Mansard Loft Conversion

A Simple Guide to Mansard Loft Conversion

Compared to other types, Mansard Loft Conversion requires more construction work. However, it provides a great deal of extra living space in your house. It does not matter which type of home you have; it is suitable for all kinds of properties.

What is A Mansard Loft Conversion?

This type of conversion is named after a French architect, Francois Mansart. You can say that it is an extension that covers the entire roof of the property. Typically, this conversion can be found at the rear side of the house, which requires changes to the sloping side of the roof. The roof of the flat is flat, and windows fitted in small dormers.

Planning Permission for Mansard Loft Conversion

Unlike other types of conversion, this specific type requires planning permission. The reason is that it creates maximum living space in the home. It adds an entirely new storey to your property. That is why; it requires changes in the shape and structure of the roof and hence needed planning permission from the local authority.

How Much Does It Cost?

A mansard loft conversion costs more than other types such as hip-to-gable or dormer loft conversion. The main reason is that it provides a great deal of space by significantly changing the structure of the roof. Hence, it requires more work to be done to convert the loft. You can say that it provides more space compared to other types and therefore more expensive. After you get what you pay for, to get a more specific estimate, you can visit the cost of loft conversion.

Is a Mansard Loft Conversion Suitable for Your Property?

Well, the mansard roofs are very common in urban areas and London. You can even notice a house with mansard roof across whole rows of terraced properties. On the other hand, dormer flat roof extensions are more common in suburban areas. The reason is that they are cheaper and easy to build.

In short, a mansard loft conversion is suitable for any type of property including terraced, detached, semi-detached houses as well as bungalow, and chalets. If we talk about the aesthetics, mansard walls have brickwork, clad or rendered whichever best suits you.


  • A mansard conversion provides more living space compared to other options
  • Suitable for almost any type of property
  • The finishes can be done in different ways to match the style of the existing building


  • A mansard loft conversion does require planning permission
  • It requires changes in the structure of the roof and hence more expensive
  • More construction work is required for this conversion

Can Your Home Handle the Weight of a Loft Conversion?

It is obvious that a loft conversion puts more weight to your house and hence requires some work on the structure of the property. To make sure, you need to examine the foundation of the property. A building control officer also needs to consider these elements by digging a hole to expose the foundation. If your house required changes in the foundation, then the cost will increase.

Enough Head Height for The Conversion

You need to ask the architectural services provider about the headroom you will have after the conversion. Typically, it ends up in less headroom which is a disappointment for the homeowners. Furthermore, you need to keep in mind that you need a loft conversion staircase. It is essential that the staircase rise above the old one. It should not rise above in a bedroom. Otherwise, you will end up losing an entire room.

If you are going to convert the entire space, then you need to move the water and heating system elsewhere. You need to consider such things before planning a mansard loft conversion.

Loft Fire Safety

Fire safety of the home has little effect on bungalows. You need to make sure that windows in the loft are large enough to escape out of. A new floor requires 30 minutes of fire protection, and a fire door should separate the attic. For this, you can use skylight windows which are made explicitly with this in mind.

Loft Conversion Insulation

You also need to consider the energy efficiency standards. Installing insulation in the loft is complicated, but you can do this while replacing the tiles at the same time, which can achieve good airtightness. If you are not replacing the roofs, then you can install insulation cut between the rafters. We will recommend you to use high-quality insulation to meet high energy efficiency standards.

Storage Space

Converting your loft means, you are going to lose some storage space in the house. You need to deal with this problem by using the eaves behind the ashlaring. Furthermore, you can make the storage space warm by insulating the rafter line. You can also use built-in wardrobes in the bedrooms to store your valuable belongings.