Do I need planning permission for a home extension in the UK?

Many home extensions in England qualify as permitted development (PD) — meaning no planning permission is required — provided they meet specific size limits. For single-storey rear extensions, the limit is 4 metres for detached houses and 3 metres for other house types without prior approval, or up to 8 metres (detached) and 6 metres (other) under the Neighbour Consultation Scheme with prior approval notification. Extensions must not exceed 4 metres in height, must not cover more than half the garden, and must not be forward of the principal elevation (front of the house). Two-storey extensions are more restricted and generally need planning permission if they extend beyond the rear wall by more than 3 metres. Side extensions generally require planning permission. Always check with your local planning authority before committing to a project. Building Regulations approval is always required for extensions, covering structural, fire safety, insulation, and drainage compliance.

Which home improvements add the most value to a UK property?

Based on data from Nationwide Building Society, Halifax, and the HomeOwners Alliance, the UK home improvements that add the most value are: loft conversions (adds approximately 15–20% of property value, typical ROI 50–80% of cost), kitchen renovations (adds 5–10%, ROI 30–60%), bathroom renovations (adds 3–5%, ROI 20–50%), single storey extensions (adds 10–15%, ROI 40–70%), double storey extensions (adds 15–20%, ROI 50–80%), and new central heating/boiler (adds 3–7%, ROI very high when old system is replaced). Improvements that rarely recoup their full cost include swimming pools (often reduces buyer pool), very personalised decor, very high-spec finishes beyond local market expectations, and conservatories (market has softened due to thermal performance concerns). Always research your specific local property market before investing heavily.

How should I structure contracts and payments for home improvement work?

For any home improvement project over £1,000, always use a written contract. Include: full specification of works (materials, finishes, dimensions), start and completion dates, payment schedule tied to completion milestones (not time), how variations/extras will be priced and authorised, contractor's insurance details (Public Liability minimum £2m, Employer's Liability if they have employees), and dispute resolution process. Payment schedule best practice: pay no more than 10–25% upfront for materials, then further staged payments upon completion of agreed milestones, final 10% retained until practical completion and any snagging items resolved. Never pay the full balance before work is complete. For larger projects, consider using the FMB (Federation of Master Builders) Building Contract or the JCT Minor Works Contract. Disputes can be referred to the Ombudsman Services, TrustMark, or relevant trade body.

Home Improvement Cost Calculator UK 2025

Q: How much does a kitchen renovation cost in the UK in 2025?

A UK kitchen renovation costs between £8,000 and £25,000 in 2025 depending on size, quality level, and region. A basic flat-pack kitchen with standard appliances and straightforward fitting starts from around £8,000–£12,000 for a medium-sized kitchen. A mid-range renovation with new units, worktops, appliances, tiling, and electrical updates typically costs £12,000–£18,000. A luxury high-end kitchen with bespoke cabinetry, premium appliances (AEG, Miele, Bosch), quartz worktops, and designer features can reach £20,000–£35,000 or more. London and the South East typically add 20–30% to these costs. The largest cost components are usually units and appliances (40–50%), labour (30–35%), and worktops and flooring (15–20%). Kitchen renovations typically add 5–10% to a property's value according to Nationwide research.

Q: How much does a loft conversion cost in the UK?

Loft conversion costs in the UK range from £30,000 to £70,000 depending on the type and specification. A Velux (rooflight) conversion — the most affordable type — typically costs £20,000–£35,000, adding skylights without changing the roof structure. A dormer conversion (adding a box-shaped extension to the roof) costs £35,000–£55,000 and provides significantly more headroom and floor space. A hip-to-gable conversion (changing the sloping side of a hip roof to a vertical gable) costs £40,000–£65,000. A mansard conversion (altering both sides of the roof to create a near-vertical slope) costs £45,000–£70,000 and is most common in London terraces. Most loft conversions add approximately 15–20% to property value (Nationwide/Halifax data), making them among the highest-ROI home improvements available in the UK.

Q: How much does a single storey extension cost per square metre in the UK?

Single storey extension costs in the UK typically range from £1,500 to £2,500 per square metre in 2025 for a standard build. A 20m² kitchen extension would therefore cost approximately £30,000–£50,000 in most of England, including groundworks, structural steelwork, brickwork to match existing, roof, windows, glazed doors, insulation, underfloor heating, and internal decoration. London and South East costs are typically 20–30% higher, so expect £36,000–£65,000 for the same size extension in those regions. Premium specifications with bifold doors, lantern rooflight, underfloor heating, and high-spec finishes push costs to the upper end. Always obtain at least three written quotes from contractors who can show recent references and appropriate insurance (Public Liability minimum £2 million).

Q: How do I find a reliable tradesperson in the UK?

Several reputable platforms exist for finding vetted UK tradespeople. Which? Trusted Traders (trustedtraders.which.co.uk) conducts background checks, in-person assessments, and reviews — the most rigorous vetting process. Checkatrade (checkatrade.com) verifies qualifications and has genuine customer reviews. MyBuilder (mybuilder.com) allows you to post a job and receive quotes from local tradespeople, with public feedback profiles. Rated People (ratedpeople.com) is similar. For specific trades, look for regulatory body members: GAS SAFE Register for gas engineers (legally mandatory), NICEIC or NAPIT for electricians (required for Building Regulations self-certification), CIPHE for plumbers, FMB (Federation of Master Builders) for general builders. Always get a minimum of three quotes in writing, check references personally, never pay more than 25% upfront, and use written contracts specifying payment milestones. Avoid cash-in-hand deals with no paper trail.

Q: What VAT rate applies to home improvement work?

Most home improvement and building work in the UK is subject to the standard 20% VAT rate. However, there are important exceptions: energy-saving materials (insulation, heat pumps, solar panels, draught-proofing) installed in residential properties benefit from 0% VAT since February 2024. Work on properties that have been empty for two or more years is subject to 5% reduced VAT rate. Disabled facilities adaptations (ramps, stairlifts, wet rooms) are also zero-rated. New residential builds are zero-rated for VAT. If you are having energy-saving work done alongside general renovation, ask your contractor to separate the VAT calculations carefully. All VAT-registered contractors must provide a VAT invoice showing their VAT registration number, the applicable rate, and the VAT amount charged. If a contractor offers to reduce costs by not showing VAT, this is VAT fraud and should be reported to HMRC.

Last updated: February 2026

Home Improvement Cost Estimator

Project Type

Quality Level

Region

Project Size (m²) — for extensions

UK Home Improvement Costs 2025 — Quick Reference

Project	Standard	Premium	Typical Duration	Planning Needed?
Kitchen renovation	£8,000–£14,000	£18,000–£35,000	2–4 weeks	No
Bathroom renovation	£5,000–£9,000	£10,000–£20,000	1–2 weeks	No
Loft conversion (dormer)	£35,000–£45,000	£50,000–£70,000	6–10 weeks	Often PD
Single storey extension	£25,000–£40,000	£42,000–£65,000	8–16 weeks	Often PD
Double storey extension	£40,000–£65,000	£70,000–£110,000	12–20 weeks	Usually yes
Conservatory	£5,000–£15,000	£18,000–£35,000	3–6 weeks	Often PD
New boiler (gas combi)	£1,500–£2,500	£2,800–£4,500	1–2 days	No
New roof (3-bed semi)	£5,000–£9,000	£10,000–£16,000	1–2 weeks	No
Full rewire (3-bed house)	£3,000–£4,500	£5,000–£7,000	3–7 days	No
Garden landscaping	£2,000–£8,000	£10,000–£25,000	1–4 weeks	Rarely
New driveway (tarmac/block)	£2,000–£4,500	£5,000–£10,000	2–5 days	Sometimes

PD = Permitted Development. London and South East add 20–30%. All prices include VAT at 20% (energy saving items at 0%).

UK Home Improvement Guide 2025

Planning Permission vs Permitted Development

Understanding the difference between planning permission and permitted development rights is essential before starting any significant home improvement project. Permitted development (PD) rights allow many common home improvements to be carried out without formal planning permission, subject to specific limits set out in the Town and Country Planning (General Permitted Development) (England) Order 2015. Key permitted development rights for houses include: rear extensions (up to 4m for detached, 3m for other houses without prior approval notification), loft conversions adding up to 50m³ (detached/semi) or 40m³ (terraced) of space, porches up to 3m², outbuildings up to 50% of garden space. Always verify your PD rights have not been removed via an Article 4 Direction in your area — particularly common in Conservation Areas. Note that PD rights are for dwellings — flats and maisonettes do not benefit from the same PD rights.

Building Regulations: Always Required

Even when no planning permission is required, Building Regulations approval is almost always necessary for structural work, extensions, loft conversions, new electrical circuits, boiler replacements, and bathroom installations. Building Regulations ensure work meets minimum standards for structural integrity, fire safety, thermal insulation, drainage, accessibility, and energy efficiency. There are two routes to compliance: Full Plans application (submit drawings for approval before starting, recommended for larger projects) and Building Notice (notify the council and they inspect as work proceeds, faster but riskier). Some work is self-certifiable by registered competent persons: gas engineers (GAS SAFE), electricians (NICEIC/NAPIT), and plumbers (CIPHE/WIAPS) can certify their own work without a separate Building Control application. Keep all completion certificates safely — they are required when you sell the property.

Financing Home Improvements

Several financing options are available for UK homeowners funding renovation projects. Remortgaging or further advance: if your property has increased in value, borrowing against equity at mortgage rates (currently 4–5% fixed) is typically the cheapest option for large projects. Secured homeowner loan (second charge mortgage): suitable if you cannot remortgage but have equity; rates typically 6–10%. Personal loan: for projects under £25,000, unsecured personal loans from high street banks offer rates of 6–15% over 1–7 years. HELOC (home equity line of credit): not widely available in UK unlike USA, but some specialist lenders offer flexible revolving equity facilities. 0% purchase credit cards: useful for purchasing materials and appliances if you can pay off within the introductory period (typically 12–24 months). Green home improvement loans: some lenders (Ecology Building Society, Triodos) offer preferential rates for energy-efficient improvements. Always calculate the total cost of borrowing, not just the monthly payment.

Finding and Vetting Tradespeople

The UK construction sector unfortunately has a significant proportion of rogue traders and poor-quality contractors. Protect yourself by following these steps. First, always obtain a minimum of three written, itemised quotes for any project over £2,000 — this not only reveals the market rate but also helps you identify outlier quotes (very cheap quotes are often as concerning as very expensive ones). Second, check that any contractor you use is registered with the relevant trade body: Gas Safe Register for gas work (check at gassaferegister.co.uk), NICEIC or NAPIT for electrical work, FMB (Federation of Master Builders) for general building, and NHBC or similar for new builds. Third, ask for and follow up on at least two references from similar past projects. Fourth, verify they have appropriate public liability insurance (minimum £2 million) and employer's liability insurance. Which? Trusted Traders, Checkatrade, MyBuilder, and Rated People all offer varying levels of vetting and public review systems.

Project Management Tips

For projects lasting more than a week or involving multiple trades, good project management makes a significant difference to both cost and stress levels. Create a detailed written specification of all works before inviting quotes — this ensures all contractors are pricing for the same scope. Establish a clear communication protocol: daily site visits are appropriate for large projects, and agree how variations and additional costs will be handled in writing before work starts. A contingency budget of 10–15% is strongly recommended for any structural work, as hidden problems (damp, rot, asbestos in pre-1980 homes, deteriorated electrics) frequently emerge once walls are opened. For complex projects involving multiple trades, consider hiring a project manager or architect to oversee works — their fee (typically 10–15% of project value) can save significantly through better contractor management and procurement.

Frequently Asked Questions

How much does a kitchen renovation cost in the UK in 2025?

A basic kitchen renovation starts from £8,000–£12,000 for a standard fit-out. Mid-range costs £12,000–£18,000 and high-end/luxury kitchens run £20,000–£35,000+. London prices are 25–30% higher.

How much does a loft conversion cost in the UK?

A Velux loft conversion costs £20,000–£35,000. A dormer conversion costs £35,000–£55,000. Hip-to-gable or mansard conversions cost £45,000–£70,000. Loft conversions typically add 15–20% to property value.

Do I need planning permission for a home extension?

Many extensions qualify as permitted development (no planning required). Single storey rear extensions up to 4m (detached) or 3m (other) are typically PD. Always check with your local planning authority, especially in Conservation Areas.

How much does a single storey extension cost per square metre?

Typically £1,500–£2,500/m² for a standard build, or £1,750–£3,250/m² in London. A 20m² kitchen extension costs approximately £30,000–£50,000 in most of England.

How do I find a reliable tradesperson in the UK?

Use Which? Trusted Traders, Checkatrade, or MyBuilder. Always get 3+ written quotes, check trade registration (Gas Safe, NICEIC, FMB), verify insurance, and follow up on references. Never pay in full upfront.

Which home improvements add the most value?

Loft conversions add ~15–20% of property value. Extensions add 10–15%. Kitchen and bathroom renovations add 5–10%. A new boiler or roof adds value by removing a major defect that would deter buyers.

What VAT rate applies to home improvement work?

Most building work is 20% VAT. Energy-saving materials (insulation, heat pumps, solar) are 0% VAT since February 2024. Properties empty 2+ years qualify for 5% reduced VAT on renovation work.

How should I structure contracts and payments?

Always use a written contract with a staged payment schedule tied to completion milestones. Pay no more than 10–25% upfront. Retain 10% until all snagging is resolved. Use FMB or JCT Minor Works contracts for larger projects.

Official Sources

GOV.UK - Planning Permission
Checkatrade Cost Guides 2025
Federation of Master Builders
Gas Safe Register
Which? Trusted Traders

Mustafa Bilgic

Property and construction cost specialist. Cost data sourced from Checkatrade, RICS, and FMB industry benchmarks, updated quarterly. Learn more about our team.

Home Improvement Cost Calculator UK