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Last updated: 12 April 2024

Loft Conversion Cost: A Comprehensive Price Guide in the UK

  • On average, a basic loft conversion for 20m2 (215.3 square feet) can start from around £20,000 to £30,000, while more extensive and luxurious conversions can cost upwards of £50,000 or more.
  • It’s crucial to obtain quotes from multiple contractors and discuss specific requirements to get an accurate estimate for your project.

Loft conversions are a popular way to maximize space and add value to a property in the UK. Whether you’re looking to create an extra bedroom, a home office, or a playroom, converting your loft can be a cost-effective solution compared to moving house.

In this comprehensive price guide, we’ll break down the various factors that influence loft conversion costs in the UK.

What is the Cost of a Loft Conversion in the UK?

The cost for a basic loft conversion covering an area of 20m2 (215.3 square feet) is approximately £20,000 to £30,000. Meanwhile, larger and more luxurious conversions cost up to £50,000 or more. For example, a 2 bedroom loft conversion price in mansard design usually varies from £57,000 to £75,000. The cost of a loft conversion in the UK can vary widely depending on several factors, including the location of the property, the size and type of the loft conversion, and the complexity of the work involved.

Type of ConversionCost per m2 (£)
Velux/Roof Light Loft Conversion£1,000 – £1,500
Dormer Loft Conversion£1,500 – £2,500
Mansard Loft Conversion£1,800 – £3,000
Hip-to-Gable Loft Conversion£1,200 – £2,000
Modular Loft Conversion£1,800 – £2,500
Basic Loft Conversion (Standard Finish)£1,200 – £1,800
Two-Bedroom Conversion£2,500 – £4,000

Note: Costs are estimates and can vary based on factors such as location, size, complexity, materials, and finishes.

Attic Conversion Cost By Type

Attic or loft conversions come in various types, each offering its own set of benefits and cost considerations. Expenses may rise due to factors such as incorporating luxurious finishes, increasing the number of windows, constructing a new staircase, selecting specific flooring, and installing a bathroom.

Additionally, the overall costs are influenced by the project’s location and the weather conditions. Adverse weather can lead to delays in the project’s timeline.

Below, we’ll explore the typical costs associated with different types of attic conversions in the UK.

1. Velux Conversion:

A Velux conversion, also known as a roof light or skylight conversion, is one of the most cost-effective options for converting your attic space. It involves adding roof lights or skylights to an existing attic without altering the roof’s structure significantly.

On average, a Velux conversion for a 20 m2 can cost between £15,000 to £25,000, depending on the size of the attic, the number of roof lights required, and any additional features such as insulation and flooring.

2. Dormer Conversion:

Dormer conversions are popular because they provide additional headroom and floor space by extending the existing roof vertically. There are different types of dormers, including flat roof, gable-fronted, and hipped roof dormers, each with its own cost implications.

Dormer conversions for a 20 m2 typically range from £20,000 to £40,000, depending on the size and complexity of the dormer, as well as any structural alterations required.

3. Hip-to-Gable Conversion:

A Hip-to-Gable conversion involves extending the hip roof to create a gable end, providing more internal space. This type of conversion is ideal for properties with a terraced and hipped roof design.

Hip-to-gable conversions for a 20 m2 can cost between £30,000 to £50,000, depending on the size of the attic, the extent of structural work required, and any additional features.

4. Mansard Conversion:

Mansard conversions are the most complex and expensive option, as they involve changing the shape of the roof to create a nearly vertical wall. However, they can provide the maximum amount of additional living space.

Mansard conversions are often the most expensive. For a 20 m2 ranging from £40,000 to £70,000 or more. The high cost is due to the extensive structural alterations and custom design required for this type of conversion.

5. Bungalow Conversion:

Converting the attic space in a bungalow can be a great way to add extra living space without extending the footprint of the property. Bungalow conversions may involve various types, including Velux, dormer, or Mansard conversions, depending on the property’s design and structural constraints.

Bungalow attic conversions for a 20 m2 typically range from £20,000 to £50,000, depending on the type of conversion chosen and the size of the attic space.

6. Modular Conversion:

Modular loft conversions involve prefabricated units that are installed onto the existing structure, minimizing disruption and construction time. These conversions can be a faster and more cost-effective option compared to traditional methods.

Modular loft conversions for a 20 m2 can cost between £20,000 to £40,000, depending on the size and complexity of the modules, as well as any additional features required.

Breaking Down Loft Conversion Prices

  1. Velux Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£15,000 to £25,000
Architect (7% to 10% of total cost)£1,050 to £1,750
Structural Engineer£500 to £1,000
Builders/Contractors£10,000 to £20,000
Plumbers/Electricians£1,000 to £2,000
Other Professionals (Surveyors, etc.)£450 to £750
The completion time for Velux loft conversions typically ranges between 4 to 6 weeks, although this can differ depending on the specifics of each project.
  1. Dormer Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£20,000 to £40,000
Architect (7% to 10% of total cost)£1,400 to £2,800
Structural Engineer£600 to £1,200
Builders/Contractors£12,000 to £24,000
Plumbers/Electricians£1,500 to £3,000
Other Professionals (Surveyors, etc.)£700 to £1,400

The completion time for Dormer loft conversions typically ranges between 10 to 12 weeks, although this can differ depending on the specifics of each project.
  1. Hip-to-Gable Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£25,000 to £45,000
Architect (7% to 10% of total cost)£1,750 to £3,150
Structural Engineer£750 to £1,500
Builders/Contractors£15,000 to £27,000
Plumbers/Electricians£2,000 to £4,000
Other Professionals (Surveyors, etc.)£900 to £1,800

The completion time for Hip-To-Gable loft conversions typically ranges between 10 to 12 weeks, although this can differ depending on the specifics of each project.
  1. Mansard Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£40,000 to £70,000
Architect (7% to 10% of total cost)£1,500 to £3,500
Structural Engineer£500 to £2,000
Builders/Contractors£20,000 to £40,000
Plumbers/Electricians£1,500 to £3,500
Other Professionals (Surveyors, etc.)£500 to £1,500

The completion time for Mansard loft conversions typically ranges between 10 to 12 weeks, although this can differ depending on the specifics of each project.
  1. Bungalow Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£25,000 to £50,000
Architect (7% to 10% of total cost)£1,750 to £3,500
Structural Engineer£750 to £1,500
Builders/Contractors£16,000 to £32,000
Plumbers/Electricians£2,000 to £4,000
Other Professionals (Surveyors, etc.)£900 to £1,800

The completion time for Bungalow loft conversions typically ranges between 10 to 12 weeks, although this can differ depending on the specifics of each project.
  1. Modular Loft Conversion (20m²):
Expenses and ServicesPrice (£)
Average total cost£30,000 to £60,000
Architect (7% to 10% of total cost)£2,100 to £4,200
Structural Engineer£900 to £1,800
Builders/Contractors£18,000 to £36,000
Plumbers/Electricians£2,500 to £5,000
Other Professionals (Surveyors, etc.)£1,100 to £2,200

The completion time for Modular loft conversions typically ranges between 2 to 3 weeks, although this can differ depending on the specifics of each project.

Construction Materials

When converting a loft, choosing the right construction materials is crucial for achieving both structural integrity and energy efficiency. Here’s a breakdown of essential construction materials needed for a loft conversion, along with insights into their costs and environmental impact


Insulation is vital for regulating temperature and energy efficiency in the loft space. Common insulation materials include fiberglass, mineral wool, and rigid foam boards.

Insulation costs can vary depending on the type and thickness of the material. On average, expect to pay between £20 to £50 per square meter for insulation materials.

Opting for eco-friendly insulation materials such as recycled fiberglass or natural wool can reduce environmental impact. Additionally, proper insulation can lead to long-term energy savings by reducing heating and cooling costs.


The cost of windows depends on factors such as size, material, and glazing options. Expect to pay between £300 to £1,500 per window, depending on specifications.

Consider installing energy-efficient windows with double or triple glazing to improve thermal performance.

Energy-efficient windows can reduce heat loss and energy consumption, leading to lower carbon emissions and utility bills over time.

Roofing Materials

Common roofing materials include tiles, slates, and metal roofing. Roofing material costs vary depending on the type and quality of the material. On average, roofing materials can cost between £40 to £100 per square meter.

If you aim to enhance the sustainability of your project and home, consider utilizing recycled metal or clay tiles for your roof. Choosing recycled materials can frequently offer a more cost-effective option. Additionally, durable roofing materials can minimize the need for frequent repairs or replacements, saving money in the long run.


The cost of stairs depends on the design, material, and complexity of installation. Expect to pay between £1,000 to £5,000 or more for staircase materials and installation. Consider options such as spiral stairs or space-saving designs to maximize floor space in the loft.

When you choose and plan your staircase, you have the opportunity to integrate natural materials, encouraging sustainability in your design decisions. Moreover, you could consider reclaimed wood as an alternative, which may offer a more economical and environmentally conscious choice. Additionally, choosing space-saving staircase designs can optimize the use of space in the loft.

Fixtures and Fittings

Fixtures and fittings include items such as lighting fixtures, plumbing fixtures, and hardware. Fixture and fitting costs vary depending on the brand, quality, and specifications. Budget between £500 to £3,000 or more for fixtures and fittings in a loft conversion.

Energy-efficient fixtures such as LED lighting and low-flow plumbing fixtures can reduce energy and water consumption, leading to long-term cost savings and environmental benefits.

General Building Materials

General building materials include structural components, framing lumber, drywall, and finishing materials.

General building material costs can vary depending on the quantity and quality of materials selected. Budget between £5,000 to £20,000 or more for general building materials in a loft conversion project.

Opt for sustainable building materials such as FSC-certified lumber, recycled drywall, and low-VOC paints. Choose high-quality, durable materials that will ensure the longevity of your loft conversion. Additionally, durable materials require fewer replacements, reducing waste and resource consumption over time.

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Professional Services

When converting a loft in the UK, various professional services are essential for a successful project. The expenses can fluctuate significantly and hinge on several factors including size, type of conversion, intricacy, and unforeseen complications. Additionally, residing in an urban area as opposed to a rural setting may result in higher costs.

Here’s a breakdown of these services and their typical charges for a loft conversion:

  1. Architectural Services: Architectural fees can vary based on the complexity of the project and the reputation of the architect. Typically, architectural fees for a loft conversion can range from £1,500 to £5,000 or more. Employing an architect is optional, but having one will guarantee that the conversion is carried out correctly.
  2. Structural Engineer: Structural engineers usually charge by the hour or a flat fee based on the scope of work. For a loft conversion, expect to pay between £500 to £2,000 for structural engineering services.
  3. Building Contractor: On average, contractor fees for a loft conversion can range from £15,000 to £40,000 or more. Building contractors typically provide quotes for the entire project, including labour, materials, and their profit margin. The cost of contractor fees for a loft conversion can vary widely depending on factors such as the size of the loft and the level of finish desired.
  4. Electrician: Electricians typically charge an hourly rate or a fixed price for specific tasks. For a loft conversion, electrical work can cost between £1,000 to £3,000 or more, depending on the extent of wiring, installation of fixtures, and electrical upgrades required.
  5. Plumber: Plumbers may charge by the hour or provide quotes for specific plumbing tasks. For a loft conversion with a bathroom or kitchenette, plumbing costs can range from £1,500 to £5,000 or more, depending on the water pressure and also if there are already existing plumbing pipes.
  6. Scaffolder: Scaffolding costs can range from £500 to £2,000 or more, depending on the size and height of the property. Scaffolding is essential for working at height and allows tradespeople to carry out tasks such as roofing, cladding, and window installation safely.
  7. Roofing Specialist: Expect to pay between £1,000 to £5,000 or more for roofing services. Roofing specialists may charge by the hour or provide quotes for specific roofing tasks. The cost of roofing services for a loft conversion can vary based on factors such as the condition of the existing roof, the need for repairs or replacements, and the type of roofing materials used.
  8. Insulation Specialist: Insulation specialists typically provide quotes based on the size of the loft and the type of insulation materials required. The cost of insulation for a loft conversion can range from £500 to £2,000 or more, depending on factors such as insulation type, installation complexity, the type of material being used, amount of material needed and the complexity of the roof.

It’s essential to obtain detailed quotes from multiple professionals and factor in all associated costs when budgeting for a loft conversion project in the UK.

Labour and Timescales

Here’s a timeline for a loft conversion to provide you with a clearer understanding of when various labor costs occur.

Assessment and Planning (2 to 3 Weeks)

Evaluate whether your loft is suitable for conversion, taking into account factors such as ceiling height, roof type (traditional framed or modern truss), and available space.

This phase involves consulting with a contractor or architect to discuss your aspirations, needs, and financial plan for the loft transformation.

Permissions and Design (Up to 12 Weeks)

Although many conversions may fall within the scope of “permitted development,” it is advisable to consult local regulations or enlist the expertise of an architect.

Design the Layout:

  • Define the intended function of the space (e.g., bedroom, office, playroom).
  • Consider aspects like storage solutions, lighting arrangements, and ventilation systems.
  • Incorporate elements such as skylights or dormer windows to optimize natural light.
  • Ensure proper insulation to maintain comfortable conditions throughout the year.

Construction (8 to 12 Weeks)

Demolition and Preparation:

  • Clear the loft area of any existing structures or belongings.
  • Strengthen the floor structure if necessary.


  • Implement insulation and lay down flooring.
  • Arrange for the installation of electrical wiring and plumbing systems.
  • Establish safe access points, which may involve installing a spiral staircase or conventional stairs.
  • Fit windows or roof lights to enhance natural illumination.
  • Construct walls and ceilings to define the space.

Finishing Touches:

  • Select appropriate colour schemes, furnishings, and decorative elements.
  • Install smoke alarms to ensure safety compliance.
  • Maximize space utilization by integrating built-in storage solutions within eaves and alcoves.

Quality Control and Final Inspections (1 to 2 Weeks)

  • Verify that all work meets established safety and quality standards.
  • Obtain the required certifications and approvals before concluding the project.

What Affects Loft Conversion Cost In The UK?

Factors influencing the cost of loft conversions in the UK are multifaceted and can significantly impact budgetary considerations. Here are a few that you may need to consider.

  • Roof Type and Structure:
    The complexity of your roof structure and its type (e.g., pitched, hipped, or trussed) can influence the cost. Some trussed roofs are difficult to convert. Conversions on more complex roof structures may require additional structural support or alterations, impacting overall expenses.
  • Size and Layout:
    The size of the loft and the layout of the conversion play a significant role in determining costs. Larger lofts require more materials and labour, while complex layouts or the addition of ensuite bathrooms may increase expenses.
  • Age and Condition of the House:
    Older properties may require more extensive structural work or upgrades to meet building regulations. Issues such as damp, rot, or inadequate insulation may need addressing, adding to the overall cost.
  • Plumbing and Electrical Needs:
    The inclusion of plumbing fixtures, such as bathrooms or kitchens, and electrical installations, such as lighting and sockets, will impact costs. Extending plumbing and electrical systems to the loft space can require additional work and materials.
  • Location:
    Local regulations and planning requirements can vary across different regions in the UK. Factors such as conservation areas, listed buildings, or greenbelt restrictions may affect the feasibility and cost of a loft conversion. Building expenses in London and the South East typically surpass those in other areas. In sought-after urban centers, both materials and skilled professionals may command premium rates.
  • Party Wall Agreement:
    If your property shares a wall (party wall) with a neighbouring property, such as mid-terraced or semi-detached houses, you may need a Party Wall Agreement. Terraced houses in the middle require party wall agreements on both sides of the property, resulting in higher costs. The process involves notifying adjoining owners and can incur additional legal and surveying fees.
  • Quality of Materials and Finishes:
    The choice of materials and finishes, such as flooring, insulation, windows, and fixtures, can significantly affect costs. Opting for high-quality or bespoke materials will increase expenses compared to standard options.
  • Contractor and Professional Fees:
    Hiring experienced professionals, including architects, engineers, builders, and tradespeople, will incur fees that contribute to the overall cost. Quality workmanship and expertise may come at a premium but can ensure a successful and durable loft conversion.

Tips and Strategies to Lower Loft Conversion Costs in the UK

  • Set a Budget: Before you begin, establish a clear budget for your loft conversion. Having a financial plan will guide your decisions and prevent overspending. You should also consider having 10% of your budget in your savings account for any issues or unexpected costs.
  • Choose the Right Contractor: Selecting a reliable and experienced contractor is crucial. Compare quotes from different professionals and consider their track record. Negotiate prices and ensure transparency about costs. You can also read reviews and talk to individuals who have converted their home lofts.
  • Use Existing Structure: Utilize the existing structure of your home whenever possible. This can significantly reduce costs compared to major structural changes.
  • Optimize Space: Efficiently use the available space. Consider space-saving strategies like built-in storage solutions, multifunctional furniture, and smart layouts to maximize the room’s potential.
  • DIY Options: If you have the skills and time, consider doing some of the work yourself. DIY tasks like painting, decorating, or minor carpentry can save money. But keep in mind that if you lack the necessary skills, it’s advisable to hire a professional, as mistakes could lead you to spend higher repair costs later on. Additionally, if you opt for a do-it-yourself approach, you must still adhere to rules and regulations.
  • Consider a Velux Conversion: Velux loft conversions are the most cost-effective option. They involve adding roof windows to an existing loft space, providing natural light and ventilation. While they offer less additional space, they are simpler and more affordable.
  • Negotiate with Contractors: Don’t hesitate to negotiate prices with contractors. Obtain multiple quotes and discuss cost-saving measures.
  • Use Reclaimed Materials: Consider using reclaimed wood, recycled tiles, or other sustainable materials. Not only does this reduce costs, but it’s also environmentally friendly because they are kept off from ending up in landfills.
  • Careful Planning: Plan meticulously. Proper planning avoids costly mistakes and ensures efficient use of resources.
  • Prioritize: Focus on essential features first. Prioritize what matters most to you, whether it’s additional space, aesthetics, or functionality.

Checklist for Reducing your Loft Conversion Costs

  1. Create a Detailed Plan:
    – Define your objectives, budget, and timeline.
    – Consider unexpected costs and allocate a contingency fund.
  1. Explore Cheaper, Budget-Friendly Loft Conversions:
    – Consider alternative approaches, such as Velux conversions or modular options.
    – Explore cost-effective designs that meet your needs.
  1. Source Your Own Materials:
    – Shop around for materials and compare prices from different suppliers.
    – Consider using reclaimed or recycled materials to save costs.
  1. Get Multiple Quotes for Comparison:
    – Obtain quotes from several contractors or specialists.
    – Compare their prices, services, and expertise.
  1. Find a Registered Loft Conversion Specialist:
    – Prioritize specialists registered with reputable trade schemes.
    – Check if they are part of the Competent Tradesperson Scheme to avoid additional approval costs.
  1. Select Your Own Fixtures and Fittings:
    – Choose fixtures and fittings yourself to tailor the design to your preferences and budget.
    – Avoid markup costs from contractors by sourcing your own materials.
  1. Hire a Specialist:
    – A specialist can ensure the work is done correctly, avoiding future problems and expenses.
    – Consider their expertise in loft conversions.
  1. Partially DIY Your Loft Conversion:

If you have relevant skills, consider doing some tasks yourself:

  • Lay laminate or tiles.
  • Paint and decorate.
  • Install lights and sockets.

Remember that each loft conversion project is unique, so adapt these strategies to your specific circumstances. Careful planning and informed decisions will help you achieve a cost-effective and successful loft conversion.


Swathi Subhash Nair
Written by Swathi Subhash Nair, External Writer

Swathi’s journey in the field of content creation began with her education in journalism, where she developed a deep understanding of the power of words and the importance of effective communication.

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