Methods + costs by soiling type
London brick soiling sources: (1) carbon deposits from pre-1956 Clean Air Act coal smoke + post-1956 diesel — heaviest on south/west elevations + at first-floor level; (2) biological growth — algae, lichen, moss in damp shaded zones; (3) iron staining from corroded fixings; (4) salt efflorescence; (5) historic paint layers (1950s–80s emulsions, common in Notting Hill, Camden, Hackney). Cleaning methods 2026: (1) DOFF superheated steam (Stonehealth system, 150°C low-pressure 6 bar) — safest for soft London stock, removes carbon + biological + light paint, £18–£32/m² supplied scaffold-separate. Operator must be Stonehealth-trained — Owlsworth IJP, Stonehealth approved contractors, Cliveden Conservation. (2) TORC ThermaTech (rotating micro-abrasive vortex, dolomite or calcite media 50–250 micron) £24–£42/m² — for stubborn carbon + multi-layer paint; gentler than traditional grit blasting + does not damage soft brick face. (3) Chemical paint removal — Peelaway 1 (alkaline, for oil paints), Peelaway 7 (neutral, for emulsions), £45–£85/m² inc poultice removal + neutralisation rinse. (4) Hand-cleaning with stiff bristle + water for light biological soiling £8–£18/m². Methods to avoid: dry sandblasting (silica or grit) — destroys soft brick face in single pass, banned by Historic England + every London LPA on pre-1919 stock; acid wash (HF/HCl) — etches face, brings salts to surface, causes long-term spalling. Full façade cost example: 2-storey Victorian terrace front 65m² brick — DOFF clean £1,560 + £2,400 scaffold + £580 setup + £420 protection + access = £4,960 ex-VAT; with TORC paint removal upper sections add £1,200–£2,800.
LBC + CA approval + restoration scope
Restoration scope typically includes cleaning + repointing (see [[lime-mortar-vs-cement-pointing-london]]) + brick replacement + lintel + ironwork repair as one package — £12,500–£32,000 typical full-restoration Victorian terrace front. LBC: cleaning Grade II listed brickwork requires LBC application — method statement + sample panel approval + heritage statement. Determination 8 weeks. Refusal common for TORC abrasive on Grade I/II* — DOFF or hand-clean preferred. CA: pre-application advice recommended even though not LBC-required; some CAs (Westminster Belgravia, K&C, Hampstead) issue Article 4 directions removing PD rights on external cleaning. Building Notice required for any associated repointing >10m² typically. Insurance: specialist contractors carry £5M+ PI + £10M public liability — Builderr verifies pre-engagement. Sample panel: 1m² minimum sample on inconspicuous elevation before full works — 7-day cure observation period for any chemical residue or efflorescence. Programme: 65m² façade — sample 1 week + scaffold 2 days + clean 5–8 days + lime repointing 2 weeks + brick replacement 3–5 days + paint touch-up + reinstate joinery 1 week + scaffold strike = 5–7 weeks total. Best season: April–September (lime cure + dry conditions). Premium: scaffold-licensable Tower Hamlets, K&C, Westminster +£600–£1,200 for highways licence + Section 50 notices. Builderr default: photographic record + heritage statement filed with every CA façade clean for future-proof compliance audit trail.
