Case study
Muswell Hill — a Victorian semi taken back to structure and reconfigured as four compliant flats
A run-down Victorian semi in Muswell Hill, taken right back to its structure and rebuilt as four self-contained, building-regs-compliant flats. The programme did the heavy lifting — a basement conversion, a rear extension, and a loft expansion under an enlarged dormer, all phased so the scheme could progress floor by floor rather than stopping the building dead. Four homes where there was one tired house, delivered to a plan and to the numbers.
Project at a glance
| Location | Muswell Hill, N10 |
| Property type | Victorian house |
| Project type | Four-flat conversion |
| Programme | 234 working days (phased) |
| Investment | circa £450k (guideline) |
| Architect | Nick Timson — TGN Architects |
The brief
Nick works in flood prevention, so the brief was technical from the outset: a building that performed correctly across compliance, fire, services and structure, with no finish that betrayed its commercial purpose. The investment case rested on getting the upper units rentable while works continued below.
Existing building structurally sound but stripped of margin. Full internal strip-out back to structure. Scope included basement conversion, rear extension at ground floor, loft expansion with dormer enlargement, and full reconfiguration into four self-contained units. Part B fire compartmentation, Part E acoustic separation between units, and Part L thermal upgrades required for four separately-let dwellings. Architect engaged from the start. Access to rear and roof tight, no side return.
The build
Two-phase delivery. Phase 1 was strip-out and structural — steel installation and load redistribution including the roof-level beam that had to thread past a retained chimney with restricted access. Phase 2 prioritised the upper-floor flats so they could be let and generate rental income while remaining works continued below. Every trade booked in a window narrow enough to keep the live let undisturbed.
Structural alterations to create separate access routes. Part B compliant lobbies between units, with thirty-minute fire-rated doors specified to the architect’s drawing. Acoustic separation built up in three layers between floors: resilient bars, mass-loaded vinyl, mineral wool, plus floating timber finish above. The Part E target met by the third tested separation.
Services rerun on a per-unit basis. Four electricity supplies, four water meters, four gas connections, coordinated with the utility company over six months of phased switchovers. The roof envelope was left in place. Insulation was upgraded internally to hit Part L while keeping the floor-to-ceiling heights compliant — the cost case ruled out opening the roof.
Credits
Designed by Nick Timson of TGN Architects.
A Victorian house taken back to structure and rebuilt as four self-contained flats, on a phased programme that let the upper flats earn while the lower works continued — 234 working days.
