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Loft conversions in Surrey have become one of the most practical ways to add space and value without relocating. But the first question most homeowners ask is simple – how much will it cost? The answer depends on the type of conversion, the size of the space, the condition of the roof, and the level of finish expected. Below is a full breakdown of costs, build options, and what to expect if you’re planning a loft extension in Surrey.
Average Loft Conversion Costs in Surrey
Prices vary depending on the type of loft conversion. Here’s a clear outline of average costs:
- Velux Loft Conversion: from £25,000 to £35,000
- These are the simplest. No major structural changes. You keep the existing roofline. It’s essentially about fitting rooflights, insulation, flooring, and stairs.
- Dormer Loft Conversion: from £35,000 to £55,000
- Adds usable headroom. Flat-roofed dormers are common in Surrey. Suitable for most mid-terrace and semi-detached homes.
- Hip to Gable Loft Conversion: from £45,000 to £65,000
- Ideal for end-of-terrace or detached properties. Extends the sloping side roof to create a vertical wall, giving more internal space.
- Mansard Loft Conversion: from £60,000 to £85,000+
- Offers the largest increase in floor area. Requires planning. You get full-height rooms across most of the loft.
- Bungalow Loft Conversion: from £40,000 to £80,000+
- Bungalows in Surrey offer large footprints. Often converted with rear dormers, full-width bathrooms, and two bedrooms.
What Affects the Final Price?
Several factors influence what you’ll pay:
- Size of the loft– Larger lofts cost more due to labour and materials.
- Roof structure– Cut roof or trussed? Trussed roofs need more steelwork.
- Plumbing and electrics– Moving or adding bathrooms or complex heating systems will raise costs.
- Finish level– Basic finishes are cheaper. Premium fittings and built-in storage increase the price.
- Access– Staircase design and placement can add unexpected costs.
- Planning and building regulations– Some conversions need planning approval. All must meet building control standards.
Planning Permission and Regulations
Most loft conversions fall under permitted development. However, if your property is in a conservation area or you’re planning a Mansard conversion, you’ll likely need full planning permission. Surrey councils differ in how they interpret planning rules, so it’s best to check with your local authority before starting. Every conversion must meet Building Regulations. These cover fire safety, insulation, head height, and staircase design. You’ll need a structural engineer and building inspector sign-off.
Build Timeframes
On average:
- Velux conversions: 4–6 weeks
- Dormer or hip-to-gable: 6–10 weeks
- Mansard conversions: 10–14 weeks
Timescales can shift due to weather, planning issues, or structural surprises. Always allow extra time.
Will It Add Value?
Yes. A well-executed loft conversion in Surrey can increase a home’s value by 15% to 25%, depending on location and quality. Adding an extra bedroom with an en-suite can lift a three-bed semi into the four-bed market, often adding tens of thousands in resale value.
Loft Conversion in Surrey
Choosing the right team is key. When comparing quotes, make sure all structural work, insulation, plumbing, electrics, and finishes are included. If you’re considering a loft conversion in Surrey, ensure the quote is fully detailed and covers architectural drawings, permissions, and structural calculations.
Summary of Costs
| Conversion Type | Approximate Cost |
| Velux | £25,000 – £35,000 |
| Dormer | £35,000 – £55,000 |
| Hip to Gable | £45,000 – £65,000 |
| Mansard | £60,000 – £85,000+ |
| Bungalow | £40,000 – £80,000+ |
Final Notes
Costs rise with complexity. Build time increases with design detail. But value always lies in getting it right the first time. Loft conversions are one of the best ways to grow your space without moving. For Surrey homeowners, they’re a smart, lasting investment.
