If you’re taking on new business premises, the chances are the space will not be perfectly suited to your needs on day one. Most commercial tenants want to make changes — whether that’s installing partition walls, rewiring for data cabling, or undertaking a full commercial fit-out to transform a shell unit into a functional workspace. The question is: can you simply go ahead and make those changes?
The short answer is almost certainly not without permission. Commercial property alterations are one of the most tightly regulated areas of commercial leasing in England and Wales, and getting it wrong can expose you to serious legal and financial consequences — including a claim for breach of lease.
This guide explains what commercial property alterations you can and cannot make, what legal consents you need to obtain, how a licence to alter works, and what practical steps will protect your position both during the works and at the end of your lease.
Start by reading your lease
Before you commission an architect or call a contractor, your first task is reviewing your lease carefully. The lease is the governing document that determines what you are and are not permitted to do with the premises. Every commercial lease treats alterations differently, and the detail varies significantly from one agreement to the next.
Most commercial leases follow a tiered structure when it comes to alterations:
- Structural alterations – typically prohibited outright or subject to the landlord’s absolute discretion
- Non-structural alterations – often permitted but only with the landlord’s prior written consent
- Minor or cosmetic works – sometimes permitted without any formal consent requirement, though this is increasingly rare
Even where a lease appears to permit non-structural works, the clause will frequently contain conditions: works must be carried out to a professional standard, by qualified contractors, in compliance with all statutory requirements, and often within a defined timeframe. Overlooking any of these conditions can place you in breach, even if the landlord has given consent to the works themselves.
If you are at the stage of negotiating a new lease rather than already bound by one, this is the right moment to negotiate alterations into your lease terms upfront. Agreeing a schedule of permitted works or pre-approving specific fit-out items as part of the initial transaction is considerably simpler — and cheaper — than seeking a separate licence after the lease has completed.
What is a licence to alter?
A licence to alter — sometimes called a licence for works or a licence for alterations — is a formal legal document supplemental to the lease that records the landlord’s written consent for specific works. It sits alongside the lease rather than replacing or amending it, and it sets out the agreed scope of works, the conditions under which they must be carried out, and the parties’ respective obligations once the works are complete.
A licence to alter is not optional paperwork. Where the lease requires landlord consent for alterations, proceeding without a formal licence in place constitutes a breach of lease — regardless of whether the landlord appears to have verbally agreed to the works. Without a signed licence, there is no enforceable record of what was approved, and disputes at the end of the lease become significantly harder to resolve.
The licence will typically address:
- Scope of the works: A precise description of what is being permitted, usually with detailed drawings and specifications annexed
- Standards and compliance: Requirements to carry out works to a professional standard, in accordance with building regulations and all relevant statutory consents
- Insurance: Obligations on the tenant to maintain adequate contractor insurance throughout the works
- Completion deadline: A longstop date by which works must be finished, after which the landlord’s consent may lapse
- Post-completion obligations: Requirements to notify the landlord on completion and provide updated plans, an updated EPC where relevant, and copies of any statutory approvals
- Reinstatement: Whether the tenant will be required to remove the alterations and reinstate the property at the end of the lease
In some cases, third-party consent will also be required — for example, from a superior landlord, a mortgagee with an interest in the property, or a neighbouring owner under the Party Wall etc. Act 1996. These additional parties may need to be made party to the licence, which can extend the timeline for obtaining consent.
Types of commercial property alterations and what each requires
Structural alterations
Structural alterations involve changes to the fabric of the building: removing or replacing load-bearing walls, altering the foundations or roof, adding mezzanine floors, or making external modifications. In most commercial leases, structural alterations are either absolutely prohibited or require the landlord’s express consent, which the landlord is not obliged to grant.
Where structural works are permitted at all, they will almost certainly require planning permission (particularly where the external appearance of the building is affected), full building regulations approval, and in some cases compliance with the Party Wall etc. Act 1996. For higher-risk buildings, additional obligations may arise under the Building Safety Act 2022 and the Construction (Design and Management) Regulations 2015.
The practical reality is that most landlords are reluctant to approve structural alterations because of the potential impact on the building’s structural integrity, its capital value, and its insurability. If you anticipate needing structural works, this should be discussed and agreed — in principle at least — before you commit to taking the lease.
Non-structural alterations and fit-out works
Non-structural alterations are changes to the interior of the premises that do not affect the building’s structure. This is the category that covers the majority of commercial fit-out activity: installing partition walls, laying new flooring, upgrading electrical wiring and data infrastructure, fitting air-conditioning or ventilation systems, installing specialist trade equipment, and applying signage and branded finishes.
This type of commercial fit-out will almost always require the landlord’s prior written consent and a licence to alter, even where the lease appears broadly permissive. Landlords typically want to review detailed plans before granting consent and may instruct their own building surveyor to assess the proposals, the cost of which is usually passed to the tenant.
Although planning permission is rarely required for purely internal works with no external effect, building regulations approval is commonly needed — particularly for changes to fire safety systems, means of escape, electrical installations, and mechanical ventilation. The tenant is responsible for obtaining and complying with all such consents.
Minor and cosmetic works
Some leases permit a narrow category of minor works — decoration, the installation of non-fixed shelving, minor IT cabling — without requiring formal consent. However, what qualifies as ‘minor’ is a matter of interpretation, and tenants should not assume that works fall into this category without checking the specific wording of the lease. A decoration clause that appears broad may still restrict colour changes or require works to be carried out in neutral shades at lease end.
Statutory consents you may need beyond the lease
Obtaining the landlord’s consent under the lease is only one piece of the puzzle. Depending on the nature and extent of the proposed works, you may also need to obtain one or more statutory consents before starting.
- Planning permission: Required for external alterations that affect the building’s appearance, changes to the building’s use class (for example, converting office space to retail), or any development that goes beyond permitted development rights. You can check what requires permission through the Planning Portal.
- Building regulations approval: Required for the majority of building work that affects structural elements, fire safety, energy performance, drainage, or means of escape. Approval is obtained from the local authority building control department or an approved inspector.
- Listed building consent: Essential if the property is a listed building. Any alteration — including purely internal works that would not require consent in an unlisted building — may require listed building consent, and works carried out without it are a criminal offence.
- Party Wall etc. Act 1996: If the proposed works affect a shared wall, party floor or ceiling, or foundations within three or six metres of a neighbouring structure, notice obligations under the Act will apply.
The lease will almost always place the responsibility for obtaining these consents on the tenant. Failure to comply is typically a breach of both the lease and the relevant statute, with potentially serious consequences including enforcement action, injunctions to stop the works, or criminal liability.
Need landlord consent for commercial property alterations?
A licence to alter records exactly what works are approved, how they must be carried out, and whether you need to reinstate them at the end of the lease. Speak to a commercial lease solicitor before starting your fit-out or responding to a landlord’s refusal.
The process of obtaining landlord’s consent
Obtaining consent for commercial property alterations takes time, particularly where the proposed works are significant. Beginning the process early is essential.
The typical process runs as follows:
- Produce detailed plans, drawings and specifications describing the proposed works, prepared by a suitably qualified architect or surveyor
- Submit a formal written application to the landlord, attaching the plans and any supporting documents such as contractor details and evidence of insurance
- The landlord reviews the application, usually with the assistance of their own building surveyor or solicitor, whose reasonable fees the tenant will ordinarily be expected to pay
- If the landlord’s property is mortgaged, their lender may also need to approve the works — adding time and potentially additional information requirements to the process
- Once the landlord is satisfied, solicitors for both parties will negotiate and finalise the licence to alter
- The licence is signed by all parties before any works commence
Importantly, where the lease states that landlord consent must not be unreasonably withheld or delayed, the landlord is legally required under the Landlord and Tenant Act 1988 to respond within a reasonable time and to give reasons for any refusal. A landlord who refuses consent arbitrarily or delays unreasonably may be liable in damages. If you encounter difficulties securing consent, our team can assist through our landlord and tenant disputes service.
Reinstatement obligations – a critical consideration
One of the most commonly overlooked aspects of commercial property alterations is the obligation to reinstate. Most leases require the tenant to remove any alterations carried out during the term and return the property to its original condition at lease end, unless the landlord agrees otherwise. This obligation can be both time-consuming and costly.
A reinstatement obligation means that a full commercial fit-out — partitions, cabling, flooring, air-conditioning systems — may all need to be stripped out and the property returned to its shell state when you vacate. In a large premises, the cost of doing so can run to tens of thousands of pounds.
There are two key points to address in relation to reinstatement:
- Negotiate at the outset: Some landlords will agree to waive reinstatement obligations for certain improvements that add value to the property, such as upgraded mechanical and electrical systems or high-specification flooring. This is most effectively negotiated at the time of the lease or when the licence to alter is agreed — not at the end of the term.
- Ensure the lease and licence are consistent: The reinstatement provisions in the licence to alter must work harmoniously with the equivalent provisions in the lease. If they conflict, uncertainty and disputes can arise at the end of the term.
If you reach the end of your lease and face a dilapidations claim that includes reinstatement of alterations, obtaining early legal advice is important. The scope of any reinstatement obligation will depend on the precise wording of both the lease and the licence.
Rent reviews and the impact of alterations
Many tenants are unaware that improvements they carry out at their own cost could, if not properly addressed, be taken into account at rent review — effectively increasing the rent in respect of improvements the tenant themselves paid for.
A well-drafted lease will contain a provision disregarding the tenant’s own improvements when assessing the open market rent at review. If your lease does not contain such a disregard, or if the wording is ambiguous, you may find that the rental value of the premises — as enhanced by your fit-out — is used as the baseline for the reviewed rent.
This issue is best addressed at the lease drafting stage. If you are already within the term of a lease and have carried out improvements, the position at rent review will depend on the specific terms agreed. In either case, taking advice before the review process begins is strongly recommended.
What happens if alterations were carried out without consent?
If works have already been carried out without the landlord’s prior written consent, the position is more complicated — but not necessarily irretrievable. Where both parties accept that the works were carried out and are content with the result, a retrospective licence can be granted, formalising the landlord’s consent after the fact. This regularises the position and protects both parties going forward.
However, if the landlord is unwilling to grant retrospective consent, the tenant is in breach of the lease. The landlord may have the right to require reinstatement of the property at the tenant’s cost, and in serious cases the breach may give rise to forfeiture proceedings. Acting promptly and seeking legal advice as soon as the issue is identified is essential.
Practical tips for a smooth commercial fit-out
Drawing together the key points from this guide, here are the most important practical steps for tenants planning commercial property alterations or a fit-out:
- Read your lease before anything else — Understand what is and is not permitted, what consent process applies, and what reinstatement obligations you will be taking on
- Negotiate at the outset — If you have not yet signed your lease, agree permitted alterations, fit-out specifications, reinstatement waivers, and rent review disregards upfront rather than dealing with them later
- Engage professionals early — Appoint a qualified architect or building surveyor to prepare detailed plans before approaching the landlord for consent; poor-quality submissions slow the process and create ambiguity
- Budget for landlord’s costs — The tenant typically bears the landlord’s reasonable legal and surveying fees for reviewing the application and preparing the licence; factor this into your project budget
- Obtain all statutory consents — Planning permission, building regulations approval, listed building consent, and any Party Wall notices must all be obtained before works begin, not after
- Ensure the licence is signed before work starts — Starting works before the licence is executed, even where heads of terms have been agreed, leaves you without the protection of formal consent
- Keep good records — Retain all drawings, the signed licence, contractor sign-off documents, building regulations completion certificates, and any correspondence about the works throughout the term of the lease
How we can help
Commercial property alterations and fit-out involve multiple overlapping legal obligations — under the lease, under statute, and potentially under third-party consents. Getting the process right from the start protects your business from costly disputes both during the tenancy and at its end. Whether you need help understanding the alteration provisions in your commercial lease, negotiating a licence to alter, or dealing with a dispute that has arisen over works already carried out, our commercial lease solicitors provide clear and practical advice at every stage.
To discuss your situation in confidence, contact Lease Lawyer on 0161 249 5087 or send an enquiry through our website.
Planning alterations or a fit-out?
Before starting work, check whether your lease requires landlord consent, a licence to alter, statutory approvals, and clear reinstatement terms. Getting this wrong can put you in breach of lease and lead to costly disputes.