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What The Average Cost Of A Loft Conversion?

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The Cost Of A Loft Conversion

It’s a question asked by thousands, ‘how much does a loft conversion cost?’ But it might as well be, ‘how long is a piece of string?’ The costs for loft conversions can vary greatly depending on the type of loft extension you opt for, along with what you do to said loft conversion. There are also other factors to consider from your location all the way down to the type of staircase for your loft conversion you decide to have installed. 

While an exact price may not be possible to ascertain without an in-depth consultation, we can give you a better idea of what’s possible by giving you some average prices for varying loft conversions to date. 

From the roof structure to the need for planning permission and more, please remember any average costs are exactly that, average and will of course be subject to change.

1) Velux Loft Conversion – otherwise known as ‘room in a roof’ loft conversion, the Velux loft conversion. This is most likely the cheapest and quickest way to convert your loft however it’s worth noting that while it does save on cost, time and of course disruption, it’s only possible to do so if you already have enough space in your loft to play with. It usually consists of adding insulation, a staircase, skylights, electrics, lighting, heating and any fire safety measure.

2) Dormer Loft Conversion – dormer loft conversions are one of the most popular out there. They’re an incredibly versatile choice, allowing you to extend either at the back or side of your property (planning permission permitting). They add on a great amount of space inside too however once again, will vary on cost depending on how many dormers you add. Prices vary depending on the size and/or house they are being built on, please contact us for a quote.

3) Hip To Gable Loft Conversion – this is a super popular option and involves converting the sloped side of the roof, otherwise known as the ‘hip’, into a flat edge in order to provide additional space inside of the loft. Again hip to gable loft conversion prices will vary depending on what else you have done inside it would be best to contact us for a quote.

4) Mansard Loft Conversions – Mansards and L-shape Mansards are amongst the most expensive type of loft conversion, but do add great value to your property.

Speak To Us About Loft Conversions


Contact Clapham Construction Today

If you’d like more help and information on loft extensions, or would like to book in a free consultation with our team, contact Clapham Construction Service on 0203 950 7957 or email us via [email protected]. We also offer a design and planning service to help you achieve the amazing loft conversion you want. Our team will be only too happy to take a look at your loft space, discuss your desired outcome and give you an estimate of the cost to achieve your dream loft conversion. 

As London’s leading loft conversion specialists, we’ll guide you throughout the entire process to ensure you know what’s happening and when. We ensure transparency throughout, especially regarding price and will always respect your budget from the very beginning.

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How Much Does a Loft Conversion Cost? 2023 Guide

Understanding how the costs add up enables you to make the most out of your planned investment. In this price guide we will provide you with all the elements and variables to make the best decisions when investing in a loft conversion.

How much does a loft conversion cost?

Depending on your location within the UK, the price of a loft conversion will vary. Furthermore, the type of conversion and the legal and technical constraints placed upon it will also play a key role in determining the likely cost. Excluding likely finishes such as windows, flooring, and sanitary ware, the typical cost of a loft conversion will cost between £1,200 and £2,000 per square metre.

The variation in the cost per square meter depends on the type of loft conversion, the size of the alterations to the roof, the access, the type of finishing and the location.

Special projects to develop the roof space in period buildings can require higher investments. In prime locations, they can double the value of a property after they’ve been completed, like this roof development project in Chiswick, London we completed in 2019.

Rooflight loft conversion

It requires the installation of rooflight windows in the roof to allow sunlight to enter the loft. It usually includes strengthening of the existing floor, flooring, insulation, plasterboarding and installation of rooflights. They are generally allowed under permitted development outside conservation areas and other designated areas. For more information on permitted development rights for householders you can visit the official government web site.
With a rooflight conversion you keep the alterations to a minimum. This means the result will be basic, without budget for plumbing, extensive electrical work etc.

The average rooflight loft conversion cost in the UK can be between £15,000 to £25,000.

Dormer loft conversion

This consists of a boxed-shape structure that replaces one of the slopes of a pitched roof. The result is a flat-roofed space that allows the installation of full-sized windows and the use of full-height furniture and other appliances. They are sometimes allowed under permitted development when not in designated areas.

The cost is higher than that of a roof light conversion, as it requires the complete rebuilding of one roof pitch plus the full associated internal works.

The average cost of a standard dormer loft extension is between £25,000 and £50,000. For an L-shaped dormer, it can go from £40,000 to £75,000.

Hip-to-gable loft conversion

In end-of-terrace or detached properties, the roof slope at the end of the terrace or of the detached house is replaced with a vertical brick wall. It is combined with a dormer conversion to maximise the space. The alterations to the roof are extensive and you need to build a brick gable wall, as opposed to the stud wall needed for the dormer conversion.

The average cost of a hip-to-gable conversion is higher than a dormer extension, and can go between £32,000 and £60,000.

Mansard loft extension

A mansard loft conversion creates a flat roof space, with four or two of the external walls gently sloped. It can extend to create an additional storey on top of an existing building. It is an extensive building alteration and it always requires planning permission.This design is the most expensive option for a loft conversion.

The average cost of a mansard loft extension can go from £40,000 to £70,000, assuming the mansard covers the extension of the loft only.

How location can change the loft conversion cost

When discussing the topic of building works, there is no one-size-fits-all.  This is reflected in the costs, too. In general, building works are cheaper where the property market prices are lower.

Much of the variation is due to the nature of expensive property areas: generally they are busier, more densely built and inhabited. This translates into higher costs, for multiple reasons. For example:

  • Building site access: in a busy metropolitan city, often there is no or very little space for parking, placing machinery, scaffolding, rubbish skips etc
  • Cost of labour: in a place with a higher cost of living, the workers are paid higher salaries or daily rates
  • Cost of materials and deliveries: because of the higher salaries, rent cost of commercial space, constraints in the size of transporting vehicles and distance from production plants, prices for supplies are higher in metropolitan areas.

For a better idea of the most expensive and the cheapest areas in the UK, as an average:

  • Scotland and South East England are the most expensive, with peaks in Edinburgh and London
  • Northern Ireland is the cheapest area for building costs in the UK

Explanation of the professional fees

When planning any building works, you will need to consider professional fees   in addition to the building costs.   Even if planning permission is not required, you will still need drawings of your loft conversion to be produced for the council, the building regulation officers and for the building teams.

Ensuring the drawings are produced by a professional is always a sensible approach as they minimise the likelihood of miscalculation and incorrect information. Producing and submitting unclear or incorrect requirements and measurements can cause both delays and mistakes that can be very expensive to rectify at a later point.

Planning fees

Whilst loft extensions can often be completed without planning permission, you will still need to file for a Certificate of Lawfulness from your council. This will cost approximately £100.

Fees for filing for the planning permission differ amongst the councils and heavily depend on the amount of work the planning authorities need to process the application. Householder applications, required for extensions and garden buildings, are around £210.

For more information on the planning process and fees across the UK, you can visit the Planning Portal.

Design fees

For a loft conversion, you will need to produce at least building regulation drawings. For a standard loft conversion, the design fees would be between £1,000 to £2,000.

Furthermore, you will need to budget for structural calculations, such as whether  a new beam or other structural alterations are required. The fee for the structural design will range from £900 to £1,800 for a standard loft conversion.

Design and the associated drawings produced for a loft conversion planning application, can cost between £1,000 and £3,500.

Keep in mind  that design costs can vary substantially, depending on the architects you appoint and the complexity of the design A cheaper alternative is to appoint a consultant, rather than choosing an architectural practice. Alternatively you can choose to hire a design and build company, who will quote for your loft conversion including the design fees. In some cases, the planning fees will also be included in a design and build quotation.

Party wall fees

If your loft conversion will need building work to a wall that sits astride a boundary you will need Party Wall agreements with all the neighbours that share that party wall with you.

This is very often the case in terraced or semi detached properties, or if you are extending a flat in a block. The typical cost of a party wall agreement depends on whether your neighbours and you will want or need to appoint a party wall surveyor.

Typically, party wall agreements will cost £700 to £1,500 per neighbour.

Keep in mind it is possible to serve the notices yourself without the need to pay for a surveyor if your neighbour agrees on the proposed work, and they don’t appoint a surveyor themselves.

Building control fees

You will need a Building Control certificate at completion, which certifies that all the work is in compliance of building regulations. The average cost for a loft conversion is approximately  £750, depending on the size and the nature of the works.

You can liaise directly with the local authority or engage a government-approved inspection company. Both will check that the work is carried out in compliance and will issue the certificate at completion.

The loft conversion cost can increase if…

Whenever a loft conversion project is not a standard one, costs can increase accordingly. The most common reasons why the budget can be higher than the average are:

Number of parties involved in the party wall process:
The higher the number of parties involved, the higher the cost of party wall agreements. Plus, any dispute causes delays and even more additional costs.

Complex structural design and implementation:
Your loft extension might need more beams or columns than the average, or the shape or the design might require specific structural solutions.

Building access:
Any constraint on the accessibility of the site can significantly increase the costs.

Age and conditions of the existing building:
When making structural alterations to an old building, surprises can happen while stripping out. It’s not uncommon that some of the existing joists and beam will need strengthening or replacement that cannot always be planned ahead.

Height of the existing building:
For high buildings, like blocks of flats, the cost of transporting the materials onto the site. So are scaffolding and rubbish removal.

Finishes and interiors:
Any bespoke solution has an impact on the cost of a loft conversion. High end finishes also cause an increase compared to the average costs.

Project duration:
If you have tighter timelines for completion than the average, the project will need more workers on site at the same time. Delivery of materials can also be affected. This means higher logistics and organisational costs, also considering there is a maximum in the number of people who can work on a loft conversion at the same time, without interfering with each other’s work.

How much should you spend on a loft conversion?

When planning building works to your home, it’s important to consider how much value the alterations will add to the current property. It is recommended to consult local estate agents, to better understand the potential sale price of properties in your area where a loft extension was added.

Once you understand the increase in value that a loft conversion could add to your property value, you can use that figure to support many decisions in the course of the project. Design solutions, finishes, space, lighting etc can be evaluated and selected, according to your understanding of the investment return.

This is an excellent way to stay in control of your budget and be confident that the extension is a worthwhile investment.

Get Your Free Quote Today

If you are planning a loft conversion, get in touch regarding any questions and support you may need; you can also book a free site visit and free quotation from our specialised teams.

Contact us now


Vinz is the CEO and co-founder of houseUP. He is a true authority in financial planning and risk management, coming from years of working in financial services and digital payment industries

5 tricks for creating an interior in loft style :: Design :: RBC Real Estate

Loft is industrial chic. His ideology is simplicity and shocking. An interior in this style can be created in an ordinary city apartment. Here’s how to do it

Photo: Aaron Huber/Unsplash

The history of the loft originates in France in the 19th century. Creative intelligentsia from all over the world came to Paris and looked for spacious premises for workshops and studios. But due to high prices, artists could only afford to rent attic rooms. Later this European culture was adopted by the Americans. And since there were no attics like those in Paris in America, the local bohemia moved to abandoned warehouses and factories. In the early 30s of the 20th century, the Great Depression hit the United States, and the owners moved their industrial enterprises outside the cities. The empty industrial premises in the center began to be rented out. So the first lofts appeared in the USA. In English, loft means the attic of a production facility.

The famous artist Andy Warhol made a breakthrough in style. His art studio The Factory has become the most famous loft in America. Warhol developed his aesthetic principles: primitivism, minimalism and emphasis. The latter was the main discovery of Andy Warhol. The loft-style interior is a rough background and a few bright accents.

To create such an interior does not require large financial costs. The principle “the simpler the better” works here. It is enough to plaster the walls and create an imitation of brickwork, sand the floor and paint the old wooden windows. There are only a few restrictions: you should not decorate a children’s room, hallway, kitchen or bathroom in this style. Best of all, this design will look in the living room. And it will be the most advantageous option for spacious studios.


Open space, or open space, high ceilings and large windows are the main advantages of lofts. It fills the room with air and light. Lofts use a minimum of partitions and divide the space with multi-level floors, bar counters, shelving or sofas. Separate zones can be highlighted with bright colors by painting the walls in them.

Photo: Aaron Huber/Unsplash

The base of the loft-style interior is an unfinished brick, concrete or wood wall. Less often, the ceiling is used in this capacity. If the load-bearing walls in the apartment are brick, you can expose the masonry, then the unique texture and color of the brick will be the perfect backdrop for the interior. If you are not planning a large-scale alteration, you can create an imitation of brickwork using special tiles. Typically, the interior uses a traditional terracotta shade, but for a modern interpretation, you can choose white or black brickwork.

Photo: Anna Sullivan/Unsplash

Industrial details become key elements of the style: ceilings and beams, metal supports, stairs, old radiators. Loft-style interior does not require expensive furniture. It should be simple and comfortable: an old leather sofa, a grandmother’s chest of drawers, a metal bed. The main rule is not to place furniture close to the walls, because the interior of the loft implies a free layout and open space. An old carved chest of drawers can be combined with plastic furniture, crystal lamps – with modern household appliances. A hammock or a swing suspended from the ceiling, ladders instead of shelving will fit perfectly.

Photo: Anna Sullivan/Unsplash

Be sure to allocate space in the interior for art objects. Pictures, advertising posters, pin up posters are best placed on the windowsill or directly on the floor, leaning against the wall. A vintage radio or a retro fridge is ideal. The main principle is that accessories should be non-standard. The wall can be decorated with graffiti.

Photo: Alexandra Gornago/Unsplash

The main palette of the loft interior is natural colors. Most often, designers use earthy shades. They can be diluted with white, black and red. Andy Warhol added another color – silver. At The Factory, everything was painted silver. If you want to follow the example of a famous artist, a few silver accents in the interior can be a good solution.

Loft style – fashion trend of the XXI century

The new century brought with it a change in the technological order. The percentage ratio of “white” and “blue” collars has changed in a mirror way, and along with this, industrial premises, located, as a rule, in the centers of large cities, have been vacated. Gradually, they began to adapt to offices and apartments, so the “Loft” appeared – the most popular style of business real estate today.

The very word “loft” means in English – “attic”. It originated in New York City in the 1940s and began precisely with the transformation of the abandoned attics of former industrial buildings into informal offices, the culture of which was radically different from the prim and “buttoned” traditional office. Representatives of creative professions – designers, artists, musicians – settled in the first lots, arranging galleries and creative workshops in them. The clearest example is Andy Warhol’s The Factory. However, over time, a number of competitive advantages such as high ceilings, solid construction, good lighting, open floor plan and low rental rates have made lofts attractive to developers. In an effort to minimize repair costs, loft owners often left the brick walls in their original form, the wiring ran along the top, and many authentic metal objects remained in the interior. As a result, on the one hand, a brutal industrial style was obtained, but on the other hand, it was quite cozy and warm, and most importantly, low-cost in decoration.

Very soon, the list of professionals who prefer loft to glass and concrete towers expanded greatly. Today, loft-style premises are among the most sought after in the commercial and residential real estate market around the world.

Despite the rather long history of the style, “lofts” became truly widespread only in the 2000s, when the vast majority of large cities in the world entered the post-industrial phase of development.

“Loft” perfectly fit into the changing aesthetics of megacities. Russian cities are also no exception. Huge premises of empty workshops of plants and factories, often still pre-revolutionary buildings, had to be used. Most modern Moscow lofts are located in pre-revolutionary or pre-war buildings. Vivid examples of the loft architecture of modern Moscow are the Danilovskaya Manufactory and Red October complexes. A distinctive feature of “Danilovka” is the presence of not only office space, but also their combination with apartments and a hotel. As a result, we got a mini-city in the same style on the banks of the river.

Residential loft

The premises of the industrial zones built in the second half of the 20th century, as a rule, are demolished due to the impossibility of recycling due to low-quality materials and a rather unsightly appearance. The organization of the space of such premises, without violating their historical identity, is not an easy task, but the “loft” coped with it perfectly.

Modern lofts are divided into several classes:

“Hard lofts” – “Hard loft” – in this case, an existing building is used to create new residences;

“Soft lofts” – “Soft loft” – remodels specially designed and built in this style;

“Commercial loft” – usually industrial spaces, with a minimum ceiling height of 5 meters, used for commercial purposes;

“Residential loft” – adapted for living quarters, however, as a rule, such lofts do not have official residential status and are apartments.

Today, living or working in a loft is considered a sign of good taste. Often, even ordinary apartments in panel houses, as well as Soviet office buildings, the owners try to design “loft-like”.

Is it worth it, and if so, how?

If you are thinking about creating a loft interior, it is better that your house or office was built no later than the 40s of the last century, it was brick and with a large living space. As an option, you can decorate modern large-sized housing in the “loft-like” style, but experimenting with classic panel “Khrushchev” or “Brezhnevka” is still not worth it in order to avoid the effect of Soviet “brick-like” wallpaper. Two-level apartments are ideal for equipping a loft space. It would be nice if these apartments were open plan.

Zoning in a loft apartment is best done with the help of furniture, placing bright accents so that the loft does not lose its “industrialism”, but at the same time does not become too harsh. For example, on the ground floor of a two-level apartment, you can place a bathroom and a kitchen, which would become the center of the entire space. For a loft, muted “natural” colors are better suited: brown, slate, white, the picture is complemented by artificial aging of interior items, worn parquet boards, “steampunk” braid for wiring.

Designer lamps made in vintage style and placed in the apartment will add authenticity.

One of the most important elements of the loft style is the floor. It should have a fairly “old” look with a “worn” effect, it is better if it is a natural, artificially aged tree. Parquet, parquet board and ceramic tiles in the loft will look out of place. Natural, and even stylized wood is too expensive. The optimal solution for laying the floor in the loft is Alpine Floor spc laminate.

A large assortment of tile models made under natural wood will allow you to solve any design problem in the design of a loft. In addition to the price, vinyl flooring has such advantages over natural wood as its absolute moisture resistance, ease of installation that does not require special skills, wear resistance for more than 2 decades with intensive use, resistance to fungal infections, and independence from humidity conditions. The appearance and texture of Alpine Floor quartz-vinyl coatings are indistinguishable from the original wood.

Alpine floor in the loft interior. Model – ECO182-7 Country Oak

If the walls in the future loft are still not brick, but concrete, then it is recommended to cover them with tinted wax to give them a noble and “old” look.
The main finishing material for the walls of the loft is plywood, it can be used to decorate window slopes and build a podium, under which to remove communications.