House Extensions London

North London House Extension Builders

Adding a luxury extension to your house in London or Hertfordshire does not need to be a hassle with the right team of architects, building specialists, interior designers and decorators who will turn your dream into reality. Whether you plan to build an open-plan area with sliding glass doors on the ground floor or add an extra bedroom on the first floor, our design and build team will prepare the plans, construct the extension and design and decorate the interiors. If you already have an architect or a designer, our team of builders in north London will work closely alongside them and extend your home following their drawings and specifications.

Once the construction of the extension is complete, you will get a building completion certificate. Our home extension services come with a ten-year structural warranty. Being one of the best building contractors in North London, Marriott Construction has built multiple single storey, double storey, wrap around, rear and side return house projects around north London and Hertfordshire. The exquisite craftsmanship of our projects shows the expert services we provide to our clients. Book a free no-obligation consultation today. A member of our professional extension services team will discuss your project with you and provide you with an estimated cost. Your vision and our experience will enable us to find the best solutions to the space problems in your North London property. 

Extensions completed by our Design and Build Team in North London

Rear house extension in London

Rear house extensions

Our client wanted to add an extra room to bring some light into his house and express his personality. Our extension builders achieved the objective by adding a rear house extension to this property in North London. The brick walls helped the expansion fit with the surroundings.

Kitchen extension in North London

Single storey extension

Our clients wanted to build a larger kitchen that would help bring more light into their North London home. Using the best materials, our extension experts added this kitchen extension to the house's back. The Velux roof windows helped brighten the house interiors.

Two storey extension in North West London

Double storey extension

Our client decided to build a two-storey extension. As this property in north London sits on a slope, the project architect designed a home extension with a half basement and sliding glass doors. Our builders, who have years of experience in this field, completed the building process following the plans.

Design of the Different Types of Home Extensions

When it comes to designing the best house extension for your house, start by considering whether you want to build a single or a double-storey extension with a flat or a pitched roof. To get an idea if your extension plans are likely to be accepted, take a look around your area to see what types of extensions other people have built. Your house extension design might qualify under the Permitted Development, in which case you will not need to apply for Planning Permission. A good architect or London design and build contractors should be able to offer free advice regarding planning and building permissions. 

Building a home or a kitchen extension in London is cost-effective, so without having to move or buy a new house, you can opt for this kind of renovation and get a new room or the kitchen you like. With our versatile service extension in north London, our experienced team of architects, building experts and interior design specialists work with you, taking into account your style preferences to add the perfect kitchen or living space to your property.

Single storey wrap around extension in London

Single Storey House and Kitchen Extensions

A single-storey extension is a popular type of home improvement project, as it connects the house with the garden. There are three kinds of one storey extensions: rear, side return and wrap-around. (pictured).

While most single storey rear and side return house extensions qualify under the Permitted Development, a wrap around extension requires Planning Permission. Our North London house extension builders could help you add space to create a large open-plan kitchen while making a connection with your back garden, a bright lounge area with a fireplace, or a gym. 

Double storey house extension in Hertfordshire

Double Storey House Extensions

A double-storey house extension might be cost-effective than a single storey, as the roof and the foundations tend to be the expensive parts of the build overall. 

Our north London builders, who have years of experience, could add a two storey extension to the back or the side of your property. In order to comply with regulations, two-storey side extensions need to have a pitched roof similar in design to the existing one. You could go for a kitchen extension, and add an extra bedroom, a playroom, or an office.

Extending a House FAQs

If you have any questions regarding our London home extension services or would like to request a free consultation with our expert extension builders, contact us today!

Our client's satisfaction is our number one priority. We have teamed up with several architects and interior designers including award-winning Alan Cox Associates, to offer a 3D visualisation of your London extension plans, as well as interior design services if required. 

A house extension cost will depend on the quality of the finish and the materials used. While basic extensions in London can be as cheap as £2000 per square metre, if you want to build a top quality high end extension, the cost can go up to £5000 per sq. m.

High-quality home extensions can increase the value of your North London or Hertfordshire property by up to 25 per cent, which exceeds the expense.

A small one storey rear or side extension can be completed within three or four months. Wrap-around extensions and larger rear and side return extensions will take longer to build. A double-storey extension might take up to nine months to complete.

House extensions are growing in popularity as house renovation projects due to the high demand for larger homes. It is an innovative and affordable construction method for specialist builders and the homeowners who decide to add extra space to their property. The different types of house extensions can get you many benefits. As well as the obvious advantages for you and your family of an extension, such as extra space to co-habit in, it can also add light to your London home, making it look brighter and welcoming. 

The most common and popular uses for house extensions in London are:

  • Extending the back of the property into an open plan kitchen and dining area while utilising garden space by bringing the outdoors in.
  • Creating an additional bedroom, games room, playroom, home office or gym.
Building a house extension in London FAQs


Rear House Extension

Great project management delivered on time and on budget. Imaginative solutions in problem solving. Very high standard of finish. Very tidy site throughout the build. Prepared to go the extra mile.


Enquire now
  • 183 Edgware Road
  • London
  • NW9 6LP
  • 2 Athenaeum Road
  • Whetstone
  • N20 9AE

Book a site visit - 0748 529 8186
Other enquiries - 0208 205 8173
Hours: Mon to Fri 09:00 - 17:00

We operate across North London, North West London and Hertfordshire. Including BarnetBushey, Camden, Edgware, Finchley, Hampstead, Hendon, IslingtonMill Hill, Potters BarStoke Newington and Watford