James Elston
Published February 24, 2025
Last Updated on March 28, 2025
Contents
- 1 How Much Do Dormer Windows Cost?
How Much Do Dormer Windows Cost?
Dormer windows are a popular addition for UK homeowners and landlords looking to enhance their property’s space, light, and value. Understanding the costs associated with dormer window installation is crucial for effective budgeting and planning.
This guide delves into the factors influencing dormer window costs, provides detailed pricing tables, and offers insights to help you make informed decisions.
What Are the Average Costs of Dormer Windows in the UK
When considering the addition of a dormer window, it’s essential to understand the range of costs you may encounter. Dormer window prices vary depending on several factors, including the size, design, materials used, and the complexity of the installation.
On average, homeowners can expect to spend anywhere from £1,000 to £5,000 or more, depending on their specific needs.
The table below outlines the average costs for various types of dormer window installations, giving you a clearer idea of what to expect when planning your project.
| Dormer Type | Description | Average Cost (GBP) |
|---|---|---|
| Full Dormer Conversion | 2 large wooden frame windows | £4,500 |
| Side Dormer Conversion | 1 small uPVC window | £1,000 |
| L-Shaped Dormer Conversion | 3 small uPVC windows | £3,000 |
| Rear Flat Roof Dormer Conversion | 2 uPVC windows | £2,500 |
| Rear Gable Dormer | 1 uPVC window | £1,000 |
| Rear Hipped Dormer | 1 uPVC window | £1,000 |
| Scaffolding for Installation | Necessary for safe access | £1,000 |
How Much to Add a Dormer to an Existing Loft Conversion in the UK?
If you’re looking to enhance your existing loft conversion with a dormer, it’s important to understand that adding a dormer window to an already converted loft can be a more cost-effective option compared to installing one from scratch.
The average cost of adding a dormer to an existing loft conversion typically ranges from £2,500 to £6,000, but this can vary significantly based on various factors such as the size, type, planning permissions, complexity of the installation and design of the dormer, as well as the structural work needed to integrate it with your current loft space.
Factors Influencing Dormer Window Costs
Several factors affect the overall cost of installing a dormer window:
Size and Complexity
Larger and more complex designs require more materials and labour, increasing costs.
Materials Used
The choice between uPVC, timber, or aluminium frames impacts both aesthetics and price.
Type of Dormer Windows
The type of dormer window you choose plays a significant role in determining the overall cost of installation. Different dormer styles vary in terms of design complexity, materials required, and the level of work involved.
Here’s a breakdown of the most common types of dormers, their characteristics, and the types of properties they suit best:
1. Hipped Dormer
A hipped dormer features a roof with all sides sloping downwards towards the walls, creating a more compact, pyramid-like shape. This style is often chosen for its aesthetic appeal and its ability to blend seamlessly with various roof styles.
It is ideal for properties with a traditional, symmetrical roof structure, particularly detached and semi-detached homes.
- Best For: Period properties, detached houses, and homes with a symmetrical or hipped roof design.
- Average Price: £1,000 – £2,500
2. Rear Flat Roof Dormer Conversion
A rear flat roof dormer features a simple, flat roof that extends from the rear of your property, creating additional headspace and natural light. This style is the most affordable and commonly used when space is needed in a loft conversion.
It’s suitable for homes that don’t have strict aesthetic restrictions, like those in urban or suburban settings.
- Best For: Terraced homes, semi-detached properties, and those with limited roof height.
- Average Price: £2,000 – £3,500
3. L-Shaped Dormer Conversion
An L-shaped dormer combines two dormer sections at a 90-degree angle, forming an “L” shape. This style provides more usable space than a simple dormer, and it’s often used when a larger area is required in the loft.
It’s best suited for properties with a larger roof space, such as end-of-terrace houses or larger semi-detached homes.
- Best For: Larger homes, particularly semi-detached or end-of-terrace properties with expansive roof spaces.
- Average Price: £3,000 – £5,000
4. Gable Dormer
A gable dormer features a triangular roof with a vertical front, creating a more spacious and airy feel in the loft area. It’s often seen in homes with a more traditional architectural style.
The gable dormer’s sharp angles and unique appearance make it a popular choice for enhancing a property’s curb appeal. It’s most suitable for homes with pitched roofs, like cottages or detached homes.
- Best For: Homes with a pitched roof, such as cottages, detached houses, and bungalows.
- Average Price: £1,500 – £3,000
Property Type
The type of property you own can significantly influence the cost of installing a dormer window. Older properties or those with unusual roof structures may require additional modifications to accommodate the dormer, which can increase both time and labour costs.
For example, listed buildings or properties in conservation areas may require special planning permissions or adjustments to maintain architectural integrity. On the other hand, modern properties with standard roof designs are often easier and less costly to modify.
- Best For: Traditional or period homes may need extra care, while newer properties are generally less complex and more affordable for dormer installation.
Scaffolding
Scaffolding is essential for safely accessing the roof during dormer window installation, particularly on multi-story homes. The cost of scaffolding can vary depending on the height of your property and the duration of the project.
For example, installing a dormer on a three-storey house will likely require more scaffolding and result in higher costs compared to a bungalow. In general, scaffolding can add anywhere from £500 to £1,500 to the overall cost, depending on the scale of the project.
- Impact on Cost: For high or large properties, scaffolding adds a significant portion to the total cost of dormer window installation.
Labour Costs
Labour costs are another key factor in determining the price of dormer window installation. Skilled tradespeople, such as roofers, carpenters, and window fitters, are required for the installation. The complexity of the dormer design, as well as regional variations in labour rates, can influence the total labour cost.
For example, labour rates in London or the South East are generally higher than in other parts of the UK. The overall duration of the project, including preparation and finishing, will also contribute to the labour cost.
- Impact on Cost: Larger, more complex dormer windows with intricate designs or additional structural work will require more labour, increasing the cost.
Are Dormer Windows Worth It?
When considering a dormer window for your property, one of the key questions to ask is whether the investment is worth the cost. Dormer windows can offer a range of benefits, including increased natural light, better ventilation, and the ability to maximise headspace in your loft or attic.
However, like any home improvement project, there are pros and cons to consider before making a decision.
Benefits of Dormer Windows
| Increased Space and Headroom | Dormer windows can transform a cramped attic or loft into a spacious, usable living area. The vertical extension of the roofline created by a dormer adds much-needed headspace, allowing for a more comfortable and practical living space. |
| Natural Light | By adding a dormer window, you allow more natural light into your loft conversion or upper floor. This can brighten up the space, making it more inviting and pleasant to live in, as well as reducing the need for artificial lighting during the day. |
| Enhanced Property Value | Adding a dormer window to your home can increase its value, particularly if it enhances the usability and aesthetic appeal of your loft or attic space. Homes with well-designed dormers tend to appeal to a broader range of potential buyers, especially those looking for extra space or character in their property. |
| Improved Ventilation | Dormer windows improve airflow and ventilation, reducing the risk of damp or condensation in upper-floor spaces. This is particularly useful for attics that may have limited ventilation. |
| Aesthetic Appeal | Dormer windows can add charm and character to your home, particularly if you opt for a more traditional design like a gable or hipped dormer. They can elevate the appearance of your roofline, making your property stand out and look more attractive from the street. |
Drawbacks of Dormer Windows
| Cost | As we’ve seen in previous sections, dormer windows can be quite expensive to install, especially when you factor in structural modifications, scaffolding, labour, and other associated costs. For homeowners on a tight budget, the cost might be a deterrent. |
| Planning Permission | Depending on the size and location of the dormer window, you may need planning permission before proceeding with the installation. This can add time and complexity to the process, especially if your property is in a conservation area or if the dormer affects the overall design of the building. |
| Potential for Structural Modifications | Installing a dormer window often involves making significant changes to the existing roof structure, which can sometimes be more complicated and costly than initially expected. For example, some properties may require additional reinforcement to support the new window and the weight of the dormer itself. |
If you need to replace other windows in your home, we offer window replacement quotes to help you find the perfect upgrade that fits both your budget and needs.
Request a Free Quote for Your Dormer Window Installation
Ready to transform your loft space with a beautiful dormer window? Contact our team of expert window installers today for a free, no-obligation quote tailored to your specific needs.
We offer professional advice, quality craftsmanship, and competitive pricing to help you achieve the perfect addition to your home.
FAQs
How long does it take to install a dormer?
The installation of a dormer window typically takes between 2 to 4 weeks, depending on the complexity of the project, the size of the dormer, and the weather conditions.
Factors such as the type of roof structure and whether it’s a simple or more advanced dormer design can also influence the timeline. It’s always best to consult with a specialist to get an accurate estimate for your specific situation.
What type of house has dormer windows?
Dormer windows are commonly found in homes with pitched roofs, particularly in properties that feature loft conversions or attic spaces. They are often seen in Victorian, Edwardian, or bungalow-style houses.
Dormers are a great way to increase natural light and headroom in an attic or upper floor, making them popular in homes looking to maximize space without extending the building’s footprint.
Do I need permission for a dormer window?
In the UK, whether you need permission for a dormer window depends on the scope of the project. If the dormer is within the allowed limits of permitted development (for example, it’s not too large, and it’s not facing a highway), you might not need planning permission.
However, if the dormer affects the structure or appearance of the building significantly, or if it’s in a conservation area, listed building, or an area with special restrictions, you will likely need to apply for planning permission.
Always check with your local council to ensure you’re complying with all regulations.
James Elston
Boiler Expert
James Elston is the top boiler replacement and heating expert at Eco Happy. He has over 20 years of experience in the industry, focusing on Gas Safe boiler installations and offering home-heating and energy-saving solutions to homeowners across the UK. From sourcing the most energy-efficient combi boiler to providing specialist heating advice, James ensures that Eco Happy maintains the highest standards and best customer service.