Mansard Loft Conversion

Mansard Loft Conversion

What is a Mansard Loft Conversion?

A Mansard Loft Conversion is normally built to the rear of your property, this alters your roof horizontally with an almost vertical 72 degree back wall. A Mansard Loft Conversion gives alot of habitable loft space to add a bedroom or a bathroom. The windows are usually placed within the box-shaped Dormer which projects a little, enhancing the internal space even further and allows natural light into your bedroom. This type of Loft Conversion is big enough to have two bedrooms and a bathroom. Mansard Loft Conversions are apt for most property types and can be completed in many ways to compliment your existing property.


How much does a Mansard Loft Conversion Cost?

The Mansard loft conversion is often regarded as the most expensive due to the skilled work and size. The average cost of a Mansard Loft Conversion in London and the home counties is between 50k to £60k but this should be taken as a guide price because the approximate cost will depend on many factors such as size, design, planning permission fees and any extra fixture and fittings. At Loft Conversions Company we believe the Mansard conversion gives the most habitable space and will increase the value of your property significantly too.

Which House is ideal for a Mansard Loft Conversion? 

Mansard Roofs are most commonly found in Central and Greater London. It provides London homeowners a great opportunity to make the most out of their property. Mansard is ideal for most types of properties from detached to semi-detached and even some terraced houses in Central London. Mansard is suited for Victorian and Edwardian houses

Do Mansard Loft Conversions in London require Planning Permission? 

 Yes, as the structure of your property is altered therefore Mansard Properties do require Planning Permission. We suggest checking with your local authority in London and the surrounding areas to find out the latest planning policy requirements as some boroughs are stricter than others. In addition to planning permission, your finished mansard loft conversion will require building regulations approval.

What are the Advantages of having a Mansard Loft Conversion? 

The prime benefit of having a Mansard Loft Conversion is the ample extra space it creates, quite simply adding another floor to your property. Mansard allows forming an open-plan design or several rooms such as a master bedroom, bathroom, home office, or a chill-out pad. A Mansard loft conversion will increase your property's value by up to 25% if finished to a high standard. The exterior of the Mansard loft conversion can be completed in a wide range of materials, from slate or brick cladding to render or timber, perfectly complimenting the existing aesthetic of your property.


Many consider a mansard loft conversion as a great way to add a new dimension to their homes, not only because of the massive space it will provide but also the aesthetic feature it will grant your property once construction is finished. As a mansard loft is not a limited choice for a loft conversion that you can only get when you live in a specific type of property, the construction involved for this type is still most suitable for terraced houses in highly populated areas. There are three main types of mansard roof extensions: flat-topped, double-pitched, and butterfly roofs.


A mansard loft is the most complicated type of loft conversion because of the dramatic adjustment it will create to your house. But it will still depend on the architectural design that needs to be accomplished and the size of the property. Additionally, the builders you will hire for the project will also play a factor in the construction timeline so it is best if you’ll work with a team that has enough experience in converting lofts.


It is important that the development of a mansard loft on your property complies with fire safety protocols. It’s also included as a factor in building regulations that’s why it’s necessary that the construction of the loft conversion includes fire safety. The building plan for the mansard loft must indicate that if not all, most of the doors that will lead to the fire exit must be replaced with fire-resisting ones. This is to ensure that you’ll have enough time to escape when a fire breaks out in your house. Additionally, the installation of smoke alarms and sprinkler systems must be featured in the plan as well so you’ll be able to reduce the risk of getting fire injuries or deaths.


Yes, it will. Checking the type of roof you have will help us determine the work we need to do just to accomplish a mansard loft on your property. A rafter roof that’s commonly found in traditional houses is a much more convenient option if you’ll go ahead with a loft conversion since the structural support it features is uncomplicated. With this kind of roof, a mansard loft conversion is still possible but the cost will be more expensive because construction will require additional supports. You must also know that every type of roof has different structural requirements so it’s better to acquire a professional inspection of your house before finally deciding with a loft conversion.

What can we do for your Property in ?

If you would like to discuss the ways in which a Loft Conversion could enhance your home, call us on 0208 1020 675 or email to ask us any questions. For a free site survey and design consultation please fill out the form on the right and our team will get back to you as quickly as possible.