London’s Leading Home Extension Specialist


Thinking of carrying out an extension project on your property? Here at Simply Extend we have completed hundreds of house extension projects, we have compiled some frequently asked questions taken from common questions we get asked.

Still can’t find what you are looking for? Our friendly advisors will be able to help you, simply give us a call on 0800 917 7571 and a member of the team will be able to assist you further.


How long does an average home / kitchen extension take to build?

On average, building extensions in London can take 10-12 weeks to complete but this depends on a number of factors, the main one being the size of the building as well as the specification of the project – sometimes a big build can take longer. If you take a look at some of our completed work in London including areas of North London such as Highbury and Holloway, the projects have been of a fair size, including kitchen, diners, ensuite bathrooms and even under floor heating. Whilst these projects only took a few short months to complete, it cannot be said exactly how long your extension will take. When you book your consultation with Simply Extend, 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. A project manager will oversee the build every step of the way so if any changes in deadline occur, you will be informed straight away.

How quickly can you start to build an extension on my property?

Our lead in times are currently 2 – 4 weeks assuming that you have plans, structural calculations and party wall notices in place (if required). Simply Extend are extension builders that operate all over London, so depending on whether you’re in North London, South London, Richmond, Wimbledon or any of the surrounding areas, we might be able to begin the build in as little as two weeks after your specification is submitted. 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.  Our excellent team can answer any questions you might have about the ‘before’ stage of your extension. Please contact us on 0800 917 7571 for a more accurate estimate of start dates.

If we decide to use the Simply Extend architectural service, how long does it take to get plans drawn up?

Our process of building extensions in London begins with a site survey where a Simply Extend advisor will visit your home, completely free of charge. Once the visit has taken place, you will be provided with a quote – this quote isn’t set in stone, Simply Extend can change the quote as many times as needed before you commit. Once the contract is signed (with the set time scale), the plans can begin to be drawn up. With all of the above taken into consideration, it takes us, on average, between 4 – 5 weeks from signing the contract to get our client to agree on a set of plans, but of course we have had faster approvals if a client is in a particular hurry. Simply Extend aims to cater to every client’s individual needs and we pride ourselves on being the best extension builder in London.

I’ve had a site survey, how long will it take to receive my quotation?

Once a Simply Extend surveyor has visited your property and carried out a site survey it will take no longer than 1 week for you to receive a comprehensive quotation. If you have not received your quotation in this time, then please visit your junk email folder (as sometimes our quotations can end up there by accident!) or give our team a call on 0800 917 7571. Remember that Simply Extend values your thoughts and opinions and so if you wish to discuss the quotation or add extra things onto your design, then you can do so by speaking to one of our friendly advisers. Whether you’re in Islington, Highgate, Isleworth or Notting Hill and wish to have a kitchen extension in London, one of our side return extensions or any other home extension, Simply Extend will aim to cater to your needs.  Our prices are very competitive, don’t forget that we also offer a price match comparison service, so if you find a like for like extension quotation that is cheaper from a comparable firm then speak to our sales team to see if we are able to price match.

How long are your quotations valid for?

Our prices are reviewed from time to time to cover things like the increasing prices of materials and are therefore valid for a maximum of six months. During this time your quotation can be altered to further suit your needs if necessary. Simply Extend appreciate that home extensions in London are subject to change and as a home owner you might need to alter your original design. This is possible with Simply Extend.



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

You might be surprised to know that not all extensions require planning permission – see our question and answers section on permitted development, but for those that do, it can often take 8 weeks for plans to be approved through planning permission. In the meantime, you can check out our previous builds for interior inspiration for your own London extension.  From rear kitchen extensions to bathroom refurbishments and everything in between, by taking a look at the Simply Extend gallery, you are bound to find some great inspiration for your own place.

What is permitted development and can I build my extension under this process?

If your property is not in a conservation area you may have permitted development rights (PD). This means you can build your extension without having to go through the planning permission process. For more details on the requirements and criteria for this, please visit the UK planning portal by clicking here. If you are still not sure, just give Simply Extend a call and they will be happy to look into the issue for you. It is important to be sure that planning permission is not needed, before you go ahead with your extension.

What is the difference between permitted development rights and planning permission for extensions?

With planning permission, you are asking the council if your proposed extension is acceptable. It is open to rejection by them and/or your neighbours and will have to follow the local development plan. With permitted development you are asking the council to simply confirm that your plan fits within the permitted development criteria. The council will issue you a Lawful Development Letter if they agree. Technically you are not required to have the Lawful Development letter in place before the work starts and in fact there is no law stating you have to have it. This allows clients who request it, to start the work without waiting for the Lawful Development Letter, thus saving time.

What is a party wall agreement and do I need one for my extension?

A party wall agreement is required if your home has a wall that is connected to another property on either side. Each neighbour will have to be informed of the proposed works using a party wall notice form 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 issues that might arise due to work done on the party wall. It draws up an agreement between you and your neighbour on what needs to happen if there is a problem. By law your neighbour can insist you have one before the work starts. This process is handled by clients directly, however if required Simply Extend can advise you on this process and put you in touch with one of our certified party wall surveyors.


Types of Extensions

What different types of extensions can I build on my property?

There are many different types of extensions that can be added to your property such as rear kitchen extensions, side return extensions and even double storey extensions. Extensions in London are a great way to expand and totally transform your home space. Simply have built extensions all over London and with no job too big or small, you can guarantee that we will do a professional job. Want that ensuite bathroom you’ve been dreaming of? Want more kitchen space to entertain guests or dine as a family? Click here for ideas and inspiration as well as further information about the types of extensions that Simply Extend provide and the types of houses they have worked on. This should hopefully all help you decide on the type of extension you would like to ask Simply to build onto your property.

How much disruption should I expect throughout the build phase of an extension?

There is no doubt that building work can at times be disruptive and slightly stressful, after all we are completely altering your home! However, there are certain tips and measures that can be taken to ease this process. If budget allows, you may decide the best way to avoid the disruption is to move out throughout the construction phase. However, we know at times this can be realistic. Other steps are to build temporary kitchens to enable you to still cook and clean, or to build stud partitions to block out the dust from the rest of your home. Always remember to pack away any valuables or anything that could potentially be damaged as materials and equipment will be making their way through your home. It’s important to remember all the disruption will be worthwhile when you have your brand new, expertly built extension.

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

When you apply for a house extension, it doesn’t only create more space to live in, it also gives you the opportunity to transform the look and feel of your home and so you might also be considering refurbishment in other rooms if you feel your décor is a little out of date for the current London trends. Quite often, Simply Extend will carry out refurbishment work on bedrooms, living rooms, bathrooms and downstairs toilets and utility rooms. Please enquire for additional prices on your site survey.

How much does a home extension cost?

The price of a London home extension varies massively depending on what your specification is and what exactly you want doing with your extension. Some people require a small bedroom and ensuite, other households need a brand-new kitchen or living space and some even require double storey extensions. The style of your extension will also affect the cost, depending on the type of windows and doors you would like fitted. Having fitted many extensions in all the different areas of London, Simply Extend has created a cost page which will hopefully give you an idea of how much you can expect to pay or budget for. To visit the cost page, click here.

Do you build loft conversions?

Yes. We have a specialist loft conversion arm to our business called Simply Loft, who have converted hundreds of lofts all over London . We have many clients that use us to carry out a loft conversion and an extension at the same time, thus saving hassle and cost by avoiding having two separate contractors. Like Simply Extend, Simply Loft are the experts in their field and will guarantee a professional finish with their work so are worth considering if you would also like to utilise your loft space.

Do you build basement conversions?

Yes, our sister company Simply Basement is able to carry out basement conversions to properties.  Please visit our website for further information or book in with one of our specialist basement surveyors for a quotation.


Why Choose Simply Extend

Why should we choose Simply Extend for our extension?

When it comes to building extensions in London, whether that’s in the Kingston and Hampton areas of South West London, the North London town of Harringey or a busy part of central London, Simply Extend always execute their work to the highest level of professionalism using their network of skilled tradesmen. Not only this, but by choosing Simply Extend, you will have professional advice on hand to answer any questions you might have about before, during and even after the building process. We will begin by taking your initial ideas from design through to construction and when completed; backed by our ten-year warranty.  We have converted and expanded hundreds of homes all over London, so you can be assured your project is in safe hands.  Feel free to call us for your free no obligation site survey or to see a completed project near your home.

What insurances and guarantees do you have?

We have public liability, employee’s liability and the most important, contract all risk insurance. Documentation can be provided on request.

Am I able to visit some extension projects you have completed in my area?

Simply Extend have executed extensions in South London, kitchen extensions in North London, plus all the surrounding London areas and so if you are living in London and require an extension it is likely that there will be some of Simply Extend’s work in the vicinity and we are more than happy to share references with you. As well as this, you can visit the Simply Extend case study pages where you can see images and details of our previous work.

What areas of London do you cover?

We cover South London, North London, West London, Central London and everything in between so if you would like  a home extension in North London then please be sure to get in touch or visit our case study section to find out what work we have completed in your area.  Or call our friendly team on 0800 917 7571 and they will be able to advise whether we cover your postcode.

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