Basements
We’ve talked endlessly about London basement conversions… that’s only because we love converting basements, our customers value our experience and knowledge about basement building…and if we say so ourselves, we are very good at it. The basements we have built have ultimately put a smile on our customer’s faces; it’s that space they have envisioned that adds the ‘wow’ to their home, whether it’s a space of calm or a space to entertain. That doesn’t mean however, that the process of building these basements have been completely smooth-sailing. We have experienced several challenges in some of the conversions we’ve built. The key, of course, is to overcome these challenges by finding workable solutions.
If you are thinking about converting your basement, be aware of some of these potential roadblocks along the way, but do remember there is always a solution to every problem.
- Planning permission
Excavating a basement is a major structural undertaking and will require planning permission via your local council. Make sure you appoint an experienced architect who understands your local council’s requirements. Plans that are not detailed and do not abide by council regulations are likely to get rejected. If you are in a conservation area, you will need to take additional rules and conditions into considerations. In most councils, the consultation is 8 weeks from the time of submission of the plans. Any changes will cause the 8-week period to re-start. It’s important to get it right the first time.
Having said that, in Kensington and Chelsea there have been over 800 planning applications for basements submitted in the last 5 years. Only 10% are rejected and these are almost always resubmitted. So, the odds are in your favour.
- Love thy neighbour
You will probably have to enter into a party wall agreement with your neighbour. We suggest you involve your neighbour in your plans to get them on side before you put your planning application in. If they object after the plans are in, you might have to amend your plans and restart the 8-week consultation period, further delaying your project.
- Risk of groundwater
The impact of groundwater driven by both the general water table and often hidden underground streams can throw a spanner in your works. Encountering water adds to the complexity as excavating wet clay takes longer, can clog up conveyor belts and requires continuous pumping.
- Diggability
It’s also more difficult to install basements where there is a solid floor. There are some cases where it really is not feasible to fit a basement. In fact, many modern terraces and townhouses that are built on raft foundations can’t be underpinned, so can’t have basements. It’s also important to have good access for the excavation work: too close to a boundary or the road and it could be difficult for a JCB to get in.
- Waterproofing or tanking
We believe this is one of the most important aspects of basement building. Poor waterproofing techniques resulting in leaks and floods can destroy all the hard work in converting a basement into a beautiful living space. Problems associated with this are:
- Failure to properly seal service penetrations in basement walls.
- Poor backfilling which can lead to punctures in tanking.
One of the solutions to this problem is to install a cavity membrane system.
SDA Build London is proudly accredited by the UK’s leading waterproofing brand, Delta, with all our basement conversion projects installing their cutting-edge Delta Membrane Systems. This high-density polyethylene covering is applied to the walls, floors and ceilings of a basement dig out, where it blocks, controls and drains any potential ground water ingress from entering a property. It can be applied to new, existing and retrofit projects, and is flexible and durable so it can cope with movement or vibration in the home – important as this is often the cause of basement flooding! All our Delta Membrane installations come with a 30-year warranty that ensures your basement is protected.
If you are considering building a basement, give us a call. We’ll be happy to visit your property, discuss your ideas and share our thoughts on the feasibility of a basement on your property, any potential pitfalls and how we can overcome them.
Call us on 0208 191 7595, email us at enquiries@sdabuildlondon.co.uk or book a Free Refurbishment Consultation via our website. We’d love to hear from you.
Read MoreAsk not what you can do in your basement… Ask what your basement can do for you. Ever dreamed of that one extra space in your home that would ‘complete’ it? It’s that space that will add the wow factor to your home or the retreat that will transport you to a place of peace and quiet.
So, what can you do with your basement? The answer? Just about anything (within reason of course).
We have built several basements in homes across South West London with a variety of different uses, designs and styles. See our some of our Projects here.
A basement can be unapologetically large, spanning across the entire width and breadth of your ground floor. You are literally spoiled for choice in terms of what you might want to build in your basement.
We see the basement as being used in primarily two ways. Externally; where its use is for entertaining friends and family and internally where its use is for your family as a haven for precious family time with of course some overlap now and again.
If you are thinking about using it as a space for entertaining and guests, think about installing a fully equipped Games Room? One with a table tennis table, pool table, a small golf putting area? Add a bar to one and side and we imagine yours would be the ultimate party house.
We recently built a state-of-the-art cinema room at a home in Fulham. With Hollywood as the theme and a wine cellar boasting some of the finest wines in the world, this basement embodies, style, class and sophistication.
If, like one of our clients, you are a wine connoisseur, you can create a large temperature controlled wine cellar to house and protect your vintage wines and barrels.
Speaking of connoisseurs, one of our clients has converted their basement into an inspired art gallery to showcase his expensive and highly prized art collection.
If, on the other hand, you want a space that is focussed on yourself and your family, you could create a master bedroom with an en-suite, walk in wardrobe and dressing room that could be fit for the Queen. Or you could pack the kids off to their “underground’ playroom, giving them a space to unwind, have friends over and use as a den.
A home cinema with luxurious seating and surround sound systems would be the ideal setting for a Friday night in with the family; popcorn, candyfloss and perhaps The Sound of Music, James Bond or Mamma Mia, depending on your taste.
For those with slightly less dramatic tastes a family/TV room in the basement is exactly what’s needed to relax with in your dressing gown with a glass of wine and watch your favourite TV shows after a long day at work.
We recently built a stunning kitchen/diner in the basement at a home in Wandsworth. Not only was there no compromise on anything they wanted due the expanse of space, but it created a central point for the family to gather in the mornings and evenings away from distractions of homework and TV. This kitchen had two entrances; one from inside and one from outside, which led directly into their stunning garden. This gave this underground kitchen huge amounts of natural sunlight and a sense of space and air.
If you’ve always loved the smell of books and dreamed of living in the British Library, well, you can almost do that by creating a library in your basement. With comfortable seating, a movable ladder across your collections of precious books and maybe some soft music in the background, you could be living your dream.
Do you prefer to work from home and avoid a painful commute? Why not make the basement into your home office? If you have staff, you could create an entrance via your garden so they don’t have to go through the house. Or you could create consulting rooms if you are a medical professional like a physiotherapist or a psychiatrist. It would be easy enough to create cubicles for examinations and privacy.
If fitness is your thing, then how about a fully equipped gym in your basement? You’ll have absolutely no excuses to avoid working out. Weather, time, transport… all these excuses will be deemed null and void J. All you have to do is make sure you are ready to pump up your heart on the treadmill and tone those muscles with the weights.
And whilst you are in fitness mode, you could build a swimming pool in your basement. This is luxury at the highest level. Imagine the feeling of bliss when you enter the heated pool after a session at the gym or after a tiring day in the office.
As evident, the possibilities are endless. Your basement can serve whatever purpose you want it to.
As basement specialists, we know what is possible and not possible when building basements. Give us a call on 0208 191 7595 or email us at enquiries@sdabuildlondon.co.uk to discuss your ideas with us. Or why not book a FREE refurbishment consultation via our website. We’ll be happy to come around to your property, discuss your needs and ideas and share some of our recommendations.
Read MoreDo you have a growing family and need more space? Or just want a home that has the wow factor? Have you moved into a new home and are thinking about renovating to have your stamp on it? A garden basement may just be what you need. It’s unique and can be used for whatever you want; a playroom, a gym, a swimming pool, a kitchen-diner or a home office.
Not only will it add space to your existing home, but it has also proven to increase the value of property.
Here’ why should you build a basement under your garden & not under the existing structure.
A garden basement, allows for a brighter, lighter space as you can install roof lights, lightwells or terraces and flood the basement with natural light.
External openings directly into the garden allow for fresh air. Basements under the existing structure have limited scope for natural air and sunlight. Garden basements, on the other hand, by their very nature and position on your property are ideal to allow for fresh air and light.
A garden basement can be much bigger than a basement under your home if you have a large garden. There’s nothing to stop you (other than council approval) from creating a basement under your garden that spans across it.
Often, a garden basement is quicker to build than one that’s under the existing property simply from an ease of access perspective. Equipment for a basement conversion is large, heavy and cumbersome and much harder to manoeuvre inside a property than outside. Equipment like the conveyor belt and piling rig can easily be installed outdoors. Want to know how much your basement might cost? Find out here.
One of the most useful facts of a garden basement is its reduced impact to your and your neighbour’s properties from a structural perspective. And with no building added to the back of your house, it’s subtlety, protects your neighbour’s right to light.
We’ve probably got you excited about your garden basement now… is your head spinning with ideas and plans for that amazing space you are going to create? That’s wonderful and please do give us a call if you need someone to help you through it.
However, before you dive into the project, there are some elements you need to consider.
- Planning – Please speak to your local council to understand the basement planning policies in your borough. Different areas have different requirements and it’s important to be well-informed about what you can and cannot do. Find out more about basement building regulations.
- Is your property in a conservation area? If so, there are some very specific requirements that you need to adhere to.
- Trees- check if there are any Tree Protection Orders (TPO”s) on your property. You will also need to assess whether your basement will have an impact on the trees in both yours and your neighbour’s properties.
- Party Wall Awards –You will need a party wall award if your home is semi-detached or terraced as you will be digging close enough to your neighbour’s property. If you are in a detached home, other criteria come into play. Speak to a party wall specialist to assess whether you need an agreement.
- Hire a competent and experienced architect. Your architect is the single most important person when you are embarking on any extension or conversion project. Find out how you can find the right architect here.
- Of course, your building contractor is as important as your architect. Make sure you appoint a builder who is experienced with building basements. A builder who has never done a basement, may be perfectly capable of building an extension, but a basement has considerations that only an experienced basement builder will know.
At SDA Build London, we have worked on several homes across South West London and have built some stunning basements. Please do visit our Projects page to have a browse of the work we have completed.
If you are thinking about a garden basement or even a basement under your home, do give us a call on 0208 191 7595 or email us at enquiries@sdabuildlondon.co.uk or better still why not book a FREE consultation via our website. We’d be happy to visit your property, assess your needs and give you some recommendations and options. We look forward to hearing from you.
Read MoreBasement conversions are a popular way of increasing space and square footage and adding value to your home, especially where building up is not an option. We have built several basements in Central London, allowing families to expand their living area, avoid being uprooted and save the prohibitive costs of moving home. In fact, the value to cost ratio of building a basement is more favourable than many people expect.
We thought we’d share some of our insights on the factors that will affect the cost of converting a basement.
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Existing cellar
Do you already have an existing space in your basement that you want to convert into something habitable? If a space already exists, this is the best-case scenario of a basement conversion as the heavy-lifting has already been done. The cost of converting an existing cellar into something more usable would be approximately £2000 per m2, depending on the specs you choose. The costs will increase if you need to increase the head heights or lower the floor.
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Basement excavation
If you need to excavate a basement, naturally the costs will be higher simply because the amount of work required will be more. The specific areas that will need to be costed are:
- Removal of excess material under the home. You will need to factor in digging equipment, skips and additional labour.
- Tanking and waterproofing. This is the single most important aspect of a basement conversion. Find out why.
- Underpinning walls
- Rerouting drains
- Adapting to ground conditions which may only be revealed once your builder starts excavating
- Adapting to water table levels.
You should expect the cost of a new basement excavation to be approx. £3000-4500 per m2.
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Use of Basement
What will the room be used for? This is a vital factor in determining the cost. Basements are used for a variety of rooms including, gyms, cinema rooms, garden rooms, kitchens, playrooms, swimming pools and other. The cost of building any of these will depend on the specs you specify. Obviously, installing a swimming pool, state of the art cinema room or a kitchen will be more expensive than the cost of installing a gym.
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External Access
Do you require external access to the basement? This will add to your cost as a separate entrance and full access path will have to be excavated and created. It would be more cost-effective to have access from within the house, however, that may not always be desirable if, for example, your basement is going to be used for work (consulting rooms), where you don’t want your clients going through the house.
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Other costs
There are other costs you need to consider and factor in your overall cost of build. These are costs that are usually incurred even before a single stone is broken.
- Architect Fees – Please read our guide on Choosing the Right Architect.
- Planning Applications
- Structural Engineer Fees
- Building Regulation Fees – Find out about more about Building Regulations for Basements.
- Party Wall Agreements
- Insurance
A basement conversion can add valuable space to your property, however, it’s important to consider all the elements mentioned above when you are working out the costs. If you’d like a handy tool to help you plan your project, please download our FREE project management checklist.
If you’d like to have a look at some of the basements we’ve built (and we’ve done a fair few), please visit our Projectspage on our website.
And if you’d like to pick our brains on a basement conversion you are thinking about, please do not hesitate to get in touch. You can either book a FREE consultation where we’d be happy to pop around to your property and share some of our thoughts and recommendations or give us a call on 0208 191 7595to have a quick chat.
Read MoreYou can add valuable space to your home or property by building a basement. If you are thinking of creative ways of adding floor space in your home to incorporate perhaps a wine cellar or a home cinema or even a swimming pool, consider venturing downwards to the basement.
There are several structural regulations that must be adhered to when excavating below ground and these are areas that your architect and builder will take care of. However, one of the most important elements to consider is the waterproofing of your basement. One of the reasons homeowners are put off building basements is due to the possibility of flooding and leaking resulting in damage to furniture or equipment. Basement conversion waterproofing is therefore a vital decision in your conversion project.
We cannot stress enough how important it is to ensure your basement has a robust and hardy waterproofing system installed. Whatever method of waterproofing you choose for your basement conversion, it should be appropriate for resisting ground water pressure and should have British Board of Agreement (BBA) or similar independent technical accreditation.
One of the well-known waterproofing methods used by many builders is ‘tanking.’Tanking is a generic term used to describe various mediums which are used to deal with water entering a below ground building. Tanking membranes are really barriers which are applied to the structure to physically hold back water ingress and are the more traditional method of dealing with water from the ground. Tanking forms a completely waterproof box in the ground – like an inside-out swimming pool – but water pushing against a solid tanking barrier has a way of finding its way past or through in the end.
Today, most basement specialists use a more sophisticated cavity membrane system. This is a textured breathable membrane around the entire basement behind which any damp is trapped and channelled down the outside of the basement walls, under the floor and into a sump from where it is pumped harmlessly away.
As experienced builders with many years under our belts, the SDA Team have often been called in to fix many a botched project, and sadly one of the most common botches is poor waterproofing.
For this very reason, SDA Build London is proudly accredited by the UK’s leading waterproofing brand, Delta, with all our basement conversion projects installing their cutting-edge Delta Membrane Systems.
This high-density polyethylene covering is applied to the walls, floors and ceilings of a basement dig out, where it blocks, controls and drains any potential ground water ingress from entering a property. It can be applied to new, existing and retrofit projects, and is flexible and durable so it can cope with movement or vibration in the home – important as this is often the cause of basement flooding! All our Delta Membrane installations come with a 30-year warranty that ensures your basement is protected.
If you are building a basement and need some advice on waterproofing options, do give us a call on 0208 191 7595. Or simply book a FREE consultation via our website. We’d be happy to visit your property and share our thoughts on what might be your best way forward.
Read More