Replacing timber windows in a leasehold flat in London may involve the freeholder as well as a window specialist. Your lease sets out who is responsible for the windows and whether you can arrange their replacement yourself.
Written consent may be needed even if the new windows match the originals. Planning permission and Building Regulations need to be considered separately before work begins.
Who is responsible for the windows in a leasehold flat?
Your lease should set out which parts of the windows you must maintain and which are the landlord’s responsibility. Check the repair and service charge clauses, along with the description of the parts included in your lease, often called the “demised premises”. Look for any separate wording on window frames and glass. LEASE’s guidance on repairs and maintenance explains how responsibility is allocated.
Being responsible for repairs does not necessarily allow you to replace the windows without consent. Check the alteration clauses as well as the repair obligations, using GOV.UK’s leaseholder guidance as a starting point.
Where the landlord arranges repairs or replacement, you may still have to contribute through the service charge, depending on the lease.
Eligible leaseholders whose landlord is Islington Council can apply for a deed of variation to take over responsibility for future repairs, maintenance and renewal of their window frames.
Who can give permission for replacement windows?
Permission must come from the party authorised under the lease and the building’s management arrangements. Ask the freeholder or managing agent who handles window alterations and whether they can grant consent or need to refer the request elsewhere. In a building managed by a Right to Manage (RTM) company, consent for alterations may be that company’s responsibility, as LEASE explains.
Borislav Čakarević of Repair A Sash highlights a practical issue with flat projects: the freeholder may have a say in both whether replacement goes ahead and which windows can be fitted.
Depending on the lease and the proposed work, written consent may take the form of a licence to alter, a formal legal document authorising the changes. LEASE’s guidance on alterations explains the possible requirements and restrictions. If the lease is unclear or there is a disagreement about what it allows, seek advice from a solicitor or leasehold adviser.
Does like-for-like replacement still need consent?
Matching the existing design does not automatically remove any consent requirement in the lease. When requesting permission, make clear what will be retained and what will be changed.
For sash windows, this might mean repairing the existing joinery, fitting new sashes into the existing box frame or choosing a complete timber sash window replacement, including its box. Consent may still be required when the original box frame is retained.
How do planning permission and Building Regulations fit in?
Planning permission and Building Regulations do not replace any consent required by your lease. They deal with the acceptability of the proposed changes and the standards the work must meet. For flats, the Planning Portal advises that identical replacement windows should not normally need planning permission. Changes in size or appearance may require an application. Confirm the position with your local planning authority, including any need for listed building consent. Our guide to sash window changes in a conservation area or listed building covers the heritage checks.
Replacement windows normally need to comply with Building Regulations. We are registered with FENSA, a competent person scheme, and can self-certify qualifying replacement installations.
| Check | What it covers | Who to contact |
| Lease or landlord consent | Consent for the work under the lease | Freeholder or authorised management body |
| Planning permission | Acceptability of proposed changes in planning terms, if permission is needed | Local planning authority |
| Listed building consent, where applicable | Works affecting a listed building’s special architectural or historic interest | Local planning authority |
| Building Regulations | Compliance with the relevant building standards | Installer for qualifying scheme work; otherwise the appropriate building control body |
What should you prepare before requesting approval?
Ask the freeholder or managing agent what information they need to assess the proposal. A request may include:
- photographs of the existing windows;
- a description of what will be retained or replaced and the proposed appearance;
- drawings showing window dimensions and profiles, where requested;
- a quotation and the contractor’s contact details;
- contractor insurance, proposed timing and access arrangements, if requested.
For sash windows, show whether the box frame will remain and how the proposed profiles and glazing-bar layout compare with the existing window.
We can survey your timber windows, prepare a quotation describing the proposed work and provide window drawings for you to submit with an application.
What should be agreed before the windows are ordered?
Before placing an order, obtain any required written permissions and make sure the final window specification matches what has been approved. Agree who will commission the work, the installation arrangements and any conditions affecting access to shared areas or the use of scaffolding. Ask how Building Regulations compliance will be recorded and which documents you will receive on completion.
Also ask whether a block-wide window programme affects your plans. If the landlord is arranging replacement for the building, establish whether an individual project can proceed before ordering separately.
Keep copies of the consents and the installation’s completion documents. A buyer’s solicitor may ask for them when you sell.
Contact Repair A Sash to discuss your timber windows and arrange a survey. We can assess the existing joinery and prepare a quotation for the proposed work.
Frequently asked questions about leasehold window replacement
No. A share of freehold does not remove the obligation to follow the lease, including any alteration conditions. Check who is authorised to decide requests and obtain written consent if the lease requires it.
Yes. A survey and quotation can help you prepare a proposal for approval. Obtain any required permissions before placing an order for manufacture or installation.
No. A FENSA certificate confirms Building Regulations compliance for eligible work. Any required freeholder consent or planning permission must be obtained separately.
Reviewed by and sources
Technical review: Borislav Čakarević, Repair A Sash
Independent references
- GOV.UK, Leaseholder rights and responsibilities
- LEASE, Repairs and maintenance in leasehold properties
- LEASE, Alterations and home improvements
- LEASE, Granting approvals (Right to Manage)
- LEASE, Buying and selling: an introduction
- Planning Portal, Change windows of a flat
- GOV.UK, Use a competent person scheme
- FENSA, Information for homeowners and certificate coverage
- Islington Council, Taking ownership of your windows
