Loft Conversions London – Loft Types


Hip to Gable

Hip to gable loft conversions aim to increase the relatively small existing space of properties with hipped roofs. The sloping, or ‘hipped’ side of a roof is changed to a flat gable end.

  • Planning permission may be needed
  • Extra space can be used for a variety of purposes, including offices or extra living space
  • Suitable for detached, semi-detached, chalet and bungalow properties

To find out more about hip to gable loft conversions, including their suitability for different types of property and planning permission considerations, click here


L-shaped dormer explained

Converting your loft can be good value for money when improving your home and increasing your living space. An L-shaped dormer loft conversion can be a good option for creating more room at the top of your home. Popular on period, terraced properties, this type of loft conversion creates a lot of space, usually adding at least a couple of rooms to your property. In this post, we give you a bit more information about what is involved in this type of conversion.



This type of loft conversion involves constructing a vertical wall from the bottom of the sloping roof. A flat roof is then built to meet the vertical wall, in order to give maximum headroom in the loft extension.

  • Most common type of loft conversion
  • Can also be gable fronted or hipped roofed
  • Planning permission often not needed

To find out more about dormer loft conversions, including pros, cons, a volume calculator and planning permission requirements, click here


This type of loft conversion is typically constructed at the rear of your property, has a flat roof and a back wall that slopes inwards at 72 degrees. As mansard loft conversions involve a significant change to a property’s structure, they can be more expensive than other conversions, and involve more construction work.

  • Particularly common in urban areas and terraced housing
  • Windows typically housed in dormers
  • Often require planning permission

To find out more about mansard loft conversions, including cost considerations and conversion ideas, click here.

If you’d like to talk to us about your loft conversion or get a free quote, feel free to get in touch with us today using our online contact form or calling us on:


What does ‘dormer’ mean?

A ‘dormer’ loft conversion is a structural extension that projects vertically from the plane of a sloping roof. An L-shaped dormer typically involves constructing two dormers – one sits on the main body of the house and the other then extends out over the rear addition of the property. The dormers meet to create the ‘L’ shape. This type of conversion is most suited to Victorian and Edwardian properties that tend to have the kitchen and bathroom at the rear. An advantage of the L-shaped conversion is that you are able to replicate your first floor in terms of space and design.


Under Permitted Development Rights (introduced in 2008 by the Department of Communities and Local Government), you typically do not need to have planning permission to build a loft extension on a house if the extension is adding less than 50 cubic metres of new space to the property (and less than 40 cubic metres if the house is a terrace). However, there are some cases when you will need planning permission and it is wise to double check the requirements with your local authority before starting your project. For example, you will need planning permission if the side of your house with the conversion faces the road or if your house is in a designated area (e.g. conservation area, Area of Outstanding Natural Beauty, etc.). The conversion will still need Building Regulations approval and it is worth having an approved design before you start work.

Design and construction

On first glance, L-shaped dormers appear to have a flat roof. Instead, they tend to be built with a 1:50 fall to the side to ensure that water does not pool on the roof of the loft. To make the extension look less ‘top-heavy’, it is common to step the sides of the dormer slightly and create a small border around the edge of the structure, blending in with the existing slope of the roof. There are several other technical considerations to take into account during design and construction. For example, you will need to consider fire precautions and escape windows, ventilation measures (especially if the extension includes a bathroom or shower room), thermal and sound insulation of the new structure, and how you are going to supply electrics and heat to the new space. Investing in a good design will ensure that your extension adds to the ‘look and feel’ of the original property, rather than detracting from it.