Overview of Loft Conversion Costs
Loft conversion costs in the UK for commonly range from £25,000 for a basic rooflight (Velux) conversion to £70,000+ for higher-spec builds like mansards and complex structural changes. Your final price depends on conversion type, floor area, structural work, finishes, access constraints, and regional labour rates.
What’s Included in a Typical Quote?
A comprehensive loft conversion quote usually includes design and build elements such as structural steelwork, new floor joists, insulation, roof alterations (where required), windows or dormer construction, stairs, first and second fix electrics, plastering, and final finishes. Some contractors include building control inspections and certification, while others list these separately—so always confirm what’s included.
Key Factors That Affect Loft Conversion Price
A realistic quote typically depends on:
- Conversion type: rooflight (Velux), dormer, hip-to-gable, or mansard. See our full guide to all loft conversion types.
- Floor area: larger m² typically increases materials and labour, but can reduce cost per m².
- Structural complexity: steelwork, chimney removal, purlin changes, or roof strengthening.
- Staircase design: the position and complexity can significantly affect build cost.
- Bathrooms: plumbing runs, ventilation, tiling, and higher spec fixtures increase cost.
- Finish level: standard vs premium specification (doors, flooring, lighting, joinery).
- Access: tight access, scaffolding requirements, parking and waste removal can add cost.
- Compliance: insulation standards, fire doors, mains interlinked smoke alarms, egress windows.
Planning Permission vs Permitted Development
Many UK loft conversions fall under permitted development, but there are exceptions—especially for mansards, homes in conservation areas, flats, listed buildings, or designs that exceed volume limits. If planning is required, you may need drawings and formal submission, which is why the calculator includes a planning allowance.
Party Wall Agreements
If you share a wall with a neighbour (terrace or semi-detached), your work could fall under the Party Wall etc. Act. This can involve notices, surveyor fees, and formal agreements—especially if steelwork bears into the party wall. Not every project needs it, but it’s common enough to be included as an optional cost in the calculator.
How Region Impacts Your Price
London and the South East often command premium rates due to labour costs and demand. Northern regions like Manchester and the Midlands including Birmingham can be more competitive. The estimate uses a regional multiplier to reflect common differences in market pricing.
Common Loft Conversion Types
| Conversion Type | Typical Range |
|---|---|
| Rooflight (Velux) | £25,000 – £40,000 |
| Rear Dormer | £40,000 – £55,000 |
| Hip-to-Gable | £50,000 – £65,000 |
| Mansard | £55,000 – £70,000+ |
Build Times and “When to Start”
Your “start date” can affect overall cost due to contractor availability, seasonal demand, and lead times for materials. If you need to start ASAP, you may see a higher estimate to reflect fast scheduling and limited availability.
How to Use This Estimate
The calculator provides a realistic range to help you budget and compare options. Your formal quote may differ depending on site surveys, structural engineering requirements, and the final specification. After submitting your details, we connect you with local specialists who can provide written quotes.