Embarking on a home renovation in the UK is an exciting prospect, but it can quickly become overwhelming when faced with contractor quotes and material costs. Whether you are tackling a minor cosmetic update or a full-scale ‘rip-out-and-start-again’ project, having a clear understanding of the financial landscape is essential to avoiding budget overruns.
This guide breaks down the typical costs for the most common renovation projects across the country, providing you with the key figures you need to plan your project successfully.
Phase 1: Full House Renovation Costs (The ‘Big Picture’)
A full renovation often involves structural changes, updating old systems, and a complete aesthetic overhaul. The price varies dramatically depending on the size of your property, its age, its current condition, and your desired level of finish.
1. Typical Full House Renovation Averages
The cost is usually calculated per square metre ($\text{m}^2$) of floor area, though many quotes are provided as a single lump sum.
| Property Size | Low Spec (Basic Refresh) | Mid Spec (Standard Finish) | High Spec (Bespoke/Luxury) |
| 1-Bed Flat | £20,000 – £40,000 | £40,000 – £65,000 | £65,000+ |
| 3-Bed House | £50,000 – £75,000 | £75,000 – £100,000 | £100,000 – £150,000+ |
Key Takeaway: The average cost to fully renovate a typical 3-bed house in the UK currently sits around £76,690 (Mid-Benchmark, 2024/2025 data).
2. System and Essential Upgrades
These are the non-negotiable costs for older homes that often need system modernisation for safety and efficiency.
| Project | Average Cost Range | Notes |
| Full House Rewiring | £4,000 – £8,500 | Essential for homes built pre-1970s. Varies by number of circuits. |
| New Heating System | £3,000 – £8,500 | Includes new boiler, pipework, and radiators. |
| Damp Proofing Course (DPC) | £500 – £5,000 | Price depends on whether it’s chemical injection or structural membrane. |
| New Roof Installation | £6,500 – £18,000 | Major variability based on material (tile vs slate) and roof size/pitch. |
| Full Replastering (Re-skim) | £5,000 – £12,500 | Cost depends on whether walls are stripped back to brick or just re-skimmed. |
Phase 2: Major Extensions and Conversions
These projects add significant space and, typically, the most value, but they come with the highest price tags.
3. Kitchen Extensions (Single-Storey)
The most popular form of renovation, the cost is usually quoted per $\text{m}^2$ of new internal space.
| Level of Finish | Cost per m2 (Excl. VAT) | Example 30 m2 Shell Cost |
| Basic | £1,500 – £1,750 | £45,000 – £52,500 |
| Good Quality | £1,700 – £2,100 | £51,000 – £63,000 |
| Excellent/Bespoke | £2,100 – £3,000+ | £63,000 – £90,000+ |
London Factor: Expect costs in London and the South East to be 15% to 25% higher than the national average. A premium London extension can easily reach £3,000 – £5,000 per $\text{m}^2$.
4. Loft Conversions
| Type of Conversion | Typical Cost Range | Notes |
| Velux/Rooflight | £15,000 – £30,000 | Simplest type; minimal structural work; keeps roofline. |
| Dormer | £30,000 – £60,000 | Most popular; adds head height and usable floor area. |
| Hip-to-Gable | £40,000 – £65,000 | Used on semi-detached houses with ‘hipped’ roofs. |
| Mansard | £45,000 – £75,000+ | Requires the most work; creates a near-vertical wall; often requires full planning permission. |
Phase 3: High-Impact Rooms
The kitchen and bathroom are where the majority of the budget for fixtures and fittings is spent.
5. Kitchen & Bathroom Costs
These areas are heavily influenced by your material choices, from ‘off-the-shelf’ units to fully bespoke cabinetry and high-end sanitaryware.
| Project | Low/Mid Spec Range | Mid/High Spec Range |
| New Kitchen (Units/Worktops) | £7,000 – £12,500 | £12,500 – £30,000+ |
| Appliances | £1,500 – £4,000 | £4,000 – £10,000+ |
| New Bathroom | £5,000 – £8,000 | £8,000 – £15,000+ |
| Cloakroom/WC | £1,500 – £2,500 | £2,500 – £5,000+ |
Phase 4: Non-Construction and Hidden Costs
Your build budget is just one part of the equation. You must account for the professionals, permits, and inevitable surprises.
6. Professional Fees and VAT
| Cost Item | Typical Charge | Notes |
| Architect/Design Fees | 5% – 15% of Total Build Cost | For drawings, planning applications, and design. |
| Structural Engineer | £500 – £3,500 | Essential for calculations on extensions/load-bearing wall removals. |
| Planning Permission | Circa £210 (England) | Required for extensions beyond Permitted Development. |
| Building Control Fees | £500 – £1,500 | Mandatory for all structural changes to ensure compliance. |
| Party Wall Agreements | £1,000 – £1,800 per neighbour | Needed if building near or on a boundary wall. |
| VAT (Value Added Tax) | 20% on all labour and materials | Applied to most construction work. This is a huge factor. |
7. The Golden Rule: Contingency ⚠️
No renovation runs perfectly. Unexpected structural issues (dry rot, subsidence, faulty electrics) are common, especially in older British housing stock.
Always allocate a contingency fund of 10% to 20% of your total budget. If you spend £100,000 on the project, you need an extra £10,000 to £20,000 ring-fenced for surprises.
💡 Top Budget-Saving Strategies
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Prioritise the Structure: Spend money on the ‘envelope’ (roof, foundations, insulation, and essential systems like wiring and plumbing) first. You can always upgrade tiles and taps later.
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Smart Design: Work with your architect to design an extension that uses standard sizes and fewer complex angles. Every corner, beam, and bespoke feature adds significant cost.
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Owner-Supplied Materials (Fixtures & Fittings): Source your own kitchens, tiles, and sanitaryware. You may save money by buying direct and can often negotiate better deals than your builder’s supplier.
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Consider a Shell Build: For large conversions (like a loft or extension), ask the builder to complete the ‘shell’ (structure, roof, windows, exterior finish) and then hire a cheaper team or take on the ‘second fix’ trades (plastering, electrics, plumbing, decorating) yourself.
