Can Flats in London Get Extensions? Leaseholder Rights and Alteration Rules

A London flat owner (leaseholder) owns the right to occupy the flat for the duration of the lease — typically 99, 125, or 999 years. The freeholder owns the freehold of the building and the structure, fabric, and common parts. The lease sets out the rights and obligations of both parties. For alteration and extension works, the relevant provisions in the lease are typically: A covenant against alterations: almost all long residential leases in London contain a covenant (an obligation) by the leaseholder not to carry out alterations to the flat (particularly structural alterations) without the prior written consent of the freeholder. Clause variations: some leases distinguish between minor internal non-structural alterations (which may be permitted without consent, or subject to a simple notification requirement) and structural or external alterations (which always require formal consent). Some London leases are very restrictive — prohibiting all alterations including moving internal partition walls. Some are more permissive — prohibiting only structural or external alterations. You must read your specific lease (or ask your solicitor to review it) before starting any works. Consequence of breach: carrying out alterations to a London flat without the required leasehold consent is a breach of covenant. The freeholder can take legal action including: seeking an injunction to stop the works; requiring reinstatement of the alterations at the leaseholder's cost; and in extreme cases, forfeiture of the lease. Even if the freeholder does not act immediately, an unremedied breach of covenant will emerge in the title search when the flat is subsequently sold — making it very difficult to sell or mortgage the flat.

Where the lease requires freeholder consent for alterations, the formal document that provides that consent is typically called a licence to alter (or a licence for alterations). The licence to alter process for London flats: 1. Pre-application contact: the leaseholder contacts the freeholder (or their managing agent) in writing to request consent for the proposed works, providing a description of the works, preliminary drawings or specifications, and relevant professional appointments. 2. Freeholder review: the freeholder (usually via their managing agent and/or solicitor) reviews the application and may: request additional information (structural calculations, architect's drawings, schedule of works); require the leaseholder to obtain planning permission and/or Building Regulations approval before consent is granted; instruct a surveyor to review the proposals and carry out a pre-works condition survey of adjacent flats and common parts; or raise specific conditions that must be incorporated into the licence. 3. Licence negotiation: the leaseholder's solicitor and the freeholder's solicitor negotiate the terms of the licence to alter. Standard conditions in a London flat licence to alter: the works must be carried out by a suitable contractor; the contractor must have adequate public liability insurance; the works must comply with the Building Regulations; the leaseholder must provide the freeholder with a copy of the Building Regulations completion certificate after completion; the leaseholder must make good any damage to common parts during the works. 4. Licence execution: both parties sign the licence to alter. The leaseholder can then start the works. Cost of a licence to alter in London: the leaseholder typically pays the freeholder's surveyor fees (£1,500-£3,000), the freeholder's legal fees (£1,500-£3,000), and their own solicitor fees (£1,500-£3,000). Total licence to alter cost: £4,500-£9,000. This cost should be budgeted at the outset of any alteration project in a London flat.

The types of structural alteration most commonly sought in London flats: Removal of internal partition walls: the most common request — removing a non-structural internal partition to create an open-plan kitchen-living space. In most London flats, internal partition walls are not structural (the building structure is provided by the floors, external walls, and any structural walls at the party wall boundaries). However, whether a specific internal wall is structural must be confirmed by a structural engineer. A licence to alter for removal of a non-structural internal partition is usually granted in London, subject to standard conditions. Combining two flats: merging an upper and lower flat (typically by creating an internal staircase connecting them) is a significant structural alteration and requires both freeholder consent and planning permission (a change of use from two dwellings to one, or a material alteration requiring planning). Very complex to achieve in a leasehold context. Installation of underfloor heating: a UFH system requires lifting the existing floor construction and modifying the heating system. Impact on the structure below (heat transfer to the flat below) and building services must be assessed. Freeholder consent is typically required. Wet rooms and ensuite bathrooms: cutting the floor for drainage and modifying the plumbing affects the structure and may affect the flat below. Freeholder consent and often a waterproofing specification from a specialist are required. The Building Regulations requirements for tanking and drainage in an upper-floor wet room must be carefully followed.

The question of extending a London flat externally (creating more floor space) is highly complex. In most cases, a leaseholder does not have the right under their lease to extend the flat into common areas, the roof space, or external areas — because they own neither the freehold nor the relevant part of the building. Possible external extension scenarios for London flat owners: Roof space conversion (top-floor flat): if you own the top-floor flat and your lease grants you rights to the roof space above, a loft conversion or roof terrace may be possible. However: most London top-floor flat leases do not automatically include the roof space — the lease must be checked carefully. If the roof space is not within the demise of the flat, the leaseholder must negotiate with the freeholder to purchase or lease the roof space before a conversion can proceed. This is a negotiation and may be expensive. The freeholder may refuse to sell or lease the roof space. Ground-floor garden flat: if the lease includes the garden area, an outward extension into the garden may be possible — but again, requires freeholder consent and planning permission, and the lease must confirm that the leaseholder has sufficient rights in the garden area to build on it. Retrospective lease extension to include new space: where a leaseholder successfully agrees with the freeholder to extend into a new area (roof space, garden), the lease demise must be formally extended to include the new space. This is a legal process requiring solicitors on both sides. Practical reality for most London leaseholders: external extensions to London flats are rarely straightforward and often not achievable without significant negotiation with the freeholder. The more practical path for most London flat owners seeking more space is to move to a larger flat or purchase the freehold of a converted Victorian house (obtaining freehold removes most of these constraints).

Steps to take before starting any works in a London leasehold flat: Read your lease: the starting point is always the specific terms of your lease. Ask your solicitor to review the alteration provisions and advise on what requires consent and what the consent process involves. Contact the managing agent early: before approaching a contractor or architect, contact the freeholder's managing agent and explain what you want to do. An informal conversation (which should be followed up in writing) will quickly establish whether the freeholder is likely to be supportive and what documentation they will require. Appoint an architect: for any significant alteration (structural wall removal, bathroom addition, layout reconfiguration), appoint an architect to prepare drawings. The managing agent and freeholder will expect proper technical drawings as part of the consent application. Get a structural engineer involved: for any works that might affect the structure (floor construction, structural walls, ceiling levels), a structural engineer's assessment confirms what is and is not structural and provides the calculations required for the Building Regulations application. Budget for the licence: include the cost of the licence to alter (£4,500-£9,000) in your project budget from the outset. Allow time: the licence to alter process for a London flat alteration typically takes 2-4 months. Do not commit to a contractor start date until the licence is signed. Use qualified contractors with relevant experience: the freeholder will typically require a contractor with adequate insurance and experience of working in a London leasehold building. RCB Design & Build has extensive experience of alteration works in London leasehold flats and can manage the coordination with the freeholder's surveyor and managing agent as part of the project.