Changing windows in a leasehold flat often feels like a straightforward upgrade — better warmth, reduced noise, improved security and appearance. But in leasehold buildings, windows are frequently treated as part of the external envelope and overall appearance of the block, which means they’re commonly controlled by the freeholder/managing agent and may require a Licence for Alterations (and sometimes other approvals too).
Even when the windows sit within your flat, the freeholder’s concerns are usually the same:
- keeping the building weathertight and structurally sound
- maintaining a consistent external appearance
- ensuring compliance with fire safety and building regulations
- managing future maintenance responsibilities
- protecting other residents from disruption and defective workmanship
Below is a detailed guide to when a licence is needed, what freeholders look for, the typical procedure, common pitfalls, and how to make consent more likely.
1) Why window changes are tightly controlled in leasehold buildings
Unlike internal finishes, windows can affect more than your own flat. They are part of the building’s “skin” and often part of a planned maintenance cycle. Freeholders typically control window changes because they impact:
A) External appearance and uniformity
A block can look messy quickly if every flat installs different profiles, colours, glazing bars, or opening patterns. Most freeholders want consistent:
- frame style and thickness
- colour/finish
- glazing proportions and bars
- opening arrangement (e.g., top-hung vs side-hung; sash style)
- trickle vents and hardware style
B) Weather tightness and building integrity
Poor installation can cause:
- water ingress around frames
- deterioration of surrounding masonry
- internal condensation issues due to incorrect detailing
- long-term repair liability for the building fabric
C) Fire safety and performance
Some windows may form part of:
- fire separation strategy (e.g., proximity to boundaries)
- protected escape routes (in certain building designs)
- requirements for smoke ventilation or means of escape windows in some scenarios
D) Noise and thermal performance
While improved glazing is a benefit, a freeholder will want assurance the chosen system is appropriate and properly installed.
E) Future maintenance and ownership responsibility
Depending on the lease, the windows may be:
- part of the “demised premises” (your responsibility), or
- retained by the freeholder (their responsibility), or
- a mixed responsibility (frames vs glass, seals, etc.)
The freeholder will want clarity so maintenance obligations don’t become disputed later.
2) Do I always need a Licence for Alterations to change windows?
Not always — but you should assume yes until proven otherwise by the lease.
You are likely to need consent if:
- the lease restricts alterations affecting the exterior or “structure”
- the lease says you must not alter windows/frames without consent
- the building has a managing agent policy controlling external changes
- the new windows will change the external appearance in any way (style, colour, glazing pattern)
Even if a lease is silent, many buildings operate rules requiring consent to keep the façade consistent.
3) Other approvals often linked to window changes (important)
A Licence for Alterations is one part of compliance, but window replacements may also require:
A) Building Regulations compliance
Window replacement usually needs to meet energy performance and safety requirements. Common routes include:
- installation by an installer who can self-certify compliance, or
- approval via local authority building control
Keeping completion certification is important for future saleability.
B) Planning permission (sometimes)
Most like-for-like replacements in many areas don’t require planning, but you should be cautious if:
- the building is listed
- it’s in a conservation area
- the change alters appearance materially
- the building has planning conditions about fenestration
C) Management company or superior landlord consent
Some blocks have layered ownership/management. Consent might be needed from more than one entity.
4) What the freeholder’s surveyor will look for
When reviewing a window change proposal, surveyors typically assess:
A) “Like-for-like” vs “material change”
They want to know whether the change alters:
- frame profile and thickness
- colour
- sight lines and glazing bars
- opening arrangement
- external cills and reveals
- trickle vents and how they appear externally
Like-for-like replacements that match the original design are usually easier to approve.
B) Specification suitability
They may review:
- manufacturer and system type
- glazing specification (double/triple, safety glass where needed)
- ventilation provision (trickle vents where required)
- thermal performance (U-values)
- drainage/weeps and seals
- ironmongery and locking
C) Installation approach and detailing
This is critical. They may want:
- installation method statement
- how frames will be fixed
- how perimeter sealing will be done
- how making good of internal and external reveals will be finished
- waste removal and protection of common parts
D) Contractor competence and insurance
Freeholders often require:
- contractor details
- public liability insurance
- confirmation of certification route
5) Typical documents required for a window Licence for Alterations application
A strong application pack often includes:
- a written scope (how many windows, which elevations, what style)
- photos of existing windows
- manufacturer specification sheets and drawings
- colour samples/finish confirmation
- details of opening types and glazing pattern
- installation method statement and programme
- contractor details and insurance evidence
- confirmation of Building Regulations compliance route (and who will certify)
Some managing agents also ask for:
- a deposit against damage to common parts
- restrictions on working hours
- arrangements for scaffolding or access if required
6) Common Licence conditions for window changes
Even when approved, a licence often includes conditions such as:
- windows must match an agreed specification (and cannot be changed without approval)
- colour and profile must match the existing building scheme
- installation must be by a competent contractor with appropriate insurance
- compliance with Building Regulations must be demonstrated
- protection of common parts and making good of any damage
- working hours restrictions and nuisance control
- disposal of old frames/glass in a safe manner
- requirement to maintain windows in good order thereafter
Some licences also require that if the building adopts a future window replacement programme, you may need to align with it.
7) What commonly causes refusal or delay?
The most frequent sticking points are:
A) Appearance mismatch
- different sight lines
- different frame widths
- different colour tones
- removal/addition of glazing bars
- inconsistent opening pattern
B) Poor specification or vague proposals
- no technical details provided
- “we’ll choose later” approach
- unclear whether vents are included
- no drawings or photos
C) Certification uncertainty
- no clear Building Regulations compliance route
- contractor not appropriately qualified/certifying
D) Listed building / conservation restrictions
- lack of planning confirmation where required
- inappropriate modern profiles
E) Access, scaffolding and nuisance concerns
- no plan for safe access
- disruption to neighbours
8) How to make window consent smoother (practical tips)
- Match the existing style wherever possible (profile, colour, opening pattern)
- Provide a clear specification pack (manufacturer details, drawings, finish)
- Use a competent installer with clear certification route
- Show how you’ll protect common parts and manage waste
- Keep communications written and organised
- Don’t order windows until the freeholder confirms the spec is acceptable (to avoid costly re-orders)
The takeaway
Window changes are frequently controlled in leasehold buildings because they affect the external envelope, appearance, and long-term maintenance of the block. A Licence for Alterations is usually required, and the freeholder’s focus will be on appearance consistency, proper installation, and compliance evidence. A strong, detailed application pack is the best way to reduce delay and avoid refusal.
Planning window changes and want to get consent without delays?
Email mail@howorth.uk or call 07794 400 212. Tell us what type of building you’re in, what windows you want to replace, and whether you’re aiming for like-for-like or an upgrade. We’ll explain what freeholders typically require, what can cause refusal, and how to prepare a decision-ready submission that keeps the approval process smooth.