Renovating a flat in the UK isn’t the same as renovating a house. The lease, the freeholder, and building regulations all have a say in what you can do. A cosmetic refresh on a one-bedroom flat typically costs between £5,000 and £15,000, while a full gut and reconfigure can run £40,000 to £80,000 or more. In London, add 20–35% on top of those figures.
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This article is general information only and does not constitute professional advice. For your specific situation, consult a qualified professional.
Most flats in the UK are leasehold. You own the internal space, but the building structure, walls, floors, and communal areas belong to the freeholder. That distinction matters more than most buyers realise. It determines what you can change, who you need to ask, and how long the whole process takes. If you’re looking at a flat and wondering about renovation potential, the leasehold restrictions and warning signs are worth understanding before you commit. Here’s what you actually need to know.
The central concept you’ll run into is the Licence to Alter. This is formal written permission from the freeholder or managing agent allowing you to carry out specific works. It’s a legal document, not a casual email. Most leases require one before any structural, service, or significant cosmetic work begins. Without it, you’re in breach of your lease.
What I tend to notice is that people focus on the renovation cost and forget the permission cost — both in fees and time. A Licence to Alter can take weeks to process and may set you back £500–£2,000 before any work starts. That’s separate from the building control fees and the contractor’s invoice.
What a Flat Renovation Actually Costs in 2026
The headline figures are one thing. The full picture includes fees you might not expect. Here’s how the costs break down for a typical one-bedroom flat (40–55m²) outside London, based on current market data.
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| Renovation type | Cost range (1-bed) | Typical timeline | Key permissions needed |
|---|---|---|---|
| Cosmetic refresh | £5,000–£15,000 | 6–10 weeks | None typically, but notify managing agent |
| Kitchen or bathroom upgrade (same layout) | £8,000–£20,000 | 8–12 weeks | Licence to Alter if plumbing or drainage changes |
| Full renovation (new layout, non-structural) | £20,000–£50,000 | 10–14 weeks | Licence to Alter + building regs for electrical/plumbing |
| Full gut and reconfigure (structural changes) | £40,000–£80,000 | 12–18+ weeks | Licence to Alter + building regs + structural engineer |
In London, add 20–35% across all categories. A two-bedroom flat (60–80m²) scales up roughly 30–40% from these figures. The costs aren’t just about materials and labour. Access restrictions in apartment blocks mean materials often have to be carried through shared areas and up stairwells, which adds time and labour charges. Working hours are typically limited to 8am–6pm on weekdays, with no weekend or bank holiday work allowed in most residential blocks.
If you’re planning a renovation and need clarity on your lease obligations, a property lawyer can review your lease and tell you exactly what permissions you need before you spend a penny on contractors.
Common Mistakes That Cost Flat Owners Time and Money
Starting work before getting the Licence to Alter
This is the most expensive mistake I see. The lease almost certainly requires written consent for anything beyond decoration. If you start work without it, the freeholder can demand you stop, reinstate the property at your cost, and charge legal fees. When you come to sell, your buyer’s solicitor will spot the missing consent. The sale can fall through, or you’ll have to apply for retrospective consent — which the freeholder can refuse or charge a premium for. The process for getting a Licence to Alter involves submitting detailed plans, a description of the works, proof of contractor insurance, and often a fee. Allow 4–8 weeks for processing.
Assuming your lease allows what you want to do
Some leases contain an “absolute covenant” against alterations — meaning no changes at all, even cosmetic ones. Others have a “qualified covenant” where consent cannot be unreasonably withheld. A few older leases are silent on alterations, which doesn’t automatically permit them. You need to read the actual lease clauses on alterations, reinstatement, flooring restrictions, and shared services like soil stacks and communal heating. If the lease bars alterations, you may need to negotiate a formal variation — an expensive and time-consuming process. A leasehold solicitor can interpret the covenant before you make plans.
Ignoring building regulations because it’s a flat
Building regulations apply to flats exactly as they do to houses. Structural alterations, electrical rewiring, new bathrooms, drainage changes, boiler installations, and window replacements all need approval. The leaseholder pays for building control — application fees and inspection costs — separate from the Licence to Alter. You can use your local authority building control or a private registered building control approver. For electrical work, a registered electrician can self-certify under a competent person scheme. For structural work, you’ll need a structural engineer’s calculations and a building notice or full plans submission. Non-compliance can lead to enforcement notices, fines, and problems selling the property.
Underestimating the access and neighbour situation
Apartment blocks impose rules that house owners don’t deal with. Working hours, lift usage, material delivery windows, protection of communal areas, and noise restrictions are all specified in the building’s terms. Ignoring them leads to complaints from neighbours, disputes with the managing agent, and potentially a halt to your project. Before work starts, notify the managing agent in writing, agree the access arrangements, and confirm the working hours. If your work affects the flat below — through noise, vibration, or drainage changes — you may need to coordinate with that leaseholder too.
How to Renovate a Leasehold Flat Without Legal Trouble
Step one: read your lease and identify the covenant
The lease is the starting point. Look for clauses headed “Alterations,” “Improvements,” or “Consent.” Identify whether the covenant is absolute (no alterations permitted) or qualified (consent cannot be unreasonably withheld). Also check for restrictions on flooring — many leases ban hard flooring in upstairs flats due to noise transmission. If the lease is unclear, ask a solicitor before proceeding. The Leasehold Advisory Service (LEASE) offers free initial guidance on lease terms.
Step two: apply for a Licence to Alter
Submit a written application to the freeholder or managing agent. Include detailed plans or drawings, a description of the works, the contractor’s details and insurance, and a proposed timeline. The freeholder can charge reasonable legal and administrative fees — ask for an estimate upfront. If the freeholder refuses consent, ask for written reasons. If you believe consent is being unreasonably withheld, you can apply to the First-tier Tribunal (Property Chamber) for a decision. The tribunal can impose conditions and may allow the work to proceed.
Step three: secure building regulations approval
For structural work, electrical rewiring, drainage changes, new heating systems, or window replacements, submit a building notice or full plans to your local authority building control or a registered building inspector. For smaller jobs, a competent person scheme installer can self-certify. Keep all certificates — completion certificates, electrical installation certificates, and boiler commissioning records — in a file with the approved plans. You’ll need them when you sell.
Step four: manage the build with leasehold constraints in mind
Book the lift, agree delivery times, protect communal areas with dust sheets and floor protection, and stick to the permitted working hours. If your lease requires it, arrange for a pre-work inspection with the managing agent. After completion, some freeholders require a post-work inspection and a certificate of compliance. Keep dated copies of all correspondence, photos of the property before and after works, receipts for materials, and contractor invoices.
What’s changing in 2026 that affects flat renovations
The Future Homes Standard brings stricter fabric efficiency requirements and effectively bans gas boilers in new builds — heat pumps or heat networks will be the norm. For existing flats, the Building Safety Act 2022 imposes tighter oversight on higher-risk residential buildings, including a three-gateway approval process and a “golden thread” of documented information. The Renters’ Rights Act abolishes Section 21 evictions for periodic tenancies by 31 May 2026, which affects landlords renovating between tenancies. EPC C becomes the minimum standard for rental properties by 2030, so any renovation now should factor in insulation and heating upgrades. Ground rents are being capped, and commonhold is set to replace leasehold for new flats — but existing leaseholders will still operate under current rules for the foreseeable future.
If you’re renovating a flat you plan to rent out, the service charge implications and leasehold costs are worth reviewing alongside your renovation budget.
Frequently Asked Questions
Do I always need freeholder consent to renovate a leasehold flat? ▾
What happens if I renovate without a Licence to Alter? ▾
Can my freeholder charge me for giving consent? ▾
Do I need planning permission for internal flat renovations? ▾
Can a tenant renovate a rented flat? ▾
How long does a Licence to Alter take to get? ▾
The Bottom Line on Flat Renovations in 2026 and Beyond
The regulatory landscape for flat renovations is tightening. The Building Safety Act, the Future Homes Standard, and the shift toward commonhold all point in one direction: more documentation, higher standards, and less tolerance for non-compliance. A well-planned, properly consented renovation adds genuine value. A rushed one creates legal and financial problems that can last for years. The difference comes down to reading the lease first, getting the Licence to Alter in place, and treating building regulations as a requirement rather than an afterthought.
Remember: this article is general information only. For advice on your specific situation, speak to a qualified professional.
If this was useful, you might also want to read The Apartment Hunting Checklist: Don’t Miss These Essential UK Points.
Sources and Further Reading
Top Considerations When Buying an Apartment in the UK — A broader look at what to check before buying a flat, including lease terms, service charges, and renovation potential.
Shared Ownership Apartments: A UK First-Time Buyer’s Route to Ownership — How shared ownership affects your ability to renovate and what permissions you need.
LDN Renovation (2026). Renovating a London Flat — What You Can and Can’t Do. 🔗
Housey (2025). Leasehold Flat Renovation Permissions, Planning & Building Regulations. 🔗
RenoCalc (2026). Flat Renovation Cost UK. 🔗
Material Essentials (2026). UK Building Regulations Changes 2026. 🔗
Tenant Rights UK (2025). Tenant Alterations: Consent Rules in England. 🔗
