Mansard Loft Conversion

Mansard loft conversions are generally considered to be the most complex style of loft conversion and allow for a truly unique design to transform the look and value of your property. Named after Francois Mansart, a renowned 17th Century French architect, Mansards are also renowned as the ultimate type of loft conversion available.

Mansard loft conversions run across the entire length of the building and are usually constructed at the rear of the property, with the roof extended outwards and a new wall created to meet the new loft floor at an inward slanting angle of at least 72°. Mansard loft conversions do require comprehensive planning and design thought but can be beautifully constructed with the right team of architectural designers and builders.

Mansard-roof loft conversions which can be installed for terraced, semi-detached and detached properties, can be great for a new guest room, study or additional storage space. There are different types of Mansard conversions to choose from such as single mansard loft conversions, L-shape mansard loft conversions and double mansard loft conversions.  There is no need to be put off by the complexity of Mansard loft conversions as London Builder London know the structural nuances and best practice to construct them specifically around your requirements. You can view the different types of Mansard Loft Conversion with the image slider below.

  • Although they complement different properties, mansard extensions are particularly well-suited to terraced houses because the creation of additional space is more significant to the often limited area. This makes them extremely popular in the suburban areas of London.
  • In most cases, Mansard conversions require planning permission due to the extensive structural changes and rear side pitch alteration to the roof. No need to worry though, Local Builder London have a great planning application success rate
  • Costs usually range from £1,500-£2,500 per m² for an excellent quality mansard loft conversion – Local Builder London will find the best price for you


  • Building dimensions and plans to ensure Permitted Development (PD)
  • What is the structural design of your roof?
  • A total ceiling height of 7ft 6in (2.3m) minimum at its highest point is required

Our Service Level Guarantee

    • Accurate Build-Cost Projections
    • Expert Project Management
    • Technical Specification Scope
    • Building Control
    • Fully Adhere to Permitted Development Rights

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