The Cost Of Loft Conversions in London 2024: A Complete Guide


Are you a London homeowner contemplating gaining extra space with a loft conversion? If so, you’re not alone. With property prices continually on the rise in our capital city, many residents are turning to converting roof space to maximise living space without the hassle of moving. However, before you embark on this exciting journey, it is essential to understand the cost of loft conversions. In this comprehensive guide, we will share loft conversion prices so you have all the information you need to start making informed decisions about your home improvement project.

Understanding Loft Conversion Costs

According to the good people at check-a-trade, on average, loft conversion costs in the UK vary considerably. The most expensive, at £65,000 to £75,000, are Mansard and Bungalow conversions. A simpler Velux loft conversion could be, in contrast, as little as £27,500. The average cost of a loft conversion in London is likely to be higher than the UK nationwide figure by up to 20% This is due to higher labour costs and, occasionally, the type of project. Many London properties have limited access, for example, which can make work take longer.

Loft conversion quotes are often given per metre squared. Some suppliers allow you to price the work through an online loft conversion cost calculator, for example. Loft conversion cost per m2 should, however, only be used for guidance. You must always get a detailed quote from any building contractor based on a home visit and survey. Surprises tend to add to the cost of any loft conversion which is something to be avoided.

Understanding Loft Conversion Costs

You can contact the Red Box loft conversion team at any point and we will be delighted to give you a no-obligation quote based on visiting your property and hearing about your loft conversion plans.

Many factors influence the cost of any loft conversions including the size and complexity of your idea, your property’s existing structure, the materials and finishes you have in mind and your location. We’ve discussed each quickly below.

loft size

Size and Complexity

The size and complexity of your loft conversion will have a significant impact on the overall cost. Larger conversions or those requiring structural alterations will naturally incur higher expenses. It is important to discuss your loft conversion plans in detail with any contractor. At Red Box, we love to hear about families’ dreams of more space – the bigger and more challenging the better!

Design and Specifications

The design and specifications of your loft conversion will also influence the cost. Features like en-suite bathrooms, bespoke fittings, and skylights can add to the overall expense. It is helpful to come up with a shopping list divided into ‘must-haves’ and ‘nice-to-haves’ as there might be a degree of compromise involved in getting a loft conversion at the right price.

Labour Costs and Professional Fees

Labour costs and professional fees for London loft conversions vary depending on factors such as project complexity and location. Expect to allocate between £15,000 to £40,000 for labour including skilled tradespeople like carpenters and electricians. Professional fees covering design and architectural services, project management and other services are easy to forget.

Planning and Building Regulations

Obtaining planning permission and ensuring compliance with building regulations are essential steps in the loft conversion process. Costs associated with planning applications, surveys, and building regulations should be factored into your budget whether you do the work yourself or ask a contractor like us to handle the paperwork.

Materials and Finishes

The choice of materials and finishes will affect both the quality and cost of your loft conversion. Opting for high-end materials and finishes will inevitably increase expenses, but they are likely to last longer than cheaper options. Aiming for the cheapest loft conversion possible initially risks costly repairs and maintenance in years to come.


The location of your property within London can impact the cost of a loft conversion. Factors such as accessibility, proximity to amenities and even the ability to park near your property can all influence pricing. This is why we always recommend a site visit as part of any quotation. It avoids location-based surprises once the work starts.

Loft Conversion Architect Cost

Complex loft conversions may require the services of an architect. Certainly, if you are making material changes to the structure of your home, it pays to consult with a design expert. In the UK, loft conversion architect costs typically range from £1,500 to £5,000, depending on the complexity of the project and the architect’s experience and reputation.

Additional Expenses and Contingency Planning

While reputable suppliers will minimise the risk of additional expenses, unplanned events might occur during any loft conversion. It is therefore sensible to include a contingency figure in any loft conversion budget. This can vary depending on the complexity of the project but should form part of any loft conversion quotation.

loft location

Loft Conversion Costs by Type 2024

A loft conversion involves transforming an underutilised attic space into a functional room. This typically means an additional bedroom, office or additional living area such as a kid’s playroom or ‘man-cave’. It is also a handy way to add value to their property and create extra space without the need for an extension. Not all loft conversions are the same though, which has a significant impact on pricing. We have shared the main types below together with UK average costs.

Roof Light Conversion

Also known as a Velux conversion, this type of loft conversion involves adding windows to the existing roof structure without altering its shape.

It’s typically the most cost-effective option and, in the majority of cases, doesn’t require planning permission.

The average price of a London Velux conversion might be around £45,000.

Roof Light Conversion
Dormer Conversion

Dormer Conversion

A dormer conversion extends the existing roof to create additional headroom and floor space.

This type of conversion is popular for properties with limited loft space and can significantly enhance the usability of the attic area.

The cost of a dormer conversion in London might, on average, reach £65,000.

Hip-to-Gable Conversion

This type of conversion involves extending the hip roof to create a vertical gable wall, effectively maximising the available loft space.

It’s ideal for properties with hipped roofs and can provide substantial additional living space.

This comes at a cost though. Average London costs start at £75,000.

Hip To Gable Conversion
mansard conversion

Mansard Conversion

Mansard conversions entail replacing one or both slopes of the existing roof with steeply sloping walls, effectively creating a full additional storey.

While more complex, they offer maximum headroom and space utilisation but this makes them, typically, the most expensive option.

Mansard loft conversion costs in London are roughly £80,000.

Maximising The Value Of Your London Loft Conversion

Looking at the figures above, it is clear a London loft conversion will always be a significant investment. However, they can also offer an excellent return by adding value to your property at the point of sale. If this is your intention, there are some tips below to help maximise the value of your loft conversion.

Quality workmanship

Quality Workmanship

You can ensure a quality loft conversion project by choosing reputable contractors with a proven track record of delivering high-quality work. Quality workmanship will not only enhance the aesthetics and functionality of your space but also ensure longevity and durability. It is always going to be a factor that future purchasers will be looking for.

Energy Efficiency & Sustainability

Green energy-efficient features such as insulation, double-glazed windows and efficient heating systems will add significantly to the value of your loft conversion. Not only will this reduce your energy bills, but it will also appeal to eco-conscious buyers in the future.

Functional Design & Amenities

Opt for a design that maximises the functionality and usability of your loft space. Consider the needs and preferences of potential future buyers and tailor the design accordingly. Consider adding amenities such as en-suite bathrooms, built-in storage and custom fittings too. They will always enhance the appeal and value of your loft conversion.


A loft conversion can be a transformative addition to your London home. A conversion is likely to provide valuable additional living space and enhance its overall appeal and value. However, it is essential to approach the project with careful planning and consideration of costs. By understanding the factors that influence the cost of loft conversions and taking steps to maximise value, you can embark on this exciting home improvement journey with confidence.