Conversion Flat Renovation in London

Renovating Flats in Converted Period Buildings

Conversion flats—created by dividing Victorian, Edwardian, or Georgian houses into separate residences—offer period charm and character at a more affordable price than a whole house. However, renovating these flats comes with unique challenges: freeholder permissions, building regulations, soundproofing requirements, and working within existing structures.

Hampstead Renovations specialises in conversion flat renovations across North London. This guide covers permissions, planning, soundproofing, common projects, and practical considerations for improving your period flat.

Understanding Conversion Flats

Types of Conversion

• Garden flat: Ground floor or basement, usually with private garden access
• Raised ground floor: Slightly elevated, often with bay windows
• First floor: Typically the best rooms of the original house
• Top floor/maisonette: Upper floors, may include loft space
• Purpose-built conversions: Professionally designed multi-unit buildings
• Informal conversions: Older, sometimes poorly executed divisions

Ownership Structures

• Leasehold: You own the flat for a set period (99, 125, 999 years)
• Freeholder: Owns the building, grants leases
• Share of freehold: Flat owners collectively own the building
• Right to Manage (RTM): Leaseholders control building management

Permissions and Restrictions

Lease Restrictions

Always check your lease before starting any work:

• Structural alterations: Usually require freeholder consent
• Flooring: Often must be carpet or have soundproofing
• Noise restrictions: Limits on when noisy work can be done
• External changes: Usually prohibited (windows, doors, balconies)
• Shared services: Can't alter pipes/wires serving other flats

Freeholder Consent

Typically required for:

• Removing or adding walls
• Changing floor coverings
• Bathroom or kitchen relocations
• New heating systems
• Any work affecting structure or shared services

Process:

• Submit detailed plans and specifications
• May require surveyor's report
• Freeholder can charge admin fee (£50-£300)
• Response time: 4-8 weeks typically
• Can refuse unreasonably - legal recourse available

Planning Permission

• Usually not needed for internal alterations
• Required for external changes (new windows, balconies)
• Conservation areas have stricter rules
• Listed buildings need consent for any alterations

Building Regulations

Required for:

• Structural changes (wall removal, new openings)
• New bathrooms or moving existing ones
• Electrical work (full rewires)
• Soundproofing improvements (between flats)
• Fire safety works

Soundproofing Requirements

Building Regulations Part E

If renovation involves work between flats, must meet sound insulation standards:

• Airborne sound: Voices, TV, music (45 dB reduction minimum)
• Impact sound: Footsteps, dropped objects (62 dB maximum)
• Testing: May require professional acoustic testing

Floor Soundproofing

Essential if flat has another flat above or below:

• Acoustic underlay: Beneath carpet or wood (£15-£40 per m²)
• Floating floor: Decoupled from joists (£40-£80 per m²)
• Mass-loaded vinyl: Dense sound barrier layer
• Resilient bars: Under ceiling to reduce transmission
• Acoustic insulation: Mineral wool between joists

Wall Soundproofing

• Acoustic plasterboard: Denser than standard (£25-£50 per m²)
• Independent stud wall: Not touching party wall (£60-£100 per m²)
• Mass and isolation: Principle of effective soundproofing

Common Conversion Flat Projects

Kitchen Renovation

Often small and awkwardly shaped:

• Galley layout: Make most of narrow spaces
• Compact appliances: Slimline dishwashers, combination ovens
• Maximise storage: Floor-to-ceiling units, corner solutions
• Relocating: Expensive (new plumbing, drainage, ventilation)
• Cost: £8,000-£25,000

Bathroom Upgrades

• Small bathroom solutions: Wall-hung toilets, corner sinks, shower over bath
• En-suite creation: Often possible from bedroom space
• Drainage challenges: May need macerator pump if gravity drainage difficult
• Ventilation: Extractor fan essential (often no window)
• Cost: £5,000-£15,000

Opening Up Spaces

Create more open-plan living:

• Kitchen-living: Remove wall between kitchen and reception
• Structural survey: Determine if wall is load-bearing
• RSJ installation: Steel beam supports ceiling
• Building Regs: Required for structural work
• Freeholder consent: Usually needed
• Cost: £3,000-£8,000

Loft Conversion (Top Floor Flats)

• Only possible if you own the loft space (check lease)
• Freeholder consent essential
• May need to grant other leaseholders access (pipes/wiring)
• Fire escape requirements stricter for flats
• Cost: £35,000-£60,000

Storage Solutions

Maximising limited space:

• Built-in wardrobes: Floor-to-ceiling, alcove utilisation
• Under-stair storage: If you have a maisonette
• Utilise height: High-level cupboards
• Multi-functional furniture: Ottoman beds, storage benches

Preserving Period Features

Worth Keeping

• Fireplaces: Central feature, adds value
• Ceiling roses and coving: Period character
• Sash windows: Original to building
• Floorboards: Can be sanded and refinished
• Picture rails: Characteristic detail
• Panel doors: Often beautiful timber

Restoration vs. Removal

• Original features add value and character
• Often cheaper to restore than replace
• Consider neighbours' flats (maintaining consistency)
• Listed buildings: removal may be prohibited

Services and Infrastructure

Electrics

• Separate supply: Each flat should have own consumer unit
• Rewiring: Typical if pre-1980s (£3,000-£6,000)
• Shared meter cupboard: Usually in communal area
• Access for work: May need to notify neighbours

Plumbing

• Shared soil stack: Drainage shared with other flats
• Water pressure: May be low in upper flats (pump solution)
• Mains water: Usually via shared rising main
• Boiler location: Often limited by flue route

Heating

• Individual boilers: Most flats have separate systems
• Communal heating: Some conversions have shared boiler (can't change)
• Flue requirements: New boilers need external flue (consent needed)
• Underfloor heating: Good for flats (space-saving, efficient)

Fire Safety

Current Requirements

• Fire doors: 30-minute rated doors to flats
• Smoke alarms: Interlinked alarms in each flat
• Escape routes: Communal stairs must be clear
• Fire stopping: Seal penetrations between flats

Post-Grenfell Regulations

• EWS1 certificates for external wall systems
• Enhanced fire safety for buildings over 11m
• Your freeholder's responsibility, but affects flat value

Maximising Space

Layout Optimisation

• Open-plan: Remove non-structural walls
• Multi-functional rooms: Living/dining, bedroom/office
• Pocket doors: Sliding doors save swing space
• Built-in furniture: Maximises usable floor area

Light and Space

• Mirrors: Reflect light, make spaces feel larger
• Pale colours: Walls and ceilings
• Repair sash windows: Maximise natural light
• Glass internal doors: Borrow light between rooms

Budget Planning

Cosmetic Refresh (£10,000 - £25,000)

1-bed conversion flat:

• Full redecoration
• New bathroom
• Kitchen refresh (new doors, worktop, appliances)
• Flooring throughout
• No structural changes

Comprehensive Renovation (£30,000 - £60,000)

2-bed conversion flat:

• New kitchen and bathroom
• Rewire and replumb
• New heating system
• Soundproofing floors
• Open-plan living (wall removal)
• Full redecoration

High-End Refurbishment (£60,000 - £120,000+)

• Everything in comprehensive, plus:
• Bespoke kitchen
• Luxury bathroom(s)
• Extensive soundproofing
• Smart home systems
• High-spec finishes throughout
• Built-in storage solutions

Hidden Costs

• Freeholder fees: £50-£300 per consent
• Party Wall Awards: £700-£1,500 if work affects neighbours
• Acoustic testing: £400-£800
• Building Regs: £500-£1,500
• Access issues: Narrow stairs, no lift (increased labour costs)

Working Considerations

Access and Logistics

• Narrow staircases: Difficult to get materials/waste up/down
• No lift: Manual handling of everything
• Shared entrance: Keep communal areas clean and clear
• Parking: Limited space for contractor vehicles/skips
• Working hours: Respect neighbours (typically 8am-6pm Monday-Friday)

Neighbour Relations

• Inform neighbours before starting work
• Provide contact details and schedule
• Minimise noise during sensitive times
• Keep shared spaces clean
• Address complaints promptly

Adding Value

Best ROI Improvements

• Modern kitchen and bathroom: 60-80% return
• Additional bedroom: Significant value increase
• En-suite bathroom: Highly desirable
• Improved energy efficiency: Better EPC rating
• Period feature restoration: Appeals to buyers

Less Valuable

• Over-specification (luxury beyond area norm)
• Removing period features
• Unusual layouts or colour schemes

Timeline

Full Flat Renovation (1-2 Bed)

• Design and consents: 6-10 weeks
• Strip out: 1 week
• First fix: 2-3 weeks
• Second fix: 3-4 weeks
• Finishing: 2-3 weeks
• Total: 3-5 months typical

Contact Hampstead Renovations