How Much Is a Loft Conversion UK?

If you're asking how much is a loft conversion in the UK, you're not alone. At RPCB Prime, it's one of the most common questions we get from homeowners looking to unlock extra living space without moving. Whether you're after a guest bedroom, a new office, or a full en-suite master suite, a loft conversion can be one of the smartest investments you make in your home.

In this blog, I’ll break down the average cost of different types of loft conversions in the UK, what affects pricing, and how to budget realistically—so you can plan with clarity and confidence.

💷 Average Loft Conversion Cost UK

Loft conversion prices in the UK vary depending on the size, complexity, and style of the conversion. Here's a rough breakdown of average costs in 2025:

Loft Conversion TypeEstimated Cost RangeVelux (Rooflight) Conversion£20,000 – £30,000Dormer Loft Conversion£35,000 – £55,000Hip to Gable Conversion£45,000 – £65,000L-Shaped Dormer£50,000 – £70,000Mansard Loft Conversion£60,000 – £80,000+

💡 Note: Prices vary based on property type, location, materials, and finishes.

🛠️ What Influences the Cost of a Loft Conversion?

There’s no one-size-fits-all price for a loft conversion. The final quote depends on several factors, including:

1. Type of Loft Conversion

Each style has a different structural requirement:

• Velux Loft Conversion Cost UK: Most affordable, as it requires minimal structural changes.

• Dormer Extension Price UK: Higher due to the need for roof alteration, additional framing, and more complex finishes.

• Mansard Loft Conversion Cost UK: Highest price point, as it involves major changes to the roof structure and often needs planning permission.

2. Size and Layout

The larger the space, the more materials and labour you’ll need. Want an en-suite bathroom? That adds plumbing, tiling, ventilation, and fittings to your budget.

3. Structural Work & Stairs

If new steel supports are required or a staircase needs to be cut into your existing layout, this can increase costs.

4. Finishes and Fixtures

Are you going high-end with hardwood flooring, bespoke wardrobes, and spotlights? Or keeping it functional and simple? Your taste will shape your budget.

5. Planning Permission and Building Regulations

While many conversions fall under permitted development, some—like a Mansard loft extension or front-facing dormer—will require full planning permission. You’ll also need to factor in architect fees, structural calculations, and inspection costs.

📍 Loft Conversion Cost by Region

Prices also vary based on your location:

• London & South East: Usually 10–20% more expensive than national averages due to labour and material costs

• Midlands & North: Slightly more affordable, but still impacted by design complexity

• Rural areas: May incur extra charges for transport and access

📈 Does a Loft Conversion Add Value to My Home?

Absolutely. A well-executed loft conversion can increase your home's value by up to 20%, depending on your location and design.

This makes it not only a practical upgrade—but also a smart financial decision, especially if you’re planning to sell in the future.

💡 How to Budget for a Loft Conversion

At RPCB Prime, we recommend budgeting with a small buffer for unexpected costs. Here’s a helpful guide:

ItemCost EstimateArchitect & Drawings£1,500 – £3,000Planning Application (if needed)£200 – £300Structural Calculations£500 – £1,000Building Regs/Inspections£500 – £1,500Main Build CostSee table aboveInterior Finishing (flooring, etc)£3,000 – £10,000+

✅ Tips to Keep Costs Under Control

1. Have a clear plan before starting—avoid changing layouts mid-build

2. Work with a reputable builder (like us!) who offers transparent pricing

3. Choose cost-effective materials that still look great

4. Stick to a timeline—delays cost money

5. Get multiple quotes but don’t always go for the cheapest

🔍 Real-World Example: Dormer Conversion in London

We recently completed a dormer loft conversion in South London for a growing family. The project included a double bedroom, en-suite, and storage space. The final cost came to £54,000, which included custom carpentry, Velux skylights, and underfloor heating. The property value increased by £85,000 within 12 months of completion.

🙋‍♂️ Frequently Asked Questions

How much is a basic loft conversion UK?
A simple Velux conversion typically starts around £20,000, with minimal disruption and no major structural work.

How much is a dormer loft conversion UK?
Expect to pay between £35,000 – £55,000 depending on size, finishes, and region.

Is a loft conversion cheaper than an extension?
Yes, loft conversions are generally more affordable and less invasive than ground-floor extensions.

Can I get a quote before committing?
Of course. At RPCB Prime, we offer free consultations and detailed quotes so you know exactly what to expect.

Do you offer finance or staged payments?
Yes—we offer flexible payment options so you can spread the cost with peace of mind.

🏡 Final Thoughts

So, how much is a loft conversion in the UK? It depends on your style, space, and vision—but with proper planning, a loft conversion can be a life-changing (and value-adding) investment.

If you're thinking about starting a project, our team at RPCB Prime is here to help. From initial surveys to the final brushstroke, we’ll guide you through every step—on time and on budget.