Renovating a Leasehold Flat in London: What Your Lease Actually Permits

The majority of London's flat stock is leasehold — held on long leases (typically 99–999 years) from a freeholder. The leasehold structure means you own the right to occupy the property for the lease term, not the building itself. This distinction has significant practical consequences for renovation: many works that a freeholder can carry out freely require formal consent from the freeholder (or their managing agent) before they can lawfully proceed.

Carrying out works without required consent is a breach of the lease — potentially a serious one. It can result in enforcement action, difficulty at sale, and invalidation of buildings insurance. Understanding what your lease requires before beginning a renovation is essential.

Read the lease (or have your solicitor read it)

The starting point is the lease itself. Key clauses to review:

Alterations clause: Most leases contain an absolute or qualified covenant against alterations. An *absolute* covenant prohibits alterations entirely — in practice, this is rare in modern leases. A *qualified* covenant prohibits alterations without landlord consent, which must not be unreasonably withheld. The specific wording matters. Common formulations:

• —"Not to make any structural alterations without the consent of the Landlord" — structural works need consent
• —"Not to make any alterations or additions without the Landlord's prior written consent" — all alterations need consent, not just structural
• —"Not to do or permit to be done any act or thing which may become a nuisance or annoyance to the Landlord or other tenants" — a catch-all that can be invoked even without a specific alterations clause

Floor covering clause: Very common in apartment buildings. Typically requires that all floor areas (or a specified proportion, often 80%) are covered with carpet or similar soft floor covering to reduce impact noise transmission to the flat below. This directly restricts the installation of timber, stone, or tile flooring throughout the flat. If you want hard flooring throughout, you will need the freeholder's consent — and will likely need to demonstrate that acoustic underlay is provided to achieve a specified impact sound rating.

Consent requirements: Many leases require consent for plumbing alterations, alterations to the electrical system, changes to the kitchen or bathroom location, and any penetration of the building structure.

The consent process

Where consent is required, the process is:

1. 1.Write to the freeholder (or their managing agent) setting out the proposed works in sufficient detail — drawings, specifications, and a statement of how the works will affect the building and other leaseholders.
2. 2.The freeholder responds within a reasonable time (typically 28–42 days) with consent (possibly conditional), refusal (which must be on reasonable grounds if the covenant is qualified), or a request for further information.
3. 3.Consent may be conditional — requiring specific contractors, specific materials, acoustic survey after completion, or reinstatement at the end of the lease.
4. 4.The freeholder will typically charge a licence fee (often £500–£2,000) and will require the leaseholder to meet their legal costs in reviewing and documenting the consent.

Consent must be obtained *before* works begin, not retrospectively. Retrospective licence applications are often refused and even where granted, the leaseholder remains in breach for the period during which works were carried out without consent.

Structural works

Any alteration that affects the structure of the building — including the slab, the external walls, the roof structure, or load-bearing internal walls — almost certainly requires freeholder consent regardless of what the lease says about alterations, because the structure typically belongs to the freeholder even within the demise of the flat.

Internal non-structural walls within the demised area may be removable without consent under some leases, but confirm before proceeding.

Sublet and mortgagee considerations

If the flat is mortgaged, the mortgage lender may also require notification or consent for major alterations. Lenders typically have a standard requirement that the security property is not materially altered without their knowledge. Check your mortgage conditions.

If the flat is sublet, the subletting agreement does not pass on the right to carry out alterations — any works must be authorised by you as leaseholder with the freeholder's consent, regardless of whether a tenant is in occupation.

Estate-managed properties

Leasehold properties on managed estates — the Grosvenor Estate in Belgravia and Mayfair, the Cadogan Estate in Chelsea, the Howard de Walden Estate in Marylebone — operate with an additional layer of estate management standards. The estate managing agent will review proposed works for compliance with estate design standards as well as lease requirements. These standards often specify materials, finishes, and contractor requirements in detail.

For works on an estate-managed property, budget for an extended consent process (6–12 weeks is common), specialist contractor requirements (some estates maintain approved contractor lists), and more detailed documentation requirements than a standard freeholder would impose.

Practical guidance

Before instructing an architect or contractor:

1. 1.Obtain and read your lease — specifically the alterations, floor covering, and user clauses
2. 2.Identify which of your proposed works require consent
3. 3.Instruct your solicitor to confirm your reading of the lease and advise on the consent process
4. 4.Make the consent application with professional drawings and specifications — freeholders respond better to well-prepared applications
5. 5.Do not begin any works until written consent is in hand

ASAAN regularly works within leasehold renovation constraints, preparing consent applications, coordinating with estate management teams, and delivering works that comply with lease and estate requirements. If you are planning a leasehold flat renovation, contact us early — the consent timeline should be factored into the overall project programme.