Loft Conversions

Outgrown your space or keen to add lasting value to your home? A loft conversion can give you the extra living space you need and save you the hassle and expense of moving. It can also significantly improve your home’s saleability.

As a loft conversion company in London with 17 years+ experience, Red Box has worked in all property types creating new bedrooms, bathrooms, playrooms, studies and great home offices. Sloped ceilings are perfect for storing books.

Whatever style is best for your property – roof light, dormer, hip-to-gable or mansard – as a trusted company, our builders in South West London will ensure you get a finished product that is right for the style of your home and within your budget. We also specialise in home repairs, bespoke extensions and other building projects – take a look at our gallery for some inspiring examples.

Other Loft Conversion Locations

Wandsworth Loft Conversion


Chiswick Loft Conversion Thumbnail


Loft Conversion Putney Barnes Thumbnail

Putney & Barnes

Loft Conversion Kensington


Loft Conversion Hammersmith


Fulham Loft Conversion


Conversion Types


There are four main project types – roof light, dormer, hip-to-gable and Mansard. The best style for your home will depend on the type and age of your house as well as your budget.

Many projects are covered by permitted development rights and won’t need planning permission unless you live in specific areas.

A Mansard conversion, however, will nearly always requires planning consent as they change the roof shape and structure.

Loft Conversion Cost

What is a roof light conversion?

A roof light loft conversion (also known as Skylight or Velux) is the simplest type of project.

They don’t involve changes to the shape and pitch of the roof.

They simply require skylight windows, a proper floor and a staircase to make the room more accessible.

As a result, the cost tends to be less than for a dormer, mansard or hip-to-gable project.

What is a Hip-to-gable conversion?

Hip-to-gable projects are only suitable for semi-detached and detached houses as they need a free sloping side roof. They work by extending the sloping ‘hip’ roof outwards to create a new vertical ‘gable’ wall. This creates valuable extra space for a bedroom, bathroom or home office.

A hip-to-gable project cost is typically higher than for other terraced, detached and semi-detached options as it involves changing the roofline. If you have a detached house with sloping roofs either end, you have the option of a double hip-to-gable extension.

What is a Mansard conversion?

A Mansard extension is the most dramatic and space making option. This style extension runs the whole length of your home’s roof and features a flat roof, with the back wall sloping inwards at an angle of 72 degrees.

Windows are usually fitted within small dormers which extend from the roof to project light into the new space.

Loft Conversion Ideas

Mansard is a popular detached, semi-detached and terraced house style as it makes the most of lofts and attics by effectively adding another floor to your home. It especially appeals to homeowners who want more space without the hassle of moving. A Mansard extension can be added to the property’s rear or front if permission allows.

Interested in a Mansard style conversion? From Victorian terraces to 1930s semi-detached houses, we have converted lofts in a variety of properties in South West London and beyond. Contact us for free and impartial advice on the best style for your needs.

Extension Project Costs?


One of the first questions a client will ask Red Box is ‘how much is a loft conversion’? The price depends on many factors, from the type of extension you want, to where you live and whether you need planning permission. The average price of a basic project cost starts at around £22,000 but the higher cost of materials and labour in London means that cost may start at around £30,000. Loft conversion prices UK-wide will also be influenced by the age and style of the property and the type of work you want.

Space is a precious commodity for London homeowners, and a home extension can be one of the best ways to achieve that coveted extra space. If you’re on a budget, a basic loft conversion with a roof light may be the best way to convert your space quickly and affordably.

On the upper scale, a full double Mansard or dormer conversion will maximise your upstairs space. but the loft conversion cost UK-wide might be between £35,000 to £50,000, due to the structural changes and new roof required. You’ll also need to factor in stair costs to ensure the space is safe to access too.

When it comes to finding the average cost of loft conversions in your area, do plenty of research and ask for very detailed quotes. Prices can also be reduced by researching and choosing your own fixtures and fittings. Check out our list of recommended products and suppliers.

Want to know how much does a loft conversion cost when you instruct Red Box? Many homeowners across South West London have trusted Red Box in their homes. Contact us for a free quote.

Loft Conversion

Loft Conversion Uses


A loft can be a lot more than a place for storage. With judicious planning, a standard or truss roof loft conversion can create a stylish bedroom for guests, a quiet space to work or even a gym. Some homeowners also use a small loft conversion as a walk-in closet or a low ceiling loft conversion as a kids’ playroom or gaming space.

A bedroom loft conversion is by far the most popular reason for converting a loft. A 2 or 3 bed semi-detached loft conversion can create much-needed room for a growing family. Adding a one or two-bedroom loft conversion with ensuite can also add 20% to your property value, making it a great investment if done well.

Whether you are already working with an architect or need help from the start, our team of loft conversion specialists will help you get the most from this unused space. From new build loft conversions to a period home loft conversion bedroom or bathroom, whatever your style property or needs we can help you create the home you want.


Loft Conversion Design

Loft Conversion Stairs

A cleverly designed layout is vital to getting the loft of your dreams. Red Box loft conversion specialists can plan and manage every aspect of your home improvement project. Starting with an initial visit, we’ll discuss your needs and loft conversion design ideas before issuing a loft conversion quote and realistic time frames. We can also recommend a local loft conversion architect and show you some loft conversion designs.

If you’re wondering ‘how long does a loft conversion take?’ the simple answer is it depends on the style of the conversion and whether it falls under permitted development rights or whether you need planning permission. If you are altering the roof height or shape it is probable that you will need planning consent, which can take over eight weeks. Additional features such as loft conversion insulation, storage or windows can also be built into the quote.

Once the build is complete, our designers and painters can decorate your new space. As members of the Professional Decorating Association and Which? Trusted Traders, you can be confident the finish to your home will be beautiful and long-lasting.

Loft Conversions London


Red Box is an established South London loft conversion company. A Which? Trusted Trader, we carry out fine property renovation and loft conversions across South West London and Surrey. Our client base stretch from Fulham, Wandsworth, Balham, Clapham, Kensington, Shepherds Bush, Richmond, Teddington, Twickenham, Wimbledon and Putney to Surrey.


Alongside being top-rated loft conversion specialists in London, Red Box undertakes everything from extensions and installations through to property maintenance and decorating. If you have a residential or commercial property, call us to arrange a free site visit and quotation. For examples of projects, see our gallery of past projects including loft conversions in West London and beyond.

Loft Conversions Near Me

Why Choose Red Box

We specialise in home improvements, extensions, kitchen fitting and bathrooms as well as the associated services of plumbing, electrical and full decoration work.

Our team work closely with architects and designers, either engaged by us or which you may have already engaged. We are happy to follow your design or work with you on a design to fit your budget and taste.

We’d love to hear from you!

For any questions please fill out the quick form on the right to drop us an email and we will be in touch.

Kitchen Fittes London

Kitchen Fitters London

Bathroom Renovations

Bathroom Renovations

Painters and Decorators

Painters and Decorators

Home Maintenance Service

Home Maintenance Service

House Extensions

House Extensions

Very Professional and Great Quality "Red Box carried out a complete renovation and internal restructuring of my home, were hyper efficient, sympathetic to plan alterations, on time and on budget! I have nothing but praise for their work and would thoroughly recommend their work on others." MORE PROJECTS HOUZZ REVIEWS