s replacement uPVC in 6 had to be removed and replaced with reproduction crown-glass sashes matching profile, cill, glazing bar dimensions exactly — Mumford & Wood Conservation Series specified at £2,800–£3,500 per window. LBC requested historic profile sample for approval. (2) Cornice and ceiling rose restoration: 4 of 8 reception room ceilings retained original cornice; 3 had been over-skimmed in 1990s (cornice profile lost beneath plaster); 1 had been replaced with off-the-shelf coving — full replication required. Run-in-situ cornice replication by Hayles & Howe (Bristol) at £180–£280 per linear metre × ~88m total = £18,500. (3) Marble fireplaces: 4 original marble fireplaces had been removed (3) or boxed in (1) during 1990s; sourcing matching period replacements from Lassco and Westland (London architectural salvage) £4,500–£8,500 per fireplace + installation. (4) Lower-ground kitchen: original 1812 kitchen footprint with Welsh slate floor; 1990s install had ripped out floor and installed concrete + tile. LBC required restoration of original character even though kitchen is functional space. Solution: honed Yorkstone floor (LBC approved as period-appropriate alternative), concealed appliances behind bespoke joinery matching original cabinet style.

Solution

Pre-construction phase (16 weeks): heritage statement, photographic survey, conservation architect (Donald Insall Associates), structural engineer (Mason Navarro Pledge), MEP consultant. LBC application submitted to Lewisham conservation team with 32 drawings, condition surveys per element, restoration specifications. LBC granted at week 14 with 11 conditions (reproduction sashes to approved profile, run-in-situ cornice to historic sample, salvaged or Lassco-supplied fireplaces, no Crittall internal screens, no MVHR ductwork through main rooms, secondary glazing limited to Selectaglaze Series 70 profile, lower-ground floor in Yorkstone only, no painted brickwork externally, no LED downlight ceiling penetrations in reception rooms, no air-conditioning visible from public realm). Build programme weeks 1–32. Weeks 1–6: strip-out (carefully, retaining all salvageable elements); structural survey at each floor; replacement of timber sash beams with steel where rotten; new cellar damp-proofing with breathable lime render. Weeks 7–14: 11 sash windows out (uPVC 6 disposed of; original 5 sent to Ventrolla for refurbishment £1,200–£1,800 each); 6 Mumford & Wood reproduction sashes manufactured to LBC-approved profile (lead time 8 weeks); Selectaglaze Series 70 secondary glazing internally on all 11. Weeks 15–22: cornice replication by Hayles & Howe (88m run-in-situ at £180–£280/lm = £18,500; 8 ceiling roses replicated/restored £350–£550 each); marble fireplaces sourced from Lassco (3) and Westland (1) £6,500 average each + installation; replacement original-spec ironmongery (Joseph Giles, Lassco, Hodes); restored shutters (paint-stripped, structurally repaired, re-fitted). Weeks 23–28: full rewire (concealed in skirting voids, no LBC objection); new plumbing (concealed in service voids, no chase work in original walls); new boiler (mains gas — LBC permitted, no ASHP visible from front; refused for principal elevation); new bathrooms × 3 (Crosswater Belgravia Victorian style with brass fittings); kitchen install (bespoke Smallbone of Devizes in Farrow & Ball Cooking Apple Green; concealed Miele appliances). Weeks 29–32: decoration (Farrow & Ball heritage palette: Pink Ground, Off-White, Dimity, Studio Green; lime distemper on lath-and-plaster); snagging. Lewisham LBC compliance certificate week 33; building control completion week 34.

Outcome

Full LBC restoration delivered to Donald Insall Associates conservation standard; all 11 LBC conditions discharged. 11 sash windows: 5 original restored, 6 reproduction Mumford & Wood replacing 1990s uPVC; Selectaglaze secondary glazing to all 11 reducing traffic noise from Blackheath Road by 24 dB measured. Cornice and ceiling roses: 88m run-in-situ Hayles & Howe replication completed; matches original 1812 profile precisely. Marble fireplaces: 4 sourced and installed — 3 Lassco, 1 Westland; restored marble cleaned and re-polished; 4 cast-iron Victorian inserts (a 1850s upgrade, retained as part of heritage layered story). EPC F (37) → D (66) — constrained by retained Georgian sash glazing (secondary only) and lack of internal wall insulation (LBC refused on grounds of lath-and-plaster preservation); D achievable; A or B impossible without compromising LBC. Property valuation: pre-restoration £1,450,000 (Grade II listed Blackheath terrace, undervalued by 1990s 'modernisation'); post-restoration £2,180,000 (£730,000 uplift on £425k build cost — 172% gross ROI). Lewisham first Grade II restoration. Project featured in Historic England casework note as exemplar reverse-of-1990s-damage project; LBC team's praise has expedited future heritage applications from Builderr.