Getting an extension, requires a financial investment from you. We want to ensure we answer any questions you may have.

Architechs Drawings
Project Management
Extension build
Kitchen Extension
interior design

Can my home be extended?

The majority of UK properties can be extended, this depends on a variety of different factors like: The size of your garden or your side return, the location of the property, local council and environmental stipulations and guidance, the age of the property. One the most important factors is the space that you have outside, and the size and design of the extension you want. If you have not already got plans drawn-up, or planning permission in place, we can let you know at our initial visit if what you want to do is possible or not.


How long does a home / kitchen extension take to build?

On average, building extensions in London can take anywhere between 10-16 weeks to complete, but this depends on a number of actors, such as: the size of the building, technical or planning specifications related the build or to local area. When you book your initial consultation with us, we will be able to give you an estimated time based on the amount of work you would like us to carry out on your home, as well as the type of materials or finishing’s you want. Your project manager will oversee every step the build, so if any changes in deadline occur, the reason will be discussed with you straight away.

Does an extension add value to my property?

An extension designed and built by Darwin Home Improvements could add between 20-25% to the value of your home, depending on the size and type of extension you chose as well as where your property is located.

How much does a home extension cost?

Unfortunately, there is no simple answer to this question. Every home extension differs enormously depending on what specification you want, what fixtures, fitting and features you want in your extension. Some customers require a downstairs toilet in the extension, some customers want a large open plan kitchen with all the mod-cons, whilst other just want to add more living space and some want a double storey extension. The style of your extension will also affect the cost, depending on the type of windows, roof and doors you would like fitted.

How quickly can you start to build my extension?

Our lead in times are currently 4– 6 weeks assuming that you already have design plans, structural calculations, planning application submitted and party wall notices in place (if required). At Darwin Home Improvements we have building projects across West London, so depending if a current extension project is near completion, we might be able to begin the build in as little as two weeks after terms and conditions and roles and responsibilities have been discussed and agreed. Of course, you will need to have received planning permission from all the relevant places and considered potential blockers such as party walls before any work can begin.  If you have any questions, we can answer any questions about the ‘before’ stage of your extension, we are always happy to answer any questions you may have.

Do I need an architect or a structural engineer?

The role of an architect is to design a project that turns a customer’s broad idea into a practical, safe and aesthetically pleasing reality that meets all planning and Building Regulation requirements.

A structural engineer’s job is to ensure the proposed structure is safe and supported correctly. The engineer will take into account all the materials to be used in the build, the location of the site, the weight of the build etc and then calculate exactly which supporting materials should be used.


You don't always need an architect or structural engineer, it depends on what you want and what type of extension you want. Darwin Home Improvements can advise you on whether you need an architect or structural engineer for the type of extension you want.

How long will it take to receive my estimate and job breakdown?

Once we have visited your property and carried out a site survey, you will receive your comprehensive job breakdown of the main components of the build, and cost estimate within 5 days. Once we have agreed to go ahead, we will then discuss all aspects of the build, to include: extension plans, kitchen design, fixtures and fittings. This way you get a more comprehensive job breakdown list, with a more accurate costing. At Darwin Home Improvements we value your thoughts and opinions and so if you wish to discuss the quotation or wish to add extra things onto your design, then you can do so at any stage of the process.

How long does it take for a set of plans to be approved for my extension?

Not all extensions require planning permission. If your extension does need planning permission, it can often take up to 8 weeks for planning application to be approved through planning permission. We can help you this process, this needs to be discussed at the start and  roles and responsibilities need to be set out in the terms and conditions of our contract.

Do I need a party wall agreement for my extension?

A party wall agreement is required if your home has a wall that is connected to another property on either side, such as neighbours. Depending if you have neighbours on both side, each neighbour will have to be informed of the proposed works using a party wall notice form, this must be given at least two calendar months before the intended start of the build. The party wall agreement is there to protect you and your neighbour from any potential issues that may arise due to work being done on the party wall. It is a legal agreement between you and your neighbour on what needs to happen if there is a problem. By law your neighbour can insist you have a party wall agreement in place before any work can start. This part of the process is normally done by you the customer, however if required Darwin Home Improvements can put you in touch with a certified party wall surveyor.

What kind of extension can I build on my property?

Because space is at a premium in London, adding an extension in a great way to expand and totally transform your home space. There many different types of house extensions options available. Each house extension is dependant to the type of property you have. At Darwin Home Improvements we will explain to you the different types of extension options that can be built on your home, we will also explain to you the pros and cons different extensions dependant on your wants and needs.


At Darwin Home Improvements we will discuss your requirements with you in detail, this will enable us to identify the best type of extension that would suit your needs as well as the type and location of your property and any restrictions. We will also discuss what the extension is being used for, the features and fitting you want.

How much disruption will I experience during the build of my extension?

There is no way of getting away from the fact, that building work can at times be disruptive regardless of the best planning and preparations completed before hand. There are certain options that can be taken to reduce the disruption and make it easier for you and your family. You may decide to avoid the disruption all together and move out during the build. If you are getting a new kitchen fitted as part of the build, you could continue to use the old kitchen until the knock trough phase of the build. When needed we will put in temporary stud partitions to block out the dust from the rest of your home.

Can I have other refurbishment work carried out to my home at the same time as my extension?

It makes sense to make the most of the disruption cause by the build, so if you are wondering about transforming the look and feel of other parts of your home it may be wise to do all the work in one go. We have carried out renovation and refurbishment on bedrooms, living rooms, bathrooms at the same time as doing extensions.

Why should we choose Darwin Home Improvements to build our extension?

At Darwin Home Improvements we always deliver the highest level of craftsmanship, professionalism and expertise to every job we do. We specialise in bringing innovation, style and functionality to life, turning our customers ideas and visions into reality. From day one you have a dedicated personal Project Manager who will be on hand to help and advise you through the entire build process, keeping you informed on the progress of your project with weekly updates of how you project is going, to keep your project on time and on budget. This has helped us to become one of West London’s leading building companies.

We provide all our customers with a detailed quote which includes a comprehensive job breakdown list, with a project planner with integrated timelines and expected completion date. Our team of skilled and qualified craftspeople work to continually exceed our customers’ expectations at all stages of the build. 


What is your payment structure?

Apart from your initial to confirm the job, all payments are staged over the course of the build.

See below:


Payment terms and conditions:

Initial payment to confirm job and book time into the diary. This comes off the overall cost of the quote.

Payment is 6 instalments and paid via bank transfer.

  • 1st  Payment of......transferred into bank 2 weeks (date to be agreed) prior to start of job 

  • 2nd Payment of.....  transferred into bank one quarter (date to be agreed)of the way through the build

  • 3rd Payment of ..... transferred into bank second third(date to be agreed) of the way through the build

  • 4th Payment of.....  transferred into bank one quarter (date to be agreed)of the way through the build

  • 5th Payment of ..... transferred into bank second third(date to be agreed) of the way through the build

  • 6th Payment of ..... transferred into bank 2 weeks after job is complete

All payments are acknowledged and confirm by company receipt as part of the terms of the contract


What guarantees, warranties, and certificates are given?

During the extension build, building inspectors will be visiting your home at various stages of the build to check the work. The building inspectors work for you and are there to make sure everything is within government rules and regulations. You should liaise with the building inspector and your builder to arrange these visits. Once the project is completed they will give you a completion certificate, as well as this you will be issued with a electrical certificate from a qualified electrician, and a Gas certificate if any work on been done by a qualified gas safe engineer on any gas appliances that have been worked on.

Do you do other building work?

Yes, at Darwin Home Improvements we carry out all kinds of building work, we especially known for carrying bespoke property transformations. This means we go into a property and strip it all out right back down the walls and floor joists, then the extension is converted, extension built and the entire property is redesigned and decorated to your specification. Everything will be build or renovate is done to your chosen style and specification.

Contact us today for a free quote

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