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How much does a loft conversion cost?

loft conversion cost
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Loft conversions have become an increasingly popular way for homeowners to expand their living space without the need to move. Whether you dream of a serene bedroom retreat, a bright and airy office, or a sy playroom for the kids, a loft conversion can add significant value to your home. However, one of the first questions that comes to mind is, “How much will it cost?”

Here, we offer you a complete guide on loft conversions and break down the costs associated with transforming your loft into a functional and stylish space.

Different types of loft conversions available

loft conversion types

Before we can fully understand loft conversion cost, we need to explore the various different types of loft conversion that are available.

Velux (roof light) conversion

Velux conversions include the addition of spacious roof windows, enabling natural light to fill the area. This approach is both cost-effective and widely favoured by homeowners, offering a simple method to transform your roof space into a vibrant and habitable zone. They are built by  simply utilising the space that already exists. Velux loft conversion cost is generally the most affordable type of conversion available.

Dormer loft conversion

Dormer conversions involve extending the current roof structure, which not only adds extra headroom and floor space but also enhances natural light within the space. This versatile style offers the flexibility to incorporate various design options, allowing for personalised and unique living spaces tailored to individual preferences.

A dormer loft conversion is built by  constructing a vertical wall and a horizontal ceiling onto an existing roof, creating additional floor space.

Dormer loft conversion cost is typically higher than that of a Velux conversion, due to it being a larger and more complex job.

Hip-to-gable loft conversion

A hip-to-gable conversion involves replacing the sloping side of a hipped roof with a vertical wall (gable). This type of conversion is more suitable for detached or semi-detached properties, as it requires ample external space. The added benefit of this conversion is that it can create more headroom and floor space compared to a dormer loft conversion.

Hip-to-gable loft conversion cost is generally higher than a dormer conversion but can be more cost-effective than a full Mansard or L-shaped conversion.

Bungalow loft conversion

Bungalow loft conversions are suitable for single-story properties, where the roof space is converted into additional living space. As bungalows have a larger footprint compared to other properties, they offer ample opportunities to create multiple rooms or even an entire floor within the loft.

Mansard loft conversion

A Mansard conversion requires the most extensive structural work, as it involves raising the party wall shared with your neighbour by at least one metre. This type of conversion maximises usable space with its nearly vertical walls and flat roof design. This type of conversion typically requires planning permission due to its extensive construction work.

Mansard loft conversion cost is typically the most expensive type of loft conversion due to its complexity and extensive structural work involved.

Although it may be the most expensive option, it creates a significant increase in living space and can add substantial value to your property.

L-shaped dormer conversion

An L-shaped dormer conversion is a combination of a dormer and Mansard conversion, resulting in an ‘L’ shaped design. This type of conversion maximises floor space and allows for more natural light to enter the room. It is often considered another one of the most expensive types of loft conversions due to its complexity. However, it can add significant value to your property and increase loft space considerably.

Average cost of a loft conversion in the UK by location

loft conversion cost in uk

The cost of a loft conversion varies widely based on several factors including location, size, type of conversion, and the quality of materials used.

On average, a basic loft conversion cost is anywhere between £60,000 and £85,000.

However, it’s important to take into account the many variables and additional expenditure outside of labour and materials that can influence your loft conversion costs.

Below is a national average of loft conversion based on style and geographic location within the UK.

Style/LocationLondonSouth EastSouth WestNorthEast MidlandsWest Midlands
Velux (roof light)£18,200£17,500£18,500£20,000£19,000£17,000
Main dormer loft conversion£57,000£55,500£57,000£66,000£58,500£50,000
Hip to gable loft conversion£55,000£67,400£77,700£48,000£57,500£54,000
L-shaped loft conversion£62,500£65,000£63,500£68,000£59,000£57,000

Once again, these loft conversion prices are averages and only relate to labour and materials. We will break down some further associated costs below, but the best way to get the most accurate price for your loft conversion is to get in touch with a loft conversion company so you can discuss your exact requirements and receive a tailored quote.

The main factors that affect cost

  • Location: Costs are typically higher in major cities compared to rural areas due to the higher cost of living and labour.
  • Size of Conversion: Larger conversions require more materials and labour, increasing the overall cost.
  • Type of Loft Conversion: From simple Velux conversions to more elaborate Dormer and Mansard conversions, the type you choose has a significant impact on price.
  • Quality of Build and Materials: Opting for high-quality finishes and materials will naturally increase the cost.

Aspects that make up the cost of loft conversion

average costs for loft conversions


Design fees can range from £2,400 to £3,200 (4-7% of your total costs) depending on the complexity of your project.

Admin fees and building regulation fees

Planning permission will sometimes be necessary and fees for building regulations must be factored in, which can add several hundred pounds to your budget. You should expect additional costs if there are any party wall agreement issues with your neighbours.

Structural engineers and surveyors

Necessary for ensuring the structural integrity of your conversion, with costs varying based on the scope of work. Usually between £600 and £1,100 for structural engineers and £500 – £1,500 for surveyors.

Labour and materials

Labour and the price of construction materials can greatly affect the overall price, and make up 40-50% of the total cost. Therefore, It’s crucial to get multiple quotes to find the best balance between cost and quality.

Average costs for key components of loft extensions

cost of your loft conversion

Windows and glazing

Expect to pay between £900 – £1,200 for Velux windows and £4,500 -£6,000 per window on a dormer loft conversion.


The cost can vary widely, but on average, roofing materials and associated works can cost between £3,250 and £7,000.


Depending on the type of flooring chosen, costs can range from £20 to £100 per square metre.

Stairs for loft extensions

An essential yet often overlooked expense. Loft conversion stairs cost between £1,200 and £9,000.


Proper insulation is critical for making the space comfortable. Expect to pay around £10 to £40 per square metre of insulation depending on the type you go for.

Other costs to consider

Don’t overlook the potential need for:

  • Electrical and plumbing work: Necessary if you plan to include a bathroom or kitchen.
  • Decor and finishing touches: Painting, lighting, and decoration can also add to the cost.

How to save money on your loft extension

  1. Be clear on your requirements: The more precise you can be about what you want, the more accurately your contractor can quote.
  2. Choose your materials wisely: Opting for cost-effective materials can save thousands without compromising on style.
  3. Do some of the work yourself: If you’re handy, doing some of the painting or finishing work can reduce costs.
  4. Get multiple quotes: It’s essential to get quotes from multiple contractors to compare prices and find the best deal.


Q: Does a loft conversion add value and which type adds the most?

A: Every loft conversion will add value to your home as you’re turning the previously unused loft space into a functional room, thus increasing the appeal and liveability of the property.

The type of conversion that adds the most value depends on your property and its location. However, Mansard and L-shaped dormer conversions are often considered to add the most value due to their increased living space.

Q: How long does a loft conversion take to complete?

A: The time it takes to complete a loft conversion depends on various factors such as the type of conversion, size, and complexity. On average, expect a loft conversion to take anywhere from 4-8 weeks.

Q: Do I need planning permission for my loft conversion?

A: For most loft conversions, planning permission is not needed for a standard loft conversion as it falls under permitted development rights. However, if you live in a conservation area, your property is listed or the loft extension style you’ve chosen entails extensive work to your property, you may need planning permission. It’s always best to check with your local planning authority or see if the loft conversion company themselves can advise you.


A loft conversion is a significant investment but one that can not only improve your quality of life but also increase the value of your home. Understanding the costs involved and planning accordingly can help ensure that your loft conversion project is both successful and cost-effective.

While they can be a significant investment, proper research and planning can help save money without sacrificing quality. Factors such as location, size, and type of conversion all play a role in the cost of your loft extension. With proper planning and budgeting, you can turn your unused loft space into a valuable addition to your home.

Ready for your free quote?

For those interested in exploring loft conversion options, Castlepoint Construction offers comprehensive design and installation services tailored to meet your specific needs and budget. Contact us today to find out how we can help turn your loft conversion dreams into reality.

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