Dormer Loft Conversion Cost 2024

New loft conversions in London have long been the most popular choice for homeowners who want to add value and flexibility to their houses. Of all types of conversions, the dormer is the most popular alternative. You may dream of having the addition of a bathroom, an office, or the possibility of a bedroom with an ensuite. Well, a Dormer loft conversion in London could make your dreams come true.


At Fittra, we are aware of the potential that lies inside that unoccupied attic. Making it a lively living space in your house increases your property’s value as well as enhances your home’s enjoyment. If you are thinking about this kind of work, we suggest reading this article. This Dormer Loft Conversion Guide will break down the dormer loft conversion cost and help you determine whether it is a conversion you want.

dormer loft conversion cost
cost of dormer loft conversion


Understanding the Popularity and Benefits of Dormer Loft Conversions

Universal appeal: The range of dormer converts is unparalleled. Do you require an additional bathroom or bedroom with more space or an expansive space for your home office? The conversions are able to be customised to fit a wide range of requirements and are a preferred option for a lot of homeowners.


Value boost: When you do this, you do not just add an area to your house, but you also boost the value. Dormer loft conversions could increase the value of your house between 10 and 20 per cent. Its potential to create greater value for your home is a compelling idea to consider for the near future.


Accessibility for the Majority: Dormer conversions sometimes fall under permitted development.’ It means that for many residences, there is no need to obtain planning approval.


Overview of Dormer Loft Conversion Costs in the UK

How Much Does a Dormer Loft Conversion Cost?

In 2024, loft conversions that are small in size (a basic loft conversion) prices range between £2,000 and £7,000. Medium dormer conversions cost around £30,000 to £60,000. The cost of large-scale conversions ranges upwards of £40,000 to £130,000+, depending on the project’s details.

how much does a dormer cost
how much is a dormer loft conversion

Average Cost of Dormer Loft Conversion

The standard dormer loft addition costs between £32,000 and £60,000+. The option of an L-shaped dormer loft extension could result in costs that range from £60,000-£130,000, depending on the size and difficulty of the conversion.

Detailed Cost Breakdown

Below is an easy cost breakdown to convert your loft:

Material Costs

Loft Conversion Windows:

Size (cm)

Average Cost

50 x 50

£150 – £200

100 x 100

£200 – £250

120 x 120

£250 – £300

Loft Conversion Flooring:


Average Cost per m2


£4 – £40


£7 – £20


£10 – £60


£10 – £70


Loft Conversion Insulation:


Average Cost per m2


£5 – £15


£12 – £27


£15 – £25


Loft Conversion Stairs:


Average Cost

Fixed ladder with Bannister

£150 – £400

Alternating Treads

£350 – £750


£1,000 – £1,500


£1,000 – £1,200


£3,000 – £10,000


General Building Materials:


Average Cost


£300 – £600

Decorating materials

£800 – £1,600


£4,500 – £6,000

Structural beams, joists, and masonry

£1,500 – £4,000

Built-in Storage

£1,500 – £10,000


Labour Costs

Costs of labour and timings differ but usually consist of three or four individuals on-site at one time.


Average Cost per Hour


£20 – £35


£20 – £40


£35 – £45


£50 – £120


£30 – £50


£20 – £50


Additional Expenses

Think about these costs in the creation of a budget for your loft conversion: 



Bathroom fittings

£4,500 to £6,000


£800 to £900/week

Skip hire


Party wall agreement



£1,000 to £1,500

This thorough breakdown will give you a better idea of what to anticipate in terms of dormer extension cost in the UK. 

Key Factors Influencing the Cost of a Dormer Loft Conversion

The financial aspects of the dormer loft conversion will require a thorough examination of the numerous factors that affect it. The factors mentioned above can dramatically influence the typical cost overall, which is why it vital for homeowners to understand the impact of these factors. Let us explore these factors of a dormer loft: 

Size and Complexity

dormer cost
dormer extension cost

The size and type of your loft conversion affects prices. Bigger and more complicated conversions will likely require more significant funds.

  • More space requires more resources: Expanding the area will mean that construction will require more products, like lumber, insulation, and roofing.
  • Complex designs require skilled hands: Special features or unusual designs require the skills of experienced experts, which can increase the cost of labour.
  • Time of the project: The more complex projects can require more time to complete, increasing the cost of labour as well as disrupting your day-to-day routine.


The sum of all these factors shows how the scope of the project has a major impact on its budget. Simply put, a simple conversion will have a lower cost as opposed to a complex, custom style.

Location Variations

Your location could drastically affect the costs of your loft conversion. The factors that affect your cost of labour, material prices, and local laws each play a key role.


  • Diverse labour costs: Cities, particularly those with a higher cost of living, are more likely to have higher labour costs.
  • Variable prices for materials: Local availability may cause the cost of material to differ by region.
  • Costs of regulatory compliance: The requirement to obtain permits as well as adherence to local building codes could result in costs.


Understanding these differences in regional settings is vital. Similar loft conversions could cost differently depending on the geographical location.

how much for a dormer loft conversion
cost of dormer extension

Quality of Materials

The choice of material affects the design and lifespan of the loft conversion. This has a significant effect on your budget.


  • The best materials have costs: Premium material can improve the design and longevity of the conversion, but they will additionally increase your overall cost.
  • It is possible to save on energy costs: Over the long term, investing in windows and insulation can result in longer-term savings in energy costs regardless of the higher cost.
  • The right balance to strike is essential: It is crucial to find a way to manage quality and costs so that the final product is in line with your standards of aesthetic as well as your budgetary constraints.


When paying close attention to these crucial aspects, homeowners will have a greater knowledge of the factors that affect the price of converting their loft to a dormer. The knowledge gained will allow you to take informed choices that are tailored to the needs of your family and budget.

Detailed Guide to Dormer Loft Conversions and Their Costs

Dormer loft conversions are a good option, but no “one-size-fits-all” type exists. However, there are several options with different levels of complexity and cost.

Standard Dormer Loft Conversion

Dormer loft conversion (or a flat roof dormer) is renowned for its ease of use and affordability. When you extend vertically off the roof’s slope this creates more room as well as headroom. It is ideal for letting in sunlight through windows in the dormer and is less difficult to construct. A standard dormer is the best option for homeowners seeking to increase their home without requiring extensive modifications to the structure, with prices that range from £2,000 to £30,000.

how much dormer loft conversion

Double Dormer Loft Conversion

Unlike the traditional dormer, the double dormers extend across two sides. It doubles the benefit of additional space and light. This design is ideal for those who want to maximise their loft’s possibilities, which allows to create multiple bedrooms or an expansive master suite. While it is an increased cost because of the larger size of construction, the cost between £10,000 and £30,000 can increase the home’s worth and the usable space.

L-Shaped Dormer Loft Conversion

The loft conversion of the L-shaped dormer also known as a dog leg dormer has two dormers that intersect to form an L-shape. This intricate design is designed for houses that have roofs with L-shaped shapes, providing the most living space. Perfect for adding bedrooms or a bathroom with an L-shaped roof, this dormer offers an extensive solution to make use of the footprint of your house. Due to its difficulty, it can cost more than £130,000, yet the increase in the space and property value could be significant.

Gable-Fronted Dormer

Gable-fronted dormers, also known as dog-house dormer extends the gable wall and connects to the roof’s ridgeline. The architectural enhancement adds visual appeal to the house and will require substantial structural work, which makes it more costly. The cost ranges between £60,000 and more than £130,000 this option provides both style and space for people who want to create a unique house.

Hip-to-Gable Loft Conversion

If you want a more integrated and pleasing appearance, the hip-to-gable loft conversion has slopes on all three sides and blends seamlessly into the existing roof. Most often, it is chosen because of its design the dormer is ideal for homes with larger rooms, but it can provide less interior space than some dormers. Its complexity makes it a larger price category which ranges from about upwards of £60,000 and up to more than £130,000. Homeowners who are keen on their house’s exterior design are likely to find a high-pitched roof dormer a stylish alternative despite the expense.

cost of a dormer

Mansard Loft Conversions

A Mansard loft conversion involves altering the structure of your home’s roof to extend the sloping part almost vertically, typically to 72 degrees. This type of conversion creates a significant amount of additional living space, often enough for multiple rooms. The cost for a Mansard loft conversion starts at around £18,000, with the final price depending on the project’s complexity, size, and finishing choices.

Step-by-Step Process of a Dormer Loft Conversion

Initial Consultation and Design

The process of converting a dormer loft starts with a discussion to talk about what you would like to do with your loft. Then, in this discussion, you discuss your plans and the way you intend to utilise the newly created space. It is crucial for us to know what you are searching for so that we can create it.

how much does a dormer loft conversion cost
dormer loft conversion cost 2024

After our discussion, the design team gets working. It usually takes 2 to 4 weeks. In this period, we develop a thorough design that makes the most of the light and space available and ensures the space can be used for the purpose you want. We will also handle all the paperwork required at this phase, such as obtaining permits for planning and ensuring that all the plans we make are governed to be built according to local rules.


This planning stage is vital as it ensures we are prepared to build the structure without any issues. Our goal is to make everything simple and clear, so that everyone is aware of the process every step. At the end of four weeks, we will be able to plan everything out and prepared making sure that the building process is smooth and completed in time. So, we can transform your loft into amazing new space, without any unnecessary problems.

Week-by-Week Breakdown of Construction

The loft conversion is a challenging task. However, when you have the proper strategy and planning, it is accomplished without causing disturbance to your life. 


This is a common timetable for a loft dormer conversion when the weather is ideal:

  • Week 1: We start off the construction by building scaffolding and then bringing the necessary materials to the location. The roof will be opened this week and is laying foundation for the exciting changes to come.
  • Week 2: Our attention turns towards the roof, especially in the event that structural modifications are required. There is a possibility of adding additional assistance at this point. The installation of windows for roof lights or the building of the dormer will take place when it is appropriate.
dormer conversion cost
  • Week 3: The main focus is to complete the exterior elements, which includes roofing work including replacing tiles and making sure that the roof is finished. Roof insulation is used to make sure your new home is cozy and effective. In the loft, preparation begins with electrical and plumbing installations.
  • Week 4: All remaining windows have been installed, and the flooring has been laid to ensure adequate venting. The board is laid, then we begin building any walls inside that we require.
  • Week 5: Now is the time to put up the stairs and join your loft in with your house. If you are planning to add a bathroom, this is the ideal time to begin the installation. The electrical setups are finished, and we complete tasks like installing doors, plaster skimming and connecting skirting boards.
  • Week 6: The final week will be spent completing the remaining work. If the package you purchased involves decorating, then we will handle this now. This project will end with the removal of scaffolding and leaving you with a renovated loft that is ready to be enjoyed.

This plan is the ideal situation, with the goal of the least disruption and maximum efficiency.

Financial and Legal Considerations for Your Loft Conversion

Planning Permission and Building Regulations

Understanding the legal and financial aspects of converting your loft is crucial to a successful project. One of the initial steps is to determine if you require permission to plan your project.

dormer cost uk
average cost of dormer loft conversion

Typically, the addition of dormer windows on an exterior of the home is subject to approval by the council in question due to changes in the structure’s exterior look. However, windows that are installed at the rear of the home typically qualify as permitted developments, which means they do not require planning permission. It is important to remember that rules can differ according to your area, so consulting with the local authorities is recommended.  


Beyond the planning approval, the project needs to comply with building regulations to ensure that the construction is secure and complies with current standards for construction. The regulations address a variety of aspects, ranging including structural integrity and safety in the event of fire, and costs for compliance can vary from £400 up to £800. The precise cost is contingent on the size and complexity of the loft conversion.

If you share walls with neighbouring houses, signing a Party Wall Agreement is necessary. The legal agreement will require you to get your neighbours’ permission before building on shared walls. Cost for hiring a surveyor the purpose is different but ranges between £150 and 200 per hour. In addition to the cost of hiring a surveyor as well as the costs of signing an agreement for a Party Wall Agreement can total approximately £1000.


In order to organise the required documents, it can take time. It all depends on the experts their availability as well as the project’s scope, the preparatory period can last for some weeks. This is a crucial time that will establish the base to your loft conversion making sure that safety and environmental specifications are in place before construction can begin, so be sure that you meet the requirements.

loft dormer cost
dormer extension cost uk

Ways to Finance Your Dormer Loft Conversion

Personal Loans

A personal loan offered by an institution like a bank is a popular option. The type of loan you get is not a requirement to secure your home or other property to secure it. With attractive interest rates and a range of times for repayments, which range from one to five years, these loans provide an option to fund small-scale changes. They are fairly simple to qualify for when you have an excellent credit score, making them an ideal alternative for fast financing.

Home Loans

The homeowners might want to consider tapping to the equity of their house by obtaining secured loans or a second mortgage. This option allows borrowing from the equity you have accrued in your house, which could grant access to greater amounts of cash with an extended repayment period. But the risks are much higher since your home acts as collateral. You must carefully consider this possibility to minimise the chance of losing your house if the repayments are not manageable.

loft conversion dormer cost
cost of loft conversion with dormer

Other Financing Options

A variety of alternative funding routes may be explored as well:

  • Savings: Using your savings can be the simplest and most efficient approach to avoid the necessity to borrow.
  • Overdrafts: Ideal to cover smaller costs, particularly if you benefit from an interest-free period. But the higher rates will increase after the first offer time.
  • Credit cards: A credit card can solve immediate needs, but typically with higher limits and lower interest rates.
  • Remortgaging: Borrowing against the house’s worth could result in an impressive amount for your project, with the benefit of a longer repayment term. You must consider all the implications of this, as well as the possibility of early repayment fees.

Assessing the Options

Before you decide on the ideal method to finance the loft conversion, look at the benefits and drawbacks of each choice. Take into consideration the interest rate, repayment term, and your finances. Assessing your financial condition, such as your credit rating as well as your income and expenditures, is vital to making an informed choice.

dormer loft conversion cost uk
how much do dormer loft conversions cost

Advantages of Opting for a Dormer Loft Conversion

If you want to enhance the living area and improve the value of your house, a dormer loft conversion can be a choice. Below, we will provide a deeper look into how this type of transformation can benefit homeowners.

Enhanced Living Space

Imagine your house being flooded with sunlight without degrading your garden’s beauty. This is the appeal of converting a loft into a dormer. It is a creative method of expanding your living space by letting the light in and creating the illusion of larger living space.


In the event that you are considering shifting due to small living spaces, think about an initial loft conversion. A loft conversion is a wonderful way to create that space without the expense and hassle of relocating. Extensions are not always the best option, particularly when it comes to protecting outdoor spaces.

loft conversion with dormer cost
dormer roof cost

Increased Property Value

The experts in the field of real estate concur that loft conversions are among the top improvement to your home that will increase its worth. In the average, you can expect a rise of between 10 and 20 percent.


Before you dive in the water, you must be aware of the market for property within your region. In the case of a home are priced at £350,000, and you have a house that costs £320,000, investing more than £30,000 for a conversion could not bring a profit. Therefore, doing a bit of research will help you budget to ensure that your conversion is secure and lucrative.

Improved Energy Efficiency

Building codes demand insulation when loft conversions are required, the initial cost of which can be repaid by improving the efficiency of your home. This can drastically reduce the cost of heating, resulting in the prospect of long-term savings.


Although the initial cost may appear daunting, the advantages of a more comfortable, energy efficient home will far exceed the expenses, resulting in this service being an excellent choice for people who want to increase their property’s value and living space.

dormer roof extension cost
how much is a dormer

Why Choose Fittra for Your Dormer Loft Conversion?

Now you understand the costs and benefits better, you might want to construct one. We at Fittra believe in the importance of every square inch. The way we approach dormer loft conversions is more than simply adding square footage. We focus on delivering value, improving living spaces, and providing satisfaction.

Expertise and Experience of Fittra

When you choose Fittra, you’re investing in a construction company that brings more than a decade of excellence in construction to your fingertips. The basis of our foundation is:

  • An extensive track record of success in construction projects, both residential as well as commercial.
  • An experienced team of experts comprising engineers, architects as well as designers.
  • The registration is through NHBC is a way to ensure that the company follows industry standards.
loft conversion with ensuite cost
dormer loft conversion with ensuite cost

When you interact with our team, we will show you how our vast knowledge enhances the project you are working on and empowers you by providing options and insights you might not have thought of.


  • We are confident in our abilities to tackle complex problems and produce the results you expect.
  • Get access to innovative solutions that improve your home’s function and appearance.
  • You can rest assured that your house is in the capable hands of a reputable professional.

Comprehensive Services Offered by Fittra

Opting to go with Fittra is opting for a seamless, well-integrated process for the dormer loft conversion. We can help you with every step of the conversion process:

  • Planning permissions guidance, to ensure that your plans follow the local rules.
  • Custom design services, translating your vision into a tangible, functional layout.
  • Complete construction solutions from foundational work all the way through the final details.


The comprehensive method means that you will get the following:

  • An organised project schedule without causing disruption to your everyday routine.
  • Styles that show your individuality and cater to your individual demands.
  • Construction that is safe and efficient that professionals supervise.
cost dormer loft conversion
average cost of loft conversion with dormer

Client-Centric Approach and Competitive Pricing

The core of Fittra’s philosophy lies in an obligation to our customers. We believe in clear communications, customised solutions, and fair pricing.


  • Free consultations to understand fully your project goal.
  • Custom-designed project management and design process to ensure that your design is entirely yours.
  • Simple, easy-to-understand plan of payment with competitive prices as well as trade discounts.

If you select Fittra, you’re not only hiring a professional; you are getting a partner who is dedicated to:

  • Ensuring that your loft conversion process is a stress-free and enjoyable procedure.
  • Designing and constructing a space that will meet the aesthetic as well as practical requirements.
  • Giving you value for your money and boosting the value of your home and the quality of your living.


Let Fittra assist you in turning your loft conversion dreams into a reality using the experience, care, and dedication you have earned.

cost of a dormer loft conversion
average cost of loft conversion with dormer

Preparing for Your Dormer Loft Conversion

It is essential to plan ahead so that loft conversions are completed easily and yield the perfect result you have always wanted. This article will guide you in selecting the right contractor and provide guidelines to manage the project efficiently.

Selecting the Right Contractor

Selecting a professional you can be confident in your home’s construction, and your vision is essential. Take these steps to make sure that you pick the right contractor:


  1. Do your research: Look for firms that specialise in construction and have knowledge of dormer loft conversions. Review their portfolios and read their reviews.
  2. Ask several contractors for quotations: Ensure they provide the project’s timelines, costs, and extent.
  3. Verify Credentials: Check their credentials, insurance, and all relevant certifications. A reliable contractor should not have any issues providing the information required.
  4. Interview contractors: It is a fantastic opportunity to assess their communication skills and their commitment to high quality.
  5. References: Make sure to request and verify references. Past clients can provide invaluable information about their experience working with the contractor.

Fittra's Checklist for a Smooth Conversion Process

To assist you in managing your dormer project, we have put together the following loft conversion checklist. Use this checklist as a reference to help keep your project in order and ensure there are no problems. 

how much is a dormer extension


Your Notes

Research local planning requirements


Finalise design and layout with the architect


Secure planning permission (if required)


Agree on a detailed quote and timeline with Fittra


Set up a regular communication schedule with your project manager


Arrange for temporary storage solutions if necessary


Confirm all material selections (e.g., fixtures, finishes)


Review and understand the payment schedule


Prepare your home for construction


Plan for any necessary accommodations during construction

how much are dormers


Recap of Dormer Loft Conversion Benefits and Costs

A dormer loft conversion offers a variety of benefits that include adding sunlight and room to your house and, most crucially, boosting its worth.

Also, we discussed the importance of making homes more energy-efficient by this process. We also stressed that the purpose is not only to extend your living space and improve your home’s ecological sustainability but also to reduce energy costs overall.


Below is a quick breakdown of a dormer conversion cost in the UK: 

  • Loft conversions to small dormers can cost anywhere from £2,000 to £7,700.
  • Medium-sized conversions can vary from £10,000 up to £30,000.
  • In the case of large-scale projects, costs could be as high as £40,000 or above £60,000 based upon the particular requirements and specifications.
how much does it cost to build a dormer uk
cost of dormer loft conversion

The advantages of pursuing the dormer conversion are obvious and convincing:

  • The universal appeal: Whether you are seeking to create an extra bedroom or, a brand-new bathroom, or even your own workspace, Dormer loft conversions provide the ability to accommodate a variety of requirements, which makes these conversions a favourite choice for homeowners.
  • Value boost: Adding value to your house with more usable space can do more than enhance your living space. It can even improve the value of your home up to 10 or 20 percent. The potential for value-added makes dormer conversions a desirable choice for an investment.
  • Accessibility for the Most: The biggest benefit of dormer conversions is that many of them are considered permitted developments, eliminating the requirement to obtain planning approval for many homes. This means it is much easier and faster for homeowners to begin their projects to convert, easing the process of transforming their properties.

Next Steps for Planning Your Conversion with Fittra

With all the essential information regarding Dormer Loft conversions, the next step is to bring the vision into reality. Fittra will be there to assist with each stage of the process. Fittra is the perfect contractor for your project, with more than a decade of expertise and a dedication to excellence, as well as a wide array of solutions.


If you are ready to start, contact us. When you are ready to begin the loft conversion project or need help, our staff will be available to offer the best guidance and help. We will be in close contact with you to make sure your plan is completed flawlessly beginning with the design phase until the final stage.

dormer loft conversion cost


Why Work With US

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at all stages

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with project manager

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liability insurance

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of works

Integrated, In-house Team Will Work On Your Project

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Benefits from our trade discounts
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£5M public & products liability
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10% only deposit payments
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Detailed cost breakdown

In the End You Will Get




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Frequently Asked Questions

What is the Average Duration of a Dormer Loft Conversion?

In general, a dormer loft conversion can take around six weeks to finish. The time can differ based on the complexity of the job and the requirements of the property. 

How Does a Dormer Loft Conversion Add Value to My Property?

It increases your property by 10 to 20 because it adds extra living space, such as bedrooms or bathrooms, making your home more appealing to the housing market. 

Do I Need Planning Permission for a Dormer Loft Conversion?

Most of the time, there is no need for the approval of a planner for a dormer loft conversion particularly when it is at an exterior part of your home. Front-facing conversions typically require approval. 

What are the unanticipated costs that are associated with the Dormer Loft Change?

Take into consideration potential costs, such as the cost of planning permissions and party wall contracts, when planning for a loft conversion. Even though they are not required in all cases, planning ahead is essential. 

Do you know of any cost differences between a rear Dormer and a side Dormer Loft Conversion?

There are some differences. An extension to the loft of a standard dormer costs between £32,000 to upwards of £60,000. If you decide to opt for an L-shaped dormer that offers more space it is possible to expect prices to range from £60,000-£130,000+. The kind of dormer ideal for your needs is determined by the type of property you live in, your budget and the desired result.

How do Dormer Loft Conversion Costs Vary for Different Property Types?

Costs for the conversion of a dormer loft can differ significantly based on the home’s type. Semi-detached, terraced, and detached houses have distinct space and structural considerations, changing the project’s scope and cost.

What are the Long-term Financial Benefits of Investing in a Dormer Loft Conversion?

A loft conversion with a dormer offers many long-term benefits of financial stability including substantial energy savings because of increased insulation and better ventilating ability. Furthermore, the improvement in the value of your home is far greater than the investment initially, making the conversion financially prudent. 

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