When you need landlord consent
Almost all standard leases require consent for: any structural alterations (load-bearing walls, RSJs, foundations); changes to plumbing, drainage or gas beyond like-for-like; new electrical circuits or distribution board changes; flooring buildup changes (impact on Part E sound insulation between flats); new ventilation ducting; window or external door changes. Some leases require consent for any work over £5k. Decoration, kitchen replacement in same position and bathroom suite swaps usually don't need consent.
Documents the freeholder will ask for
Standard pack: planning drawings (existing + proposed); structural engineer's calculations and detail drawings for any openings; M&E schematic showing new services routes; sound insulation specification confirming Part E compliance for floor buildup changes; method statement covering Party Wall service to other flats; contractor's public liability insurance certificate (typically £5m minimum) and references; build programme. Larger freeholders may require contractor pre-vetting.
Reasonable vs unreasonable refusal
Most leases have qualified covenants — consent cannot be unreasonably withheld (Landlord and Tenant Act 1927 s.19). Reasonable grounds: structural risk to the building, fire compartmentation breach, inadequate sound insulation, lease term too short. Unreasonable grounds: aesthetic preference, blanket no-renovation policies, demands for excessive deed of variation premium. If refused unreasonably, leaseholder can apply to First-tier Tribunal (Property Chamber).
