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Last updated: 26 March 2024

Small Loft Conversion Costs: A Comprehensive Guide 2024

A comprehensive guide to Small conversion costs in the UK.
  • The average cost of a small 20m2 loft conversion in the UK can be anywhere between £15,000 to £40,000.
  • A Velux conversion for a small loft conversion in the UK can range from between £15,000 – £30,000. Dormer loft conversion will cost you approximately £20,000 – £40,000. If you choose Hip-to-Gable, it can range around £25,000 – £45,000. And a Mansard loft conversion can cost you £40,000 – £70,000+
  • Professional fees for architects, structural engineers, and builders, as well as planning permissions and building regulations, also contribute to the overall cost.

In 2024, the typical expense for converting a small loft in the UK ranges between £15,000 and £40,000. However, this cost can vary significantly due to several factors including the type of conversion, the size and complexity of the loft, materials utilised, location, and more.

Loft conversions have increasingly gained popularity among UK homeowners as a means to expand living space without relocating. Particularly in urban areas where space is limited, transforming the loft into a functional room can substantially enhance a property’s value.

For individuals contemplating a small loft conversion, having a grasp of the associated costs is essential for effectively planning and executing the project. This article presents a comprehensive overview of anticipated expenses and dives deep into several factors that can affect the cost. 

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How Much Does a Small Loft Conversion Cost?

The costs associated with small loft conversions can vary widely depending on factors such as location, size of the loft, desired features, and quality of materials used. However, we can provide some general average costs to give you an idea:

Average costs for small loft conversions:

  • Basic small loft conversion: £15,000 – £25,000
  • Standard small loft conversion: £25,000 – £35,000
  • High-end small loft conversion: £35,000 – £50,000+

These costs typically include materials, labour, permits, and other associated expenses. It’s important to note that these are rough estimates and actual costs may vary.

The table below  provides a comparison between small and large loft conversions in terms of cost, size, complexity, additional features, return on investment, and duration of conversion. 

AspectSmall loft conversionLarge loft conversion
Cost Range£15,000 – £50,000£40,000 – £100,000+
Size of the Loft15-25m230m2 +
Complexity of ConversionLess complexMore complex
Additional FeaturesLimited spaceRoom to add features
Return on Investment (ROI)High (due to low investment)High (due to added value)
Duration of ConversionShorter timeLonger time

Keep in mind that these are general comparisons and actual costs and outcomes may vary depending on individual circumstances and requirements.

Example of costs for a small loft conversion

Example small loft conversion.

Let’s consider a real-life example of the costs associated with a small loft conversion:

Location: London, UK

Type of Property: Terraced House

Size of Loft: Approximately 15m2 (160 square feet)

Conversion Type: Basic Loft Conversion

Cost Breakdown:

  • Architectural drawings and planning application: £1,000 – £2,000
  • Reinforcing loft floor structure: £500 – £1,000
  • Adding structural beams if required: £1,000 – £2,000
  • Insulation (walls, floor, roof): £500 – £1,000
  • Flooring (laminate, carpet, or hardwood): £500 – £1,000
  • Roof windows (such as Velux): £1,000 – £1,500
  • Electrical wiring and lighting fixtures: £500 – £1,000
  • Installation of staircase or ladder: £1,000 – £2,000
  • Installation of basic plumbing for a bathroom: £1,000 – £2,000
  • Adding heating (such as radiators or underfloor heating): £1,000 – £2,000
  • Plastering and painting walls and ceiling: £1,000 – £1,500
  • Skirting boards, architraves, and other finishing touches: £500 – £1,000
  • Contingency fund (10-15% of total budget): £2,000 – £3,000

Total Average Estimated Cost:

  • Low End: £10,000
  • High End: £20,000

Please note that these costs are estimates based on typical prices in the London area and can vary depending on factors such as the quality of materials used, complexity of the project, and specific requirements of the homeowner.

 It’s always advisable to obtain multiple quotes from reputable contractors and professionals before undertaking any construction project.

What affects small loft conversion prices?

Small loft conversion cabin.

A small loft conversion cost can indeed vary widely based on several factors. Here’s a breakdown of some key factors that influence small loft conversion prices:

  1. Size of the loft: Naturally, the size of the loft space plays a significant role in determining the cost. A larger loft will require more materials and labour, resulting in higher overall costs.
  2. Type of conversion: The type of conversion you’re aiming for will also impact the cost. A basic conversion to create a single room will generally be less expensive than a more complex conversion involving multiple rooms, a bathroom, or extensive structural changes.
  3. Materials used: The quality and type of materials chosen for the conversion will affect the overall cost. Higher quality materials typically come with a higher price tag but may offer better durability and aesthetics in the long run.
  4. Structural work required: If the loft requires structural changes such as reinforcing the floor, adding support beams, or altering roof structures, the cost will increase accordingly due to the complexity and labour involved.
  5. Access and staircase: Creating safe and convenient access to the loft space, whether through a staircase or a loft ladder, will add to the overall cost. A staircase may require structural modifications and additional space, leading to higher costs compared to a ladder. 
  6. Windows and lighting: Installing roof windows for natural light and ventilation, as well as electrical wiring for lighting fixtures, will contribute to the overall cost. More number of windows, higher quality windows and lighting options may increase costs but can enhance the functionality and aesthetics of the space.
  7. Insulation and heating: Proper insulation is essential for maintaining comfortable temperatures and energy efficiency in the converted loft. Adding insulation and heating systems, such as radiators or underfloor heating, will incur additional costs but can improve comfort and energy efficiency.
  8. Location: Construction costs can vary depending on the location and local labour rates. Urban areas and regions with higher living costs may have higher construction costs compared to rural areas.
  9. Planning and permits: Obtaining necessary planning permissions and building permits can add to the overall cost of the project. Fees for architectural drawings, planning applications, and permit approvals should be considered in the budget.
  10. Contingency fund: Typically, this fund ranges from 10% to 15% of the total project cost. It’s always wise to allocate a contingency fund for unexpected expenses or changes during the construction process.

Consulting with experienced contractors or architects can also provide valuable insights and guidance tailored to your specific requirements and budget constraints.

Considering these factors and carefully planning your small loft conversion project can help you estimate and manage the costs effectively. 

Cost by size

One key factor that influences the cost of a loft conversion is its size. We delve into this concept providing insights into how the area of your loft affects the overall expenditure.

A basic loft conversion cost in the UK typically starts from around £20,000 to £30,000. However, more complex conversions or those with higher-end finishes can cost upwards of £40,000 to £50,000 or more.

To better understand the cost implications, let’s break down the average costs per square meter (m2) for small loft conversions. Here’s a table summarising the estimated costs for different sizes:

Loft size (m2)Estimated cost (£)Average cost per m2 (£)
15£15,000 – £27,000£1,000 – £1,800
25£25,000 – £40,000£1,000 – £1,600
30£30,000 – £45,000£1,000 – £1,500
35£35,000 – £53,000£1,000 – £1,500
40+£40,000 – £60,000+£1,000 – £1,500
Note: The costs provided above are estimates and can vary based on various factors such as location, complexity of the conversion, materials used, and additional features like plumbing or electrical work.

Cost by type of conversion

Type of conversionCost range (£)
Velux£15,000 – £30,000
Dormer£20,000 – £40,000
Hip-to-Gable£25,000 – £45,000
Mansard£40,000 – £70,000+

In the UK, loft conversions come in various types, each with its own characteristics, benefits, and associated costs. While the size of the loft might be small, you may still have options to explore and combine different types of conversions to maximise space and functionality. 

Here’s a breakdown of the costs by type of conversion commonly seen in the UK:

Velux loft conversion:

Velux loft conversions involve adding roof windows (often called Velux windows) to the existing roof structure to create a bright and airy space without altering the roofline.

Velux conversions are generally the most cost-effective option due to their simplicity. Costs typically range from £15,000 to £30,000 depending on the size of the loft and the number of windows installed.

Dormer loft conversion:

Dormer loft conversions extend vertically from the existing roof, creating additional headroom and floor space. They usually involve the construction of a box-like structure with windows.

Dormer conversions are slightly more expensive than Velux conversions due to the additional structural work involved. Costs typically range from £20,000 to £40,000 depending on the size and complexity of the dormer.

Hip-to-Gable loft conversion:

Hip-to-Gable loft conversions involve extending the sloping “hip” roof to create a vertical “gable” end. This type of conversion is common in properties with hipped roofs.

Hip-to-Gable conversions can vary in cost depending on the size of the loft and the extent of the structural alterations required. Costs typically range from £25,000 to £45,000.

Mansard loft conversion:

Mansard loft conversions involve significant alterations to the roof structure, creating a flat-roofed box-like extension with steeply sloping sides. This type of conversion often provides the maximum amount of additional floor space.

Mansard conversions are typically the most expensive option due to the extensive structural work involved. Costs can vary greatly depending on the size of the loft and the design specifications but generally range from £40,000 to £70,000 or more.

It’s important for homeowners to carefully consider their needs, budget, and property constraints when choosing the type of loft conversion. 

Cost of jobs


To comprehend the financial landscape of a small loft conversion, it’s essential to analyse the costs of key jobs required for the project. Here’s a table summarising the estimated costs for essential tasks:

Job descriptionAverage cost (£)
Scaffolding£500 – £1,500
Alterations to the roof structure£1,000 – £3,000
Adding a staircase£1,500 – £3,500
Insulation£500 – £1,000
Electrical Wiring and Lighting£800 – £1,500
Plumbing£1,000 – £2,500
Windows and skylights£1,500 – £3,000
Flooring£800 – £1,500
Plastering and finishing£1,000 – £2,000
Painting and decorating£500 – £1,000
Building Regulations Compliance£500 – £1,000
Note: The costs provided above are estimates and can vary based on factors such as location, complexity of the job, materials used, and contractor rates.

Cost of materials

Here’s a breakdown of the costs of various materials commonly used in small loft conversions, presented in a table format:

MaterialCost per square meter (£)
Roof Tiles£20 – £50
Insulation£10 – £20
Flooring (Laminate)£15 – £30
Flooring (Carpet)£20 – £40
Roof Windows£300 – £800
Electrical Fixtures£20 – £50 per fixture
Plumbing Fixtures£100 – £300 per fixture
Plasterboard£5 – £10
Timber£10 – £30 per length
Paint£10 – £30 per litre
Skirting Boards£5 – £15 per meter
Doors£50 – £200 each
These costs are approximate and can vary depending on factors such as the quality of materials, brand, location, and any additional features or specifications required.

Hidden and additional costs

Undertaking a small loft conversion can be an exciting project, but it’s essential to be aware of potential hidden costs that may arise along the way. Despite careful planning and budgeting, unforeseen challenges and additional expenses can crop up during the construction process. Here are some common hidden costs to consider:

  • Structural repairs: Once construction begins, contractors may discover underlying structural issues such as rot, decay, or inadequate support. Addressing these issues may require additional materials, labour, and time, leading to unexpected expenses.
  • Unforeseen issues: As construction progresses, unforeseen issues may arise, such as hidden wiring or plumbing problems, mould or dampness, or unexpected obstacles within the walls or ceiling. Dealing with these issues can result in unplanned expenditures to rectify and ensure the safety and integrity of the conversion.
  • Permit costs: Depending on the scope of the conversion and local regulations, additional permits or approvals may be required for specific renovations, such as adding windows, altering roof structures, or installing plumbing fixtures. Obtaining these permits can incur fees and administrative costs that may not have been initially budgeted for.
  • Design changes: Homeowners may decide to make design changes or upgrades during the construction process, such as choosing higher-end finishes, altering room layouts, or adding additional features. While these changes can enhance the final result, they can also increase costs beyond the original budget.
  • Professional fees: Engaging professionals such as structural engineers, architects, or surveyors may be necessary to assess the feasibility of the conversion, obtain permits, or address unforeseen issues. These professional services come with associated fees that should be factored into the overall project budget.
  • Waste removal: Demolition and construction generate waste materials that need to be disposed of properly. The cost of waste removal, skip hire, or recycling services should be considered to ensure a clean and safe worksite throughout the project.
  • Contingency fund: Despite thorough planning, it’s challenging to anticipate every possible expense or complication that may arise during a loft conversion. Allocating a contingency fund of around 10-15% of the total project cost can provide a financial buffer to cover unexpected costs and ensure the project stays on track.

By being mindful of these potential hidden costs and incorporating them into the project budget from the outset, you can better prepare for the financial aspects of their small loft conversion and minimize the risk of budget overruns and delays.

How to reduce small loft conversion cost in the UK

cost of small loft conversion.

Reducing costs on a small loft conversion project in the UK requires careful planning, resourcefulness, and strategic decision-making. Here are top 10 tips and strategies to help you minimise expenses while still achieving their desired outcome:

Thorough planning and research:

Start by thoroughly planning the project and researching all available options. Understand the scope of work, required materials, and potential challenges to anticipate. Having a clear plan in place will help avoid costly mistakes and changes during construction.

Maximise existing space:

Make the most of the existing loft space without the need for major structural alterations. Consider simple conversions, such as adding roof windows (Velux), to create a bright and airy living area without the expense of dormers or extensions.

Opt for sustainable solutions:

Investing in sustainable and eco-friendly materials can offer long-term cost savings and environmental benefits. Consider using recycled or reclaimed materials where possible, such as reclaimed timber for flooring or recycled glass for windows. Additionally, prioritise energy-efficient insulation materials to reduce heat loss and energy consumption over time.

DIY where feasible:

Take on certain tasks yourself, if you have the skills and knowledge, to save on labour costs. Simple tasks like painting, demolition, or minor carpentry work can often be done by homeowners with the right tools and guidance.

Obtain multiple quotes:

Shop around and obtain quotes from multiple contractors and suppliers to ensure competitive pricing. Be sure to compare not only the cost but also the quality of materials and services offered.

Consider off-peak times:

Schedule the construction work during off-peak times if possible, as some contractors may offer lower rates during quieter periods. However, be mindful of potential delays due to weather conditions or availability of skilled labour.

Reuse existing fixtures and fittings:

Salvage and reuse existing fixtures and fittings, such as doors, windows, or plumbing fixtures, to reduce the need for purchasing new items. Refurbishing or repurposing existing materials can add character to the space while saving on costs.

Prioritise essential features:

Focus on essential features and prioritise your needs to avoid overspending on unnecessary luxuries. Allocate the budget towards elements that will add the most value and functionality to the space, such as insulation, heating systems, and structural integrity.

Explore financing options:

Investigate financing options, such as low-interest loans or government grants for energy-efficient home improvements, to help offset the upfront costs of the conversion.

Regular maintenance:

Once the conversion is complete, maintain the space regularly to prevent costly repairs and ensure its longevity. Address any issues promptly to avoid them escalating into larger problems down the line.

By implementing these cost-saving strategies and prioritising sustainability, you can achieve a small loft conversion in the UK that meets their needs while staying within budget and minimising environmental impact.

Ready to explore your options? Request quotes from our trusted network of professionals and kickstart your project with confidence!

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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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