Mansard Loft Conversion: 17 Designs for Added Living Space

A mansard loft conversion provides a smart solution for adding living space to your home. There are several options available in terms of how an attic extension is achieved structurally, including dormer windows, hip-to-gable additions and mansard extensions. 

The loft conversion route you choose will depend largely on the features of your existing house and planning guidelines in the local area.

Here we showcase 17 excellent examples of how a mansard loft conversion can lend extra living space to your home.

1. Transform Your Terrace With a Mansard Loft Conversion

Amos Goldreich Architecture is behind the transformation of this Victorian terraced property in North London. The project encompassed a side extension, plus the addition of a mansard loft conversion. From a planning perspective, a mansard extension was the sensible route forward, as other houses nearby had already carried out similar schemes for their loft conversion ideas. 

For the family living in the house, adding as much square footage as possible was the top priority, and a mansard offered better use internally than a dormer extension. 

The entirety of the original roof structure had to be replaced with a new steel structure to accommodate the new addition on the top floor. Zinc cladding was used for the exterior. This material has also been used to the clad the ground floor extension, creating a cohesive look. 

2. Freshen Up Any Existing Features

Often, this type of loft conversion can change the overall look of a home and so provides an opportunity to give other elements of the exterior a makeover.

As part of the mansard loft conversion and full refurbishment, all windows in this house – including the large window in the mansard extension – were replaced with double glazed, timber units. Matching windows provide a cohesive look.

Oak flooring has been laid throughout the house, infusing character and warmth. The selection of material finishes used throughout the property was kept to a minimum, so the house retains a streamlined, unfussy feel. 

The wall behind the bed offers inset shelves, maximising space in the loft bedroom, while keeping the space as neat and clutter-free as possible.

3. Utilise a Mansard Roof on Both Elevations to Add Space

Mansard roofs don't simply need to be used on one elevation. This front and rear mansard loft conversion was designed and built by Simply Loft to incorporate a living area, inset office space and sunny roof terrace. 

On the right-hand side of the outdoor terrace, two full length windows drench the office area in sunshine. The roof terrace serves as an outdoor relaxation and entertaining area with far-reaching views across London. 

4. Allow Time to Remove and Rebuild Features

Darren Oldfield Architects masterminded the design for this mansard loft conversion in the London Borough of Lambeth. From a planning perspective, tight guidelines around London butterfly roofs (where there’s a valley running from front to back between the two slopes of the roof) meant that a mansard loft conversion was the only option when it came to extending upwards. 

The existing roof slopes were removed completely so the new structural floor could be put in. From there, the two sections of sloping roof were rebuilt on top of that, as well as raising the side walls and the chimneys. 

As the project also encompassed a ground floor rear extension idea, work on site took between seven and eight months. However, if you were only tackling the loft conversion, architect Darren Oldfield estimates that the project would take around three and a half months. 

5. Choose the Right Cladding Materials for a Mansard Loft Conversion

There are numerous exterior finishing options for your mansard loft conversion. For example, tiles, metal, brick or render can be used to complement the existing walls and roof of the house. 

Slate tiles are a popular choice and are often seen on period properties, lending slate roofs a classic feel that keeps homes looking fresh. 

This refurbishment and extension of a Victorian House in Hackney features a zinc exterior to establish a sleek, contemporary aesthetic. While the shade of the zinc mirrors the roof coverings on houses nearby, the smooth metal finish provides a modern take on the original roofing material. Zinc is also corrosion resistant, low maintenance and recyclable. 

The design for this project was masterminded by Archmongers. 

6. Introduce High-Level Glazing for Added Light

Sunshine floods into the space from all directions, thanks to clerestory windows (high-level glazing) on either side of the extension and a large casement window at the end. A strip of glazing has also been installed overhead, drenching the loft with natural light and opening up views of the sky. 

The shape and scale of this mansard loft conversion evokes the feel of a canal barge. Bespoke birch plywood joinery, clad in linoleum, has been incorporated to maximise every nook and cranny of this light-filled office in the attic. 

7. Ask Yourself What Will Add Value

This rear mansard roof extension in South London added a new bedroom, bathroom and dressing room to a mid-terrace first-floor flat. The crowning jewel of this extension is an L-shaped outdoor terrace, which provides the occupants with a sun-soaked outdoor space to enjoy. 

The addition of the roof terrace required planning permission from the local council. Outdoor features like this are particularly popular in urban areas, where garden space is at a premium, so are often a smart choice for adding value to your property. 

8. Maximise Space with Built-in Storage

This example of rear mansard bedroom loft conversion ideas has added a generous amount of space and height. The light-filled top floor has been designed to serve multiple purposes — a sofa provides a haven for relaxation away from the rest of the house, while a large desk in the corner provides a quiet spot for working from home. With a loft conversion bathroom, it can also serve as a master bedroom.

Bespoke built-in joinery also provides plenty of storage, maximising every square inch of space against the sloping walls of the mansard. 

9. Devise a Strong Design Strategy

This project, by Paul Archer Design, has revolutionised a Victorian terraced house in East London. As well as adding a ground floor rear extension, a loft extension was a key part of the design strategy for adding more space to the property. 

Local planners were keen on the idea of a mansard roof that would fit in with other houses in the area; a dormer window was not permitted. The new mansard loft conversion over the rear window of the house provides additional bedrooms and bathrooms, plus space for a small home office design.

10. Take Advantage of the Extra Head Room

One of the key bonuses of a mansard loft conversion is the extra head room they provide on the top floor, as this scheme demonstrates. 

Here, a traditional, large sash window has been incorporated within a dormer structure in the bathroom, which projects outwards from the sloping plane of the mansard’s walls. This helps increase both light and space, two key components of any practical en suite.

11. Consider the Structure of Your Home

This Victorian house in South London has been transformed via a mansard loft conversion. Previously, the attic had been cramped and unusable, so a mansard was the best option in terms of adding additional square footage.

This route was also viewed favourably by local planners, as mansards are often regarded as the most aesthetically pleasing type of loft extension. This is because the sloping walls give them a softer appearance than a dormer structure that’s built vertically from the rear plane of the roof.

12. Ensure Your Mansard Loft Conversion Has Practical Benefits

The new bedroom and bathroom in this mansard loft conversion were fitted out with practicality in mind. 

Dormer windows have been incorporated to make sure the space is filled with natural light. Additional storage was also incorporated by installing built-in under eaves cupboards, plus a fitted closet. 

Having a mansard extension rather than a dormer means the bedroom benefits from plenty of head room across the whole zone.

13. Enhance Your En Suite Experience

Incorporating a dormer window above the bath and shower area ensures this ensuite has the advantage of plenty of space. 

In most loft conversions, figuring out how to fit a shower (in terms of head room) can be one of the biggest challenges — a common solution is to place the shower where the ridge height is highest, and then place the WC in the eaves where less headroom is required. 

However, by going down the mansard route, the owners of this house had more leeway when it came to laying out the sanitaryware.

14. Liven Up Your Home's Layout

Before Pinchin Architects stepped in, this terraced house in East London suffered from a tight floorplan, with a poor sense of connection between each of the rooms. 

The brief was to re-jig the layout and extend upwards via a mansard extension, turning the two-bedroom property into a three-bed home. 

London stock bricks were used to build up the parapet walls of the mansard addition, which has been clad in Welsh slate roof tiles for both durability and stylistic consistency, similar to other properties in the area.

15. Alter the Floorplan Where Necessary

This mansard loft conversion project has provided a new master bedroom and en suite on the top floor of the house. 

In order to link the first floor to the new second floor above, several changes to the floorplan were required, including a new bathroom and an alteration to the hallway position. 

Bespoke built-in joinery has been crafted for the master bed in order to maximise every inch of available space, right up to ceiling height. 

16. Improve the Functionality of Your Living Space

This mansard loft conversion was designed with the idea of work-life balance in mind. It has allowed plenty of space for a new living area on the top floor of this mid-terrace home in South London. 

The living area has been designed as a multi-functional zone that provides a meditation room, artist’s studio and reading room. The room benefits from dual aspect views, thanks to the bifold doors that lead out to the roof terrace, plus the two smaller dormer windows that look out onto the road at the front of the property.

17. Embrace Fresh Design Opportunities

This project afforded some interesting design opportunities when it came to creating the mansard loft conversion. 

By inserting the steelwork in certain locations, a large open volume was created.  The roof slope leading down towards the bathroom door is comprised of a fake slope, with a tiny loft space behind it (for storage). This has established a symmetrical ridge line above the bed, creating plenty of height, space and drama that would not have been possible with a flat roof dormer. 

The same pitched effect has been recreated, to a smaller scale, in the bathroom. If the owners of the house had wanted an open-plan layout, rather than incorporating the en suite, it would even have been possible to vault the structure all the way up to the ridge line to infuse the top floor with extra wow-factor.

What Is a Mansard Loft Conversion?

Named after French architect Francois Mansard, a typical mansard loft conversion can span the entire width of the roof, so it has the potential to add plenty of space to your home. 

It is typically built outwards from the rear of the roof at an angle of around 72° to establish a structure with sloping walls and a flat roof. Windows are often fitted within small dormers. 

Mansard extensions do tend to be one of the most involved type of loft conversion in terms of the work that’s required, so as a minimum, expect to budget £50,000 for your scheme. 

Plus, mansards will alter the aesthetic of your roof significantly, so will usually require planning permission (unlike dormers, which can often be achieved under Permitted Development).