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A Brief Guide to Dormer Loft Conversions

Updated: Dec 19, 2023


Unused space — whether a spare bedroom that’s never used or an attic that has been collecting dust for as long as you can remember — can be put into efficient use with a dormer conversion in both traditional and contemporary homes alike.   From how the construction is done to the required planning permissions and pros & cons, we’ve rounded up all the details you’ll need to get started with a dormer conversion.

Unused space — whether a spare bedroom that’s never used or an attic that has been collecting dust for as long as you can remember — can be put into efficient use with a dormer conversion in both traditional and contemporary homes alike.


From how the construction is done to the required planning permissions and pros & cons, we’ve rounded up all the details you’ll need to get started with a dormer conversion. Once you have gathered your ideas, it's always best to share them with a professional to receive feedback and valuable tips. Book a chat with one of our Structural Engineering Gurus for step-by-step guidance for your dormer conversion.


What is a Dormer Loft Conversion?


"A dormer loft conversion is when a pitched roof is converted into a box shaped structure, creating walls that sit at a 90 degree angle to the floor," states Robert Wood, Director of Simply Loft.   To put it out simply, a dormer conversion is done by adding a tiny structure called a ‘dormer’ to the top of your house’s roof. This helps expand the headspace and floorspace, along with creating room for installing windows that provide sufficient natural light to make the area feel spacious.

"A dormer loft conversion is when a pitched roof is converted into a box-shaped structure, creating walls that sit at a 90-degree angle to the floor," states Robert Wood, Director of Simply Loft.


A dormer loft conversion involves adding a protruding structure, called a "dormer", to the existing roof, expanding both headspace and floorspace. This extension creates room for windows, allowing ample natural light to make the space feel more open.


The various dormer styles, such as shed, gable, and hip dormers, cater to different architectural preferences and roof designs. Beyond aesthetic benefits, dormers significantly enhance the functionality of the loft, providing space for bedrooms, bathrooms, or home offices. Compliance with local planning regulations and building standards is crucial, and the construction process involves cutting an opening, framing the dormer, and seamlessly integrating it with the roofline.


What are the Pros and Cons of a Dormer Conversion?


Pros Maximises headroom Windows and doors maximise natural light and airflow  Increases living space  Boosts the value of your home Cons  Is expensive  Is a complicated process and involves hiring and hiring a contractor Requires structural changes to a roof

Pros

Cons


What are the Types of Dormer Conversions?


There are four types of dormer loft conversions, each with its unique characteristics.


Flat-Roof Dormer Loft Conversion


Flat-Roof Dormer Loft Conversion:

  • One of the most popular styles

  • Add lots of extra useable space

  • Can be full-width or single

  • Allows in plenty of light

  • A small balcony and French doors are sometimes added


Shed Roof Dormer Loft Conversion


Shed Roof Dormer Loft Conversion:

  • Similar to flat-roof dormers

  • Made of a roof sloping down at a slight angle

  • Good choice for houses with a gable roof


L-Shaped Dormer Loft Conversion


L-Shaped Dormer Loft Conversion:

Credit: Houzz


  • Combines two dormers to create an L-shape

  • Common in semi-detached and Victorian terraced houses


Gable (or Pitched Roof) Dormer Loft Conversion


Gable (or Pitched Roof) Dormer Loft Conversion:

  • Normally located at the rear of the house

  • Made of full-height glazing

  • Expensive compared to flat-roofed dormer conversions


How to Know if a Dormer Conversion is Fit for Your Home?


"The main ‘pinch-point’ with loft conversions can be summed up in a single word — headroom," suggests Ian Rock, a chartered surveyor. Although the normal height for a traditional roof is 2.4 to 2.6 metres, the available space shrinks when a new floor structure is added, and rafters are lined with insulation. Therefore, to see whether your loft is up to the mark for a dormer conversion, stand beneath the highest point of the roof (typically the central point of the loft) and measure whether there is a minimum of 2.8m of clear vertical space.   Pro Tip: If the height is lower than the optimal level, you could consider stealing some space from the rooms underneath by lowering their ceilings. However, this will add to the costs and the disruption incurred, so it is better to view your budget beforehand.

"The main ‘pinch-point’ with loft conversions can be summed up in a single word — headroom," suggests Ian Rock, a chartered surveyor. Although the normal height for a traditional roof is 2.4 to 2.6 metres, the available space shrinks when a new floor structure is added, and rafters are lined with insulation. Therefore, to see whether your loft is up to the mark for a dormer conversion, stand beneath the highest point of the roof (typically the central point of the loft) and measure whether there is a minimum of 2.8m of clear vertical space.


Pro Tip: If the height is lower than the optimal level, you could consider stealing some space from the rooms underneath by lowering their ceilings. However, this will add to the costs and the disruption incurred, so it is better to view your budget beforehand.


How to Know if A Dormer Conversion is Fit for You?


To decide the answer, ask yourself the following questions:

  • Is your home made of low ceilings? A dormer conversion can raise the height.

  • How much will it cost? This depends on the location you choose and the contractor you work with.

  • Where will the loft stairs go? If you need to sacrifice space from an existing bedroom, it may not be worth it.

  • Are you comfortable with the process? A dormer conversion might disrupt your daily routine for an extended period.

  • Does your attic have enough space for a bedroom, bathroom, or lounge? If not, consider some other type of conversion.

  • Why do you need a dormer? The type of dormer you opt for varies according to your lifestyle requirements.


Do You Need Planning Permissions for a Dormer Conversion?


"In most cases, dormer loft conversions don’t need planning permission as long as they stay within the permitted development (PD) rules for your type of house," says Robert Wood, Director of Simply Loft.   Since most dormer loft conversions are deemed permitted development, you will only need planning permissions if your project exceeds certain conditions and limits, such as: You live in a conservation area or it is a listed building.  The height of the dormer conversion exceeds the height of the original roof.  The conversion affects neighbours through overshadowing or overlooking.  Bats reside in your loft. As a protected species, you need permission before disturbing their habitat.  Pro Tip: It is always best to consult an expert before initiating a project. You can chat with one of our chartered architects for expert advice and personalised guidance.

"In most cases, dormer loft conversions don’t need planning permission as long as they stay within the permitted development (PD) rules for your type of house," says Robert Wood, Director of Simply Loft.


Since most dormer loft conversions are deemed permitted development, you will only need planning permissions if your project exceeds certain conditions and limits, such as:

  • You live in a conservation area or it is a listed building.

  • The height of the dormer conversion exceeds the height of the original roof.

  • The conversion affects neighbours through overshadowing or overlooking.

  • Bats reside in your loft. As a protected species, you need permission before disturbing their habitat.

Pro Tip: It is always best to consult an expert before initiating a project. You can chat with one of our chartered architects for expert advice and personalised guidance, and can even get their support with planning permissions.


What are the Best Dormer Conversion Ideas?


While what you do with your dormer conversion is fully up to your preferences and needs, we’ve compiled some practical ideas to spark inspiration for your upcoming project.


  • Create a home office - For people who need a well-designed workspace to promote productivity when working from home, a dormer loft conversion is an excellent opportunity to build a beautiful office.


Create a home office - For people who need a well-designed workspace to promote productivity when working from home, a dormer loft conversion is an excellent opportunity to build a beautiful office.

  • Convert it into a bedroom: Whether you need more space for guests or your kids, a dormer bedroom conversion could be the perfect solution.


Convert it into a bedroom: Whether you need more space for guests or your kids, a dormer bedroom conversion could be the perfect solution.

  • Add extra living space: A dormer loft conversion could serve as a lounge area where you can chill with family and friends.


Add extra living space: A dormer loft conversion could serve as a lounge area where you can chill with family and friends.

  • Include a kitchenette or bathroom: Depending on the space available, you can enhance your space with more functionality, for example, including a kitchenette with a living room, or a bathroom with a bedroom.


Include a kitchenette or bathroom: Depending on the space available, you can enhance your space with more functionality, for example, including a kitchenette with a living room, or a bathroom with a bedroom.

  • Use it as a meditation space: Being a well-lit room, a dormer loft conversion presents a great space to de-stress, relax, and enjoy peaceful meditation.


Use it as a meditation space: Being a well-lit room, a dormer loft conversion presents a great space to de-stress, relax, and enjoy peaceful meditation.

Conclusion


Although dormer loft conversions can be expensive, their innumerable benefits make them a potentially worthwhile renovation. If it's something you've been considering, list down what your family’s requirements are, analyse your budget, and use the above guide to start thinking about whether or not a dormer loft conversion is right for you.


Planning a dormer loft conversion? Book one of our Structural Engineering Gurus for a 30-minute video call. Transforming your home into a space you love shouldn't be a daunting task. With HiiGuru you can save time, avoid costly mistakes and bring your goals to life with experts by your side.

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