FAQ

The most commonly asked Questions on basement conversions, basement construction and extensions.

How much will it cost for a basement conversion?
Do I need Planning Permission?
I have a Cellar and want a basement conversion. Head height is limited. What do I need to consider so I can get the ball rolling?
I'll probably sell my house at some point in the future. What documents do I need to demonstrate that the basement is built to the correct standards?
How long do conversions take to complete?
What is BS8102?
What's the benefit of a cellar and basement conversion?
Do you guarantee your work?
Can I live in the property whilst the basement construction is in progress?
Must there be an existing cellar?
There are lots of basement companies, why should I choose Surrey & London Basement Company Ltd?
My ground floor seems to be solid concrete can I still have a basement conversion?
How much head height can you make for us? What is normal?
Do I need to let my neighbors know I am planning a basement construction?
Am I restricted to only having the basement under the foot print of my home?

Q. How much will it cost for a basement conversion?

A. Our aim is to provide extremely good value for money. However, it is difficult to generalise on costs because each of our projects varies in size and application. If you have some idea of budget, we can survey the possibilities within that price.

We have converted cellars for as little as £10,000 for simple waterproofing and finishing, but, on a much grander scale, have excavated to two storeys where there was no existing basement, with full finishing, at a cost in excess of £800,000.

An approximate guide for basement creation would be to budget £800-£1100 per cubic meter. This is affected by such variables as the amount of structural work you require, access, ground conditions, local authority charges and the list goes on.

For finishing off the created space or basement conversion of existing cellars you should allow £600-£1200 per square meter depending on finishes, level of specification, number of windows and final proposed use.

It really is a very complex question to answer and we regret we cannot be more specific. For a more accurate quote, with no obligation survey, please contact us to arrange a visit with one of our friendly surveyors.  We are interested in your ideas, there is no pressure and it may help you to talk it through informally with someone who has in-depth knowledge.

Whatever your budget and whatever your requirement, we really enjoy making it happen.

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Q. Do I need Planning Permission?

A. Many projects for basement construction don't need planning as a basement conversion will not change the external appearance of the building. This varies depending upon your local authority. In conservation areas, negotiation may have to take place with your conservation officer to ensure the proposed work is within current guidelines.  However, if you are planning to create a self contained dwelling, you will need permission. It's also likely that permission will be needed if additional visible windows and doors are to be added. We are happy to advise on planning implications at the quoting stage of your project and we can draw upon our wealth of knowledge and that of our associate engineers, architects, building control experts and planning consultants. But, if you prefer, we can handle all of this for you.

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Q. I have a Cellar and want a basement conversion. Head height is limited. What do I need to consider so I can get the ball rolling?

A. What type of property - detached, semi, terraced, apartment, freehold, leasehold...?

  • What is the approximate size of the existing basement?
  • What do you want to use the space for and what is it used for at present?
  • What construction are the walls, floors and ceilings (brick/stone/concrete)?
  • What are the existing and proposed plumbing and electrical services?
  • What is the current floor to ceiling height?  What do you want it to be?
  • What access routes are available in and out of the property?
  • What is the history of the space in respect of any water penetration; is it damp/wet or not?

Having answered these questions you will be well prepared for your free survey and quote and we will be able to accurately estimate a budget for your works. Please contact us using our contact form or call on 0844 257 3535.

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Q. I'll probably sell my house at some point in the future. What documents do I need to demonstrate that the basement is built to the correct standards?

A. A surveyor acting on behalf of a potential buyer will look closely at the cellar conversion to ensure that it complies with BS8102 (Protection of structures against water from the ground). They will be seeking to ensure that the cellar is not likely to fail and is of sound construction. You should be able to provide a specification for the works carried out, a guarantee from your chosen contractor and a Building Regulations Completion Certificate which demonstrates that an appointed building Inspector has visited the site during construction and is satisfied it is built correctly in accordance with the current building regulations. A specialist contractor will handle all of this to ensure you gain value to your home with the additions they have created.

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Q. How long do conversions take to complete?

A. This really depends on the size and complexity of your project. Our quotation includes an estimate of the construction time and we undertake to work continuously on your job wherever possible to reduce our onsite time. A small conversion, from start to finish can take as little as four weeks.

Dependant upon the size of the area and the extent of the works, approx. 12 – 24 weeks for a standard basement conversion, below the footprint, subject to size.

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Q. What is BS8102?

A. British Standard 8102:2009 is the 'Code of practice for protection of below ground structures against water from the ground'. In essence it is the primary design guide for structural waterproofing in the UK, with the recent update being released November 2009. If you are producing a waterproofing design, or advisors are designing on your behalf, this should take account of the considerations listed within this document. If you have further questions in respect of BS8102, please feel free to contact us.

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Q. What's the benefit of a cellar and basement conversion?

A. Instead of using valuable land and garden space from around your property, a basement conversion will add the benefit of a complete new floor level enabling the use of one or multiple rooms for a multitude of uses: home office, gymnasium, cinema, bedroom, sauna, nanny suite etc. One of the main reasons for choosing a basement conversion is the lack of suitable living space in many London properties.  When you balance this against the cost of moving, with stamp duty, removals, the increase in price of the new property, you can in most cases carry out a basement construction project for less money and increase the value of your home in excess to cover it. It really is a great way to gain the extra space.

You may have dreamed of the extra living or leisure space for years and this really is an opportunity to put your stamp on the property you love, so you can enjoy many more years in this space.

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Q. Do you guarantee your work?

A. Yes, all our work is covered by our 10-year warranty and 30 year manufacturer’s membrane guarantee. We carry product guarantee insurance in terms of the product we provide to you which is independent. We are PCA members and as such can offer insurance backed guarantees on the work we carry out. Our level of cover for your peace of mind and ours is substantial; it is complex work and we are specialists in our field. All details are available upon request.

Pump and control system servicing is required biannually. This gives us an opportunity to visit you again to check the system. As we take exceptional care at the work stage, apart from any circumstances beyond our control, there should be no problems throughout the life of the conversion.

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Q. Can I live in the property whilst the basement construction is in progress?

A. The majority of our clients remain in their homes during their basement conversion, which is a major advantage. We excavate in the front garden (when appropriate), where in most cases the window and light well will be. We then construct a secure covered hoarding around the area and this opening is used as our point of access throughout the works. This is not to say you shouldn't move out during the works. This type of work can be noisy and messy and, although we take great pains to keep disruption to a minimum, you may feel more comfortable, especially if you are normally at home during the day, to relocate during the excavation stages. Our teams are polite and courteous and realise you have to live there long after we have finished, so do their best to help with your neighbours and anyone this work may affect.

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Q. Must there be an existing cellar?

A. In basement construction there is no need for there to be any existing basement; it can help, but we can excavate down straight through the ground floor.  Another possibility is to utilise a small space at the front of the property to dig straight down, then cut through the foundation, mining out the footprint and structurally underpinning the walls above as we go.

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Q. There are lots of basement companies, why should I choose Surrey & London Basement Company Ltd?

A. We know your home is your most valuable asset. Over the years, we have built up a skilled workforce and grown in size considerably. Within this growth we have never lost sight of the values we embodied when we set the company up. We offer good value for money, a close personal and professional service, simple explanations, expertise and a fresh small company approach. We have an in-house team of experts, including surveying, planning & design, engineering and project management, enabling us to offer a full design and build service. It should be a turnkey solution with us and our previous projects and customer referrals mean the world to us.

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Q. My ground floor seems to be solid concrete can I still have a basement conversion?

A. Surrey & London Basement Company Ltd can draw upon a wealth of engineering experience to overcome problems such as these and it can be solved in many ways. The floor can be supported from underneath as we excavate so it is not disturbed. This causes the minimum amount of disruption. Another option is to remove it completely and replace after construction.  Each project is different, so please contact us and we will be happy to chat through your ideas.

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Q. How much head height can you make for us? What is normal?

A. In most cases we produce a finished head height of 2.4 meters (8ft). This is comfortable and feels airy and open.  You can have less and you can have very high ceilings, but this will affect the building costs.

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Q. Do I need to let my neighbors know I am planning a basement construction?

A. Yes, at the very least you should discuss this with them and consult with a party wall surveyor to agree the best course of action.  If you prefer, we can arrange for one to act on your behalf who will be able make party wall awards as required.

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Q. Am I restricted to only having the basement under the foot print of my home?

A. No the basement construction can be under the garden, driveway and any paths, depending upon ground conditions and from the ground level you would never even know it was there.

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If you have a question which has not been answered here, please contact us using the contact form to the right or call us on 0844 257 35 35.