Do not move - extend!
If it feels like your house is getting smaller, and you need more space - extend it with us! Now it is easier than ever before to design and build a chic kitchen extension, home gym or open-plan living space for family feasts and parties with friends. Couple this with a refurbishment of the rest of your property, and you end up with something that feels new and modern without having to move.

House extensions London

There are only two necessary ingredients for a beautiful extension – You, with a vision for a luxury space and Us, the builders and interior designers, to make that vision of contemporary or classical interior a reality. So, why wait? Contact us today!

We specialise in all types of bespoke home extensions designed to increase your space and bring new life into your home. Our extensions are built with your needs in mind, and our experienced builders can complete your dream extension in a very short time.

We are dedicated to producing the highest levels of workmanship and service to you, always welcoming new ideas and methods of construction.

Why Choose Us?

We price match

Got a lower price? Tell us, and we will match it


Up to 10 years of structural work warranty

Stress-Free project

A dedicated project manager will manage your build work daily

Specialist fixtures and fittings

Bespoke skylights, continuous floors and bi-folding doors

Fixed prices and deadlines in the contract

A quick planning time; design and construction work with no hidden surprises

Combined 100 years of experience

Customers have faith in our knowledge, expertise

No subcontractors

We keep all our work in-house

Our on-site evaluation is a careful review of your home extension goals, the structural aspects of your home and the feasibility of your plans

Not many properties need planning permission, but you need to be aware of the probability of local authority approval being required.

Step by step

If your extension is to be built close to your neighbour's boundary, it may well be worth investigating whether you would need a party wall agreement or not. If you do, we have specialists who can help you through this process.

One of our project managers will be designated to you as your dedicated project manager, your point of communication throughout the build and the person responsible for coordinating all aspects of your project.

Different types

of house extensions


Porches are typically small extensions to the front of a house, although they can be much more extensive and can be built to the side or back. Common examples include simple structures of only brick walls, columns, windows or doors. Due to size, most porches do not need planning permission, and as long as the porch is isolated from the house by an internal door and not heated, they will not require much paperwork.


Relatively simple structures that are typically made of uPVC, timber or aluminium. Some conservatories need planning permission, and some do not.


A sunroom is a conservatory with regular roof extension types and walls, including lots of glazing. They are durable and warm while also bringing in a lot of light. Due to the costs involved and the fact that they are more complex to build than a wrap-around conservatory, it is desirable to employ both an architectural company and an experienced builder. Planning permission rules for sunrooms are very similar to those for conservatories. However, building control approval will surely be required.

Single storey side and rear house extension

Single storey house extensions are constructed against a part of the house so that one or more sides of the extension are connected to the home, and there is only the ground floor and any basement built to it. Single storey extensions require building control approval, but they may not need planning permission.

Single Storey Extension can add notable value to your home, and you can turn your home extension into a:

Dining Room
Open-plan Living Room
Home office

Two storey or multi-storey extension

A multi-storey extension can be constructed to most elevations of an existing building.

A double-storey extension can be used to add a bedroom or bathroom upstairs or even create an open plan living-dining room with dramatic ceiling height. The impact on neighbours can be much more significant; this can only be built onto detached or semi-detached houses with a suitably sized side plot or garden.

Wrap around house extension

Wrap-around extensions are built by joining a side extension and a rear extension together, forming an L shaped wrap around an existing house. You should choose to have an open plan wrap around extension to build a beautifully spacious and illuminated area.

An over-structure extension

An over-structure extension is an extension atop an existing structure such as a garage, a living/dining room or kitchen. A lot of detached and semi-detached houses usually have a single storey side garage. This garage creates a chance for an additional extension on top of it.

The cost of house extension

Side return house extensions are less expensive than single-storey rear extensions.

Single storey rear extensions are cheaper than a wrap-around or double-storey extension. Your taste and requirements will directly affect the total cost of the extension.

The minimum cost is £1,500 per square meter. However, it can go up to £6,000 if you like beautiful things. In some extensions, the glazing cost alone was more than £30,000.

Get in touch with us, and we will answer promptly and can even visit the property the same day in an emergency.

Why choose us?

  • Professional Quotations
  • Up to 5 years Work Warranty
  • Own Designers
  • Specialists in High End and difficult projects
  • Member of Federation of Master Builders
  • Trustmark Member
  • Health & Safety compliant
  • We have decades of Experience
  • Friendly, reliable and clean Builders
  • We cover London and a 50 miles radius
  • Residential and Commercial Services
contact us

feedback from our customers

We might want to express gratitude toward Red Builders for the Refurbishment they finished for us and the work done. We were intrigued by the professional approach of the entire staff, we have got endless commendations from all who see and use it. The team was obliging and set aside a significant effort to clarify all the information required from the design drawings, the advancement of the work to the completed venture. A point by point receipt was given for all the work and materials with no hidden cost. Words can't describe how cheerful we are with our new home. If we describe Red Builders, they are perfectionist professionals who caused us to feel secure, realizing the completed project would be accurate and neat, and it was. We have prescribed Red Builders to everybody searching for building work.

Leonn Berry

We are completely pleased with the change in our cellar, and we can't thank you enough for all your difficult work and your endeavors. We especially valued the counsel on a few changes Red Builders proposed which prompted considerably more productive utilization of room. We are very happy with your assistance, and we trust we get the chance to cooperate once more. The project manager and his group kept to the contract just as spending plan and consistently refreshed us on the turn of events and choices that we expected to make. The builders were respectful toour home, keeping the noise to the possible minimum, additionally keeping the spot perfect and clean. It was a wonderful experience, and we are very much satisfied. With the team's understanding and skills, everything was on schedule, they conveyed a phenomenal completion. We would recommend Red Builders to every one of our relatives and every house owner.

Claire Keating

Red Builders was to make some significant alterations and a loft extension to our home. We requested some critical changes during development, and the project manager was happy to give professional recommendations on every issue. From the underlying idea on to its fulfilment, we were surprised by their attention to detail approach and the priceless guidance he gave all through. The project manager arranged the breakdown of cost precisely, with straightforwardness, and trustworthiness. His group of builders were first-rate and did their best. I was so astonished by the work they accomplished every day to the point that the work was finished before the cutoff times. We are certain to recommend Red Builders Building Company to every single customer.

Joe Whaley

We applied to different companies for quotes and got what we viewed as a reasonable and realistic quote for a genuinely extensive renovation of our home from Red Builders. The project manager and his group worked admirably and exceeded our desires. They included us in the selection process for the property, way to deal with the work and specifications. They were truly flexible and effectively obliged our decisions for additional work. The work has been done to the most professional level in a friendly, considerate and ideal style. Red Builders entire staff was gathered outside of our home ten minutes before the start time. The things that surprised us more than anything was the way that the project manager recollects everything about the details and takes individual liability for ensuring that you, the customer, are totally happy with the work that you need to be done. I have worked with different building organizations on various under takings throughout the long term. Red Builders are most likely the best that I have worked with, and I have no hesitation in suggesting him. Catch him in case you can!

Bridget Snooks

I am writing to thank you for your expertise, knowledge, reliable attitude showed by yourself and Red Builders team to the fruitful outcome of this project. We asked Red Builders to redesign a little flat and, despite the fact that the flat is small, it was significantly difficult to renovate it as it required a detailed renovation. Red Builders performed brilliantly. The Red Builders staff we were in touch with were amazingly capable and pleasant. As in most of such cases with are design, little issues emerged during the remaking period. Red Builders had the option to manage these issues in the most effective and practical manner. The project came in on the financial plan and due to the schedule. They did a wonderful job, and we currently love our flat. When the activity was done, Red Builders kept on following up and disclose things to us about the flat and its equipment after we moved in. I would highly suggest Red Builders.

Kindly pass my gratitude to all engaged with this project.

Jonathan Gough

A little more than a year back, I planned my first renovation project. I had never done anything like this, and after the web research, I sourced 4-5 quotes. I chose to go for Red Builders since they were sensible and their quote was all around organized and detailed. The Job included a lower ground expansion and house redesign. I don't have anything but beneficial comments about capability. Their work was done to the highest level. Their tiling, carpentry and painting were remarkable, and the project was finished on schedule and due to the plan. They were negotiable about the inside plan changes and permitted me to be engaged with the cycle even to the point of helping me source-specific installations I needed for the house, keeping in topic with the style we had gone for. They gave me useful recommendations on specific components I had disregarded, for example, up-cycling the current wood planks, extra water siphons required and incorporating the outer bi-folds to make the augmentation even from the outside instead of inside. On-demand Red Builders made cabinetry around our chimney to match our new kitchen and truly, the craftsmanship and detailing makes them appear identical. When the undertaking was done, it was hard to accept that it was the same house.

George Elliot

When embarking on discovering an organization to plan and build our office, I had clear models at the top of the priority list. The organization must be lively, clever, solid, overflowing with thoughts and value for money. Red Builders beat the competition by a reasonable mile. Indeed, even before winning the project, the attention they paid to us was unmatched. When we began, the norms didn't drop. They committed an over the top measure of time to my venture and went far above what was required even to where it was evident it wasn't to their greatest advantage to do so. They were very supportive all through the process, continually delivering on our details and deadlines and totally adaptable toour tasteful changing preferences. They're similar to an extended family on building site. Without any doubt, the best I've worked with.

Ryan Woodcock

I have been suggested Red Builders through a friend of mine who had their kitchen wonderfully extended so we chose to reach them about a potential loft conversion and we couldn't be more grateful. The plans were delivered very fast, precisely, and I truly felt they accepted our interests and thoughts, parts that were not achievable were given different other options, and they truly set us straight during this process. We are happy with the outcomes from the start to the end. Strongly recommended. It was a pleasurable experience, and I wouldn't hesitate to use again.

David Walker

We are living abroad, and after a tenant had harmed our terraced house, we found that we need to set out on a top to toe restoration of our property. We got various quotes, and the Red Builders reaction was the most careful and thorough. Red Builders were incredibly useful in working through the selection and reacting quickly to each of our inquiries and concerns. Red Builders might not have been the cheapest reply we got, however, there was absolute clarity on what we were paying for and the nature of work we were getting. The project manager and his group at that point dealt with the venture, especially professionally - with regular and definite email and photograph refreshes, they exceeded all expectations in conveying a remarkable outcome for us. Our home presently looks spectacular - and each renting office that has seen it has remarked on the exceptionally high caliber of the work. In case we needed to do this once more, we wouldn't spare a moment to call Red Builders, and are very glad to prescribe them to anybody searching for top quality, productive, friendly or more all very professional and experienced building company.

Jennifer Smith

Red Builders changed over a mid-Victorian patio loft. It was done due to the deadlines confirmed at the beginning and the budget approved, with a magnificent quality completion. The group of manufacturers, builders, electricians and plumbers set up by Red Builders were unpretentious and extremely enterprising. When there were inquiries en route, they were replied, and the Red Builders group were consistently accessible on the mobile if necessary. Red Builders were flexible and responsive. I was not anticipating works in the house, but once they were in progress, I was incredibly satisfied with how they went. I would suggest Red Builders without a second thought and would use them again for a similar activity without hesitation.

Amelia Morrison