Mansard roof extensions

London architect guide

Inspiration and ideas

Mansard roof extensions are the most cost effective way to maximise the floor area of your house or flat when compared to adding the same floor area with a rear or side extension.  Mansard roofs are a widespread and traditional method of adding an extra storey to the top of a Georgian, Victorian or Edwardian building.

Named after a French architect, Francois Mansart, the mansard roof comprises a sloping roof clad in slate or tiles, set back behind a parapet, with dormer or attic windows, which either project from or are recessed into the slope. It emerged in the eighteenth century in Britain, when it was also referred to as a kirb roof. It allows extra accommodation at roof level, partially hidden behind a parapet wall, without having a great impact on the appearance of the façade below. 

As part of this mansard roof extensions London architect guide we have selected some projects to lend architectural inspiration and design ideas for your Mansard roof extension.

You can read here our latest Loft conversion cost planning permission architect guide for everything you need to know about your loft conversion project.

How much value does a .loft conversion add? Please read our advice to Samm Webb as published for Homebuilding & Renovating on March 2023, and click below to read our full advice and guide to homeowners as prepared by George for the purposes of this article: Architect guide – How much value does a loft conversion add.

Architect designed mansard roof house extension Angel Islington N1 Bathroom design Mansard roof extensions London | Home design
Architect designed mansard roof extension Finsbury Park Islington N7 Kitchen e1582379059483 Mansard roof extensions London | Home design
1216 Fulham Broadway H Fulham SW6 7UH Flat alterations to a mansard roof Front elevation 200x200 Mansard roof extensions London | Home design

Mansard roof extensions London architect guide – Design aspirations and key considerations

Designing the staircase is the single most important thing we will need to consider for any type of roof extension or loft conversion. There are building regulation restrictions in regards to the risers, goings, and head heights in regards to the staircase. There are fire regulations to consider, and plumbing/drainage issues when an en-suite is to be created. The design challenge is about how to exercise intelligent spatial planning around all the relevant restrictions so that both the new loft layout, and the layout of the floor below do not get compromised when the staircase is added to the existing floor plan.

Start considering how you would like to use your new space, and how it will interact with the rest of your home. It’s important that the new extension blends with the rest of the building and is easily accessible, so when considering the staircase think about its long-term use as much as its style.

During the design development stage we will get to explore lots of ideas but you can start the process now by considering answers to questions as such:

  • “How can we best use this new room? Will it be our new master-bedroom, a study space, a nanny’s room? What other bedrooms are available in the house, and what would work best for our changing needs and family?”
  • “Space permitting, how about adding an en-suite, a walk-in wardrobe, or even a coffee area in front of a Juliet balcony?”
  • “What do we think about rooflights in the bedroom? They bring more light into the room but how about the rain ticking on the glass; is it charming or just plain annoying?”
  • “Planning permitting, how about we sacrifice some of the internal floor area to create a small balcony with doors opening up to it directly from our new (master-) bedroom?”

Mansard roof extensions London architect guide – Types and options for your home project

 Mansard roof extensions London | Home design

Angel Islington N1 Mansard roof extension by GOAStudio London residential architecture

This type of roof extension is appropriate for properties with what is commonly known as “butterfly” or “V” roofs. Such roof extensions practically add a full new level to your property, and they can be the perfect solution to houses or flats in conservation areas. The planners will take a view on whether a mansard roof can be added and where. And here is the rule of thumb when it comes to planning: if the majority of the properties in your terrace have mansard roofs then it is likely the planners will approve an application for a mansard roof to your property.

There are two main types of mansard roofs:

Traditional | Traditionally most mansard roofs have two separate slopes or pitches, however they are more expensive to construct and less common these days.

Modern | Modern roof extensions often have a flat roof profile at the top, with a gentle slope to the rear.

There are several crucial elements to the correct appearance of a mansard roof, namely materials, slope of the roof, proportion of the dormer windows and extension of the party walls and chimneys. Such roof extensions always require planning permission from your local authority.

GOAStudio London residential architecture media opinion publications 2 Mansard roof extensions London | Home design

iBuild magazine – Impressive renovation case study – South Hampstead residential house extension – February 2024

"GOAStudio's renovation and extension project in South Hampstead stands as a testament to the delicate art of preserving history while embracing the demands of contemporary living." This month our South Hampstead residential house extension and refurbishment project...

The Telegraph | How to get a bigger home in an unforgiving market

"As the inflation rate has started to fall and mortgage rates have drifted down, George Omalianakis, of GOAStudio London architects, says the appetite for renovations has started to creep up. “Homeowners are deciding that the future looks a bit better now and it is...

Ideal Home | Kitchen extension cost – what to budget for a new and large room

You want to land on an extension size that is just large enough to meet your internal needs. Going beyond this would be a waste of money. 'You will discover the right size by playing around with a few plans and layouts to see how best you can organise the internal...

Country Living – 9no. kitchen flooring ideas for a refreshed look. Tips and ideas by George Omalianakis, GOAStudio

9 kitchen flooring ideas for a refreshed look - Plus advice on practical choices for busy spaces, upcycling your existing tiles and how to pick underfloor heating. Article by Jayne Dowle, Country Living "The biggest trend of all in kitchen flooring in 2023 will be...

Homebuilding & Renovating | How much value does a loft conversion add

How much value does a loft conversion add? "The typical value added can be around 10% to 20% if creating a new bedroom and ensuite with a loft conversion, explains architect George Omalianakis from GOAStudio architects. He adds that the value increase will depend on...

Build It magazine | Lighting for kitchen diner extensions

"In general, there are two main impressions you can create with natural light. The theatre stage effect plays with the contrast between the lighter and darker areas, meaning less is more when it comes to rooflights. By reducing the amount of overhead light coming in,...

Architectural plans

Architectural plans and professional guidance for your home project You will need to prepare architectural plans for your home project. They are often called “architect plans” however they do not need to be prepared by chartered architects (ARB / RIBA) as such. While...

Terraced house extension plans

Terraced house extension plans and professional guidance for your home project   Do you own a Georgian, Edwardian or Victorian house? Is it terraced, semi-detached or detached? And would you like to add a single or double storey extension? In all these cases you...

Architects London – GOAStudio London residential architecture

Architects London GOAStudio London residential architecture We are London architects with a very specific focus, skillset and expertise and we work on residential projects across London. George Omalianakis is an expert London architect for residential extensions and...

Loft conversion cost planning permission architect guide

LOFT CONVERSION COST, ADDED VALUE, AND PLANNING PERMISSIONS By GOAStudio London residential architecture What loft conversion rooms add value?How much does a loft conversion cost?Do loft conversions add value? What is a hip-to-gable loft conversion?What is a mansard...

Rear house extension ideas photo gallery

REAR HOUSE EXTENSION IDEAS PHOTO GALLERYBy GOAStudio London residential architecture Clad in brick or clad in timber.Fully glazed or half glazed. Timber frames or steel frames. Round skylights or walk-on skylights. Regular roofs or irregular roofs.Choose a shape, any...

Find interior residential RIBA architects for extensions near me

A HOW-TO GUIDE SEARCHING ARCHITECTS ONLINE FOR YOUR HOME PROJECT "find architects near me" "find an RIBA architect near me" "architect firms near me" "residential architects near me" "architects for extensions near me" "interior architects near me" We are often asked...

Householder planning permission. Haringey Noel Park Conservation Area.

Addition of a single storey rear extension and internal alterations to a single family dwelling in N22, Haringey.Area and context The site is a two-storey terrace dwellinghouse on the south side of Maurice Avenue. The property is located within the Noel Park...

Bromley BR3 house extension planning approval

Single storey rear extension and alterations to a house at Bromley BR3 - Approval by GOAStudio London residential architecture We have just obtained a planning approval for one of our current projects in Bromley BR3. For our latest Bromley BR3 house extension planning...

New planning approval Rear garden flat extension Westminster NW6

Planning approval for the addition of a single storey rear extension to a garden flat in Westminster, NW6. To include the replacement of windows to the front elevation. The new planning approval for a rear garden flat extension Westminster NW6 was issued by the...

New planning approval Conservation Area Waltham Forest E17

Planning approval Conservation Area Waltham Forest E17. To include the replacement of three timber windows to front and one timber window to rear with heritage uPVC double glazed windows - Orford Road Conservation Area, Waltham Forest in September 2022. The new...

New planning approval Rear house extension Enfield N21

Rear house extension Enfield N21 - We were appointed to design the renovations and extensions for a single family dwelling in a conservation area at Enfield N21. We have just obtained planning approval for a single storey rear ground floor extension to create a...

New planning approval rear house extension Barnet EN4

Rear house extension Barnet EN4 - We were appointed to design the renovations and the addition of a rear extension for a single family dwelling at Barnet EN4. We have just obtained planning approval for a single storey rear ground floor extension to create a combined...

New planning approval | House extensions Ealing W3

House extensions Ealing W3 - We were appointed to design the renovations and extensions for a single family dwelling at Ealing W3. We have just obtained planning approval for a single storey rear ground floor extension to create a combined kitchen, dining and living...

New planning approval | Double rear extension Tower Hamlets E1

Double rear extension Tower Hamlets E1 - We proposed and obtained approval for the addition of a double storey rear extension to a ground floor maisonette flat; the planning approval included the creation of an external terraced area and associated internal and...

New planning approval | Rear house extension Enfield EN2

Rear house extension Enfield EN2 - We proposed the addition of a 4m. deep rear extension to create an enlarged kitchen and dining area that opens up to the rear garden. We made sure that the proposal could be considered as Permitted Development and we applied to...

New planning approval | Single storey front side house extension Barnet N2

New planning approval | Single storey front side house extension Barnet N2; to include internal alterations to create a new bedroom.

Let's chat

If you need expert advice from an RIBA Chartered Architect please email us at george@goastudio.co.uk with the following:

  • the full address of your property,
  • a couple of photographs showing the areas you would like to extend and renovate,
  • a brief description of the changes you would like to carry out to your home, and
  • any estate agent or similar plans you might have available.

We will

  • assess the information and get back to you with initial advice about what might be feasible,
  • search the public planning records of your local authority to find similar planning approvals nearby,
  • prepare a free consultation to include information on design ideas, architectural fee estimates, project stages and requirements, and
  • afterwards we will prepare a detailed fixed fee proposal to cover the architectural services you will need for your project.

We are here to assist with your project.

Introducing GOAStudio London residential architecture limited

“George Omalianakis Architecture Studio – GOAStudio London residential architecture” was set up in 2009 to provide architectural services and assist home owners with their residential projects across London.

George Omalianakis is a multi-award winning chartered architect with the Royal Institute of British Architects (RIBA), registered with the  Architects Registration Board (ARB), and has extensive experience in working on a variety of residential, commercial and educational sectors.

Which? magazine residential expert and contributor. Ideal Home magazine residential expert and contributor. Member of the Green Register of Construction professionals.

We provide architectural services in the following London Boroughs:

Read our design, planning, and architectural guides above if you seek advice for your project.

We can help you with these home extensions and renovations:

See our guides above for ideas, inspiration and architectural advice for your home project.

GOAStudio London residential architecture limited 2024 300x300 Mansard roof extensions London | Home design

We specialise in

  • Greener homes
  • Retrofit and energy efficiency for older and traditional buildings
  • Conservation areas
  • Listed Buildings
  • Homeowner architectural services
  • Developer architectural services

RIBA Chartered architect services

CONTACT US

GOAStudio London residential architecture limited, 86-90 Paul Street, EC2A 4NE, Hackney

GOAStudio London residential architecture limited, Chestnut Avenue South, E17 9EJ, Waltham Forest

t: 0203 984 3005
e: george@goastudio.co.uk
e: media@goastudio.co.uk

 

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