Dormer loft conversions everything you need to know

Dormer loft conversions and everything there is to know about dormer loft conversions. 

Dormer loft conversions are the most popular type of lofts and you will probably have noticed them in every neighborhood. This is mainly because they are versatile and can be installed on most types of properties from detached houses to top floor maisonettes (subject to planning approval). In terms of the process a dormer loft conversion is when a rectangular box shaped structure is built up in place of the pitched roof.


Dormer loft conversions cost from £38,000.00

Dormer loft conversions everything you need to know

What is a dormer loft conversion?


Dormer loft conversion has a new structure on your roof, flat roof and walls are added at a 90 degree angle to the floor. This gives much more usable space in the loft and a comfortable ceiling height. Typically dormers are located at the rear of the property. Generally the new structure must fit in line with the current height of the ridge although permission can be sought from the local planning department where the ridge is too low to achieve adequate head height. 

What are the different types of dormer loft conversions?


As there is quiet few dormer loft conversions here are the most popular ones, this is also dependent on type of house you have:

  • Flat roof dormer - these type of dormer loft conversions would be built at the rear of your terraced house, meaning the gable wall or boundary walls are already built originally, these type of dormers do increase your loft space rapidly and are very popular option.

  • Side dormers - the side of the sloped roof the dormer box is built 

  • Front pitched dormer - also known as gable dormer is a small dormer topped with small mini gable roof. 

  • L shaped dormer - one of the bigger options typically built on properties that have outriggers, these dormers have two parts that form L shape and add huge amount of space.

Dormer loft conversion
Dormer loft company london

Will i need planning permission for my dormer loft conversion?


One of the great advantages of dormer loft conversions is that they are included in the homeowners permitted development rights. These rights allow homeowners to add liveable space and extend their homes without needing to go through the full planning application process as long as specific criteria are met and guidelines are followed, some examples include: 


Your current home:

  • Is not a building containing one or more flats.

  • Has not already had additional storeys added to it under permitted development rights

  • Was not changed from non-residential to be used as a house under permitted development rights.

  • Was not built under permitted development rights.

  • Is not in a conservation area. 



Limitations on the proposed development:

  • Materials must be similar in appearance to the existing house

  • Volume of enlargement must not exceed the original roof space by more than:

    • 40 cubic metres for terraced houses; or

    • 50 cubic metres otherwise

  • Must not exceed the height of the existing roof.

  • The front roof must not exceed the existing roof slope. 

  • Must not include: verandas, balconies* or raised platforms (Juliette balconies are permitted). 

  • Side-facing windows must be obscure-glazed. 

Further details can be found here:

Dormer loft conversion

Is my home suitable for dormer loft conversion?


Technically any house that has pitched roof and enough head height would be able to have dormer loft conversion. Typical houses that have dormer loft conversions would be London terraced houses, end of terrace houses, semi detached house or detached houses. 

But also Edwardian, Victorian 1920s and 1930s, new builds and bungalows have widely benefited from the dormer loft conversions and those in conservation areas or flats and maisonettes.  

What are the benefits of the dormer loft conversion?


One of the main benefits of dormer loft conversions is to increase the value of the property by adding an extra bedroom and en-suite, however not all properties would be able to achieve this and it is dependent on location, circumstances or existing property condition. Unlike velux loft conversion the dormer loft conversion will allow vertical walls and normal stairs with skylights allowing light onto first floor dark areas, you would also benefit from additional storage and en-suite, most dormer loft conversion will add a good size bedroom space with a lot of options that can be added from Juliet balconies to flat roof skylights and built in wardrobes. Dormer loft conversions are cheaper then the other loft conversions in general. 

How much does dormer loft conversion cost in London and Hertfordshire areas?


The simple answer to question how much does dormer loft conversion cost in London and Hertfordshire areas is between £38,000.00 to £55,000.00 on average. 

Dormer loft conversion cost depend on many factors such as the existing condition of your existing roof, size of the roof, location of the existing staircase, are there any repairs to the existing home to be done, are chimneys in the way or they need removal or alterations, level of finishing, materials and labour needed and much more. 

Dormer loft conversion cost

How will you be sure the loft conversion does not require planning permission?


If you are not sure or want to have assurances then the best thing to do is to submit a Lawful Development Certificate application to your local council to confirm if your loft conversion meets the permitted development requirements and will determinate whether the proposed loft conversion is lawful. 

What type of spaces would dormer loft conversion allow me to have?


It is hugely dependent of the size of the loft, dormer loft conversions on terraced property will add up to 40 cubic meters and on semi detached or detached properties up to 50 cubic meters of space. 

  1. Dormer loft with en-suite - this is one of the most popular options and are absolutely fantastic, one of the biggest factors is that it will have a bathroom and will add another bedroom to the house. 

  2. Dormer loft multi-room with en-suite - it is possible to have two bedrooms and en-suite but it is all dependent on the size of the dormer loft conversion.

  3. Dormer loft game room or office - if you need extra room for work or gaming or play areas for children dormer loft conversion may be the answer, the dormer loft conversions offer great addition to the house and give lots extra space.

Dormer loft conversion ensuite

In name you can TRUST 

Over 16 years of Architecture and Construction experience

At Nuhous we are loft conversion experts a specialist loft company. We are also house extension builders a specialist in the field. With our in-house architectural design and construction team we deliver high quality loft conversions and house extensions across London and Hertfordshire areas. you can be rest assured we will start from design and planning stages to construction and finishing stages.

Free no obligation quote

We will provide you with the free quote for your loft conversion or house extension project, we also have have a price match, if you have found a cheaper quote come back to us and we will match it! Terms and conditions apply. 

Professional and Expert advice

10 year guarantee

Highly recommended

Inhouse architecture and construction

London based

Expert loft conversion company

Explore further

From this point you can get a free quote from us, get free advice about your loft conversion, home extension, new build, give us a follow on social media just search "nuhous" to stay up to date with our news

Free consultation

You can speak to us about your loft conversion or house extension project over the phone. Book your free 30 minute consultation.

Get a free quote

Get a free quote for your project, design and build loft conversions or house extensions. Fully detailed quotes available.

Knowledge Hub

Knowledge Hub

Find out about planning permission, building regulations or our blog and news about home style and living.



Looking to spread your cost with monthly payments? Our partners might be able to help with finance options.

call us