Danford Brewer & Ives are specialists in basement conversions and could give your home that extra space you need – even if you don’t currently have a cellar.

You can rest assured that Danford Brewer & Ives will have the whole job in hand, from the plans and structure design to accessing the planning permissions and having the building regulations passed, to the final lick of paint.

What Is a Basement Conversion?

If you’d love to expand your home but have little available space to do so, the best option could be a basement conversion. Instead of expanding horizontally, with a basement conversion you can utilise the space below your feet and make the most of the area underneath your property that would otherwise sit empty.

Basement conversions traditionally take a vacant, unused or dilapidated cellar, and turn it into a new, modern and liveable space. Even if your home doesn’t have an existing cellar space, it’s increasingly possible to excavate and underpin properties in order to create a new basement.

Why Should I Convert My Basement?

Basement conversions are a unique opportunity to extend your property below ground, but they offer much more than this. Basement conversions are a chance to create a quirky new living room, an exciting games room, a wine cellar, or a new bedroom or bathroom. Basement conversions also add value to your home, they can generate income if rented out, and more.

Here are some of the best reasons to add a basement conversion to your home:

  • Add an extra room to your property
  • Be creative with the new room and added space
  • Utilise unused space below ground
  • Save on garden space by extending down
  • Ensure the space below your home is well waterproofed, thereby protecting against damp and mould
  • Rent out the extra room for added income
  • Increase the value of your home

And what can a basement conversion be used for? This depends on the size of the space, but with the correct design and expert use of lighting, basement conversions have an impressive number of applications. A few examples to inspire your plans include:

  • A spare bedroom
  • A guest room
  • An entertaining room
  • A spare bathroom
  • A utility room
  • A games room
  • A music room
  • An office
  • A writing room

Basement conversions can be as exciting or as practical as you want them to be. Once the conversion is complete, you could install a complex record studio in the basement, or you could simply use the new space as a laundry or storage room.

What About Waterproofing, Lighting and Insulation?

In order for a basement conversion to be a truly liveable space, it must be thoroughly waterproofed, there must be adequate lighting and it must be well insulated. You want your new basement conversion to become an integral part of the rest of your home, so it’s important that all three of these factors are incorporated into the design.

Danford Brewer & Ives is able to prepare detailed designs for your new basement conversion that not only capture your imagination and plans, but create a functional, practical space complete with waterproof membranes, drainage systems, effective wall and ceiling insulation, and lighting systems.

How Long Do Basement Conversions Take?

The length of time it takes for a basement conversion to be completed depends on several factors. The most important factors are:

  • The size of the basement conversion
  • The complexity of the basement conversion
  • The extent of interior design work required

There are three major stages to any basement conversion project, which have to be factored into the timescale. These are the initial planning, surveying and design stage, followed by the excavation and building work that creates the space below ground or converts the existing space, and finally the interior design work.

The larger the basement conversion, the more time it will take to complete, but the length of a project also depends on its complexity. If there’s already an existing cellar space of a good size and shape, then little extra work may be needed to make it liveable. If lots of underpinning or excavation is required, this adds time (and costs) to the conversion.

Various Work Included in Converting Your Cellar:

Danford Brewer & Ives offers a full-service package when it comes to converting your cellar. Our team is here to help at every stage of the process, from design through to interior decorating. All of our work comes with an insurance-backed guarantee and is carried out to the highest possible standards by our experienced, professional team.

If you have a particular idea, design or style in mind, we are here to make it a reality. The primary work included in any project undertaken by Danford Brewer & Ives includes:

  • Excavation & Underpinning
  • Waterproof Membranes
  • Drainage Systems
  • Interior Finishes

Let’s take a look at this work and what it involves in more detail.

Excavation and Underpinning

Basement-Conversion-BeforeYou may think it’s not possible to make an extra room out of your cellar because of its low ceiling, or perhaps you don’t currently have a cellar at all. Danford Brewer & Ives can create a new, liveable space for you by lowering the foundation of your house through a method called underpinning.

Underpinning can extend existing foundations of a building by depth or width to either give a cellar more headroom where the current cellar is too shallow, or to create a cellar where there currently is none.

Danford Brewer & Ives will excavate soil from beneath the existing foundations, and fill most of this excavation with concrete. Once the concrete has settled, the remaining gap is filled with a sand and cement mix. This is carried out step by step to ensure the foundations are solid at all times.

A structural engineer will draw up the underpin schedule, and alongside building inspectors will inspect the work as it progresses, then approve it once the underpinning is complete.

Waterproof Membranes

basement waterproofing

Any basement conversions will need to be made waterproof. Danford Brewer & Ives ensures this by fixing a polyethylene membrane to the wall of the basement, which provides an air gap between the waterproof membrane and the wall, allowing any water to run behind it. The membrane is fixed to the wall with a framing system so that plasterboard can be fixed to it ready for plastering.

The high quality waterproof membranes that Danford Brewer & Ives use will stop dampness or salt problems, and also flooding where there may be harsh ground water conditions.

Drainage Systems

The water that flows behind and is controlled by the waterproof membrane system is diverted to a drain fitted around the basement. This water is then passed through to either a natural drainage point, or to a drainage sump fitted by Danford Brewer & Ives.

Interior Finishes

basement conversion finishes

Once the main structure of your new basement conversion has been completed, an aluminium frame with insulation is built around the converted cellar. When this is fitted, plasterboards are attached on to the frame of the basement, which is then plastered ready for the interior decoration.

When Danford Brewer & Ives has completed the job, you can rest assured that your brand new basement conversion will be well insulated, watertight, and built to the highest standard. If you are interested in having a basement conversion, please contact Danford Brewer & Ives on 01422 472547  for more information.

Insurance Backed Guarantee

At Danford Brewer & Ives, we work with trusted partners, meaning we can offer an independent guarantee to our customers upon completion of our basement conversions and timber treatments. Please contact us for details.

How much will it cost?

A typical basement conversion in the Yorkshire and Teesside area is usually in a Victorian terrace with an existing space in the basement. These basement rooms are usually cold, damp and badly lit. Provided the existing head height is adequate the price guide is between £700 – £1,300 per square meter. If the conversion works require any digging out, excavating or underpinning the work becomes more complex and more expensive. Underpinning usually costs between £1,500 – £2,000 per square meter.

To help you understand and get an idea of how much your basement conversion might cost we have provided 4 possible basement scenarios. Each one is based on 30m square of space below ground in a Victorian end terrace house.

Option 1. Simple Basement Conversion

This basement is a single room with 3 external walls and 1 party wall. The head height is more than adequate at 2.2m. The room is currently being used as a garden/ storeroom. In the winter periods, water appears to rise up through the stone flagged floor and is leaving the space continuously cold and damp. There is an existing solid stone staircase leading up to the main house and a small light well to the rear of the room.

Using a cavity drain membrane system, we will transform this space into a warm, dry storage area.

To achieve this we will install a perimeter drainage channel with flushing points at each change in direction. As there is no natural drainage present we will install a sump and pump with a high level battery alarm system. The drainage and pumps are fully maintainable and when combined with cavity drain membranes forms a waterproof structure to comply with current British Standards 8102 (2009) – The code of practice for protection of below ground structures against water from the ground. Your basement is now ready for the ‘fit out’ stage.

A new insulated timber floating floor will be installed and the walls lined with independent timber studs. The 1st fix electrics for the supply of a new socket and lighting circuit will be carried out along with plumbing alterations to add a new radiator. The walls and ceiling will then be plaster boarded and plastered to a finish. The electric and plumbing works will be finished and signed off as required. The basement conversion works are now complete and ready for decorating. As this space will only be used as storage Building Regulations do not apply and therefore insulation is not a requirement.


  • 4 walls, room area approx. 30m2
  • Cavity drain membranes to walls and floor
  • Drainage channel and mechanical pump system
  • Timber floating floor and studwork
  • Plasterboard and plaster finish
  • Electrics & Plumbing
  • Party Wall agreement
  • 10 year Independent, insurance backed guarantee.

Estimated Cost £ 26,250 + VAT (£875/m2)

Option 2. Standard Basement Conversion

A standard basement conversion would involve the same works as Option 1 with the addition of needing to have Building Regulations as the space is now to be used to provide an extra living space for the property. This will include the addition of insulation within the studwork and ceiling areas. There is also the inclusion of an internal load bearing wall that would require lining with cavity drain membrane and studwork.


  • 4 external walls (30m2)
  • 1 Internal (load bearing wall)
  • Drainage channel and mechanical pump system
  • Timber floating floor and studwork
  • Insulation
  • Plasterboard and plaster finish
  • Electrics & Plumbing
  • Party Wall agreement
  • Building Regulations
  • 10 year Independent, insurance backed guarantee.

Estimated costs £31,500 + VAT (£1050/m2)

Option 3. Complex Basement Conversion

A complex basement conversion has all the detail as standard basement with the addition of a more sophisticated pump system which includes a secondary pump with battery back-up. This type of basement conversion would also include digging out and creating a new external doorway with concrete access steps. Creating this opening would most likely require planning approval.


  • 4 external walls (30m2)
  • 1 Internal (load bearing wall)
  • Drainage channel and mechanical pump system with battery back up
  • Timber floating floor and studwork
  • Insulation
  • Plasterboard and plaster finish
  • Electrics & Plumbing
  • New external doorway with concrete steps
  • Party Wall agreement
  • Building Regulations
  • Planning permission fees
  • 10 year Independent, insurance backed guarantee.

Estimated cost £48,000 + VAT (£1600/m2)

Option 4. Complex Basement Conversion with Underpinning.

This type of conversion requires increasing the existing headroom. To achieve this the internal floor slab will be excavated to the required depth. The existing foundations will also require extending. This is done using a process called underpinning. With the help of our Structural Engineer, we can design and specify the detail required to carry out these works in a safe and controlled manner. Once the underpinning is complete the drainage and membranes are installed and the fit out completed.


  • 4 external walls (30m2)
  • 1 Internal (load bearing wall)
  • Drainage channel and mechanical pump system with battery back up
  • Concrete floor and studwork
  • Insulation
  • Plasterboard and plaster finish
  • Electrics & Plumbing
  • New external doorway with concrete steps
  • Party Wall agreement
  • Building Regulations
  • Planning permission fees
  • 10 year Independent, insurance backed guarantee.
  • Underpinning and excavation works

Estimated cost £95,000 + VAT

Do I need planning permission for my basement conversion?

Not necessarily. Converting a cellar from a storage space into a stylish new living space does not require planning permission, only a ‘Change of Use’.

What about building regulations?

Any basement that is converted into a new livable space will need to meet with Building Regulations. These ensure that the building is energy efficient, safe and hygienic.

If you have previously converted your basement to meet with Building Regulations, and are simply looking to renovate it; or you are repairing a cellar that will remain as a storage space, then they are excluded.

How long does a Basement Conversion take?

Simple cellar conversions generally take between 2 – 4 weeks.

Larger projects, for example, where underpinning is involved, could be considerably longer. Our site surveyor will be able to give you an estimated time of completion when he views the property.

Will there be much disruption?

Generally, you can continue living in the property if the ground floor is suspended timber and there is direct access to the cellar through a garden or driveway. This also allows for the efficient removal of any waste.

Will the basement be waterproof?

Yes. There are two different ways of making sure that your living space is kept dry.

Tanking – Tanking is used as a more traditional method to waterproofing cellars and can be used as an alternative to cavity drain membranes in certain circumstances.

Usually, this is a cementitious waterproof render system on the walls applied in several layers. These layers are linked to a waterproof screed floor.

Tanking is required to withstand the external water pressure around the basement. This pressure can be enormous and water will find any weaknesses in the structure, no matter how small, and can be very hard to repair.

Cavity Membranes – Cavity drain membrane provide an alternative to the cementitious systems and are designed to hold back, control and divert the water.

This is done by creating an inner structure behind the membrane where the water can flow freely, and where necessary, be drained or pumped away.

The membranes are designed to lay on floors and fixed using special plugs and sealants to the walls. This ensures pressure doesn’t build up against the internal structure and airflow is maintained allowing the structure to breathe, and in some cases dry out.

Once the membrane has been fitted the walls can be drylined or plastered directly. The floors can be screeded or a floating floor system can be used.

Am I restricted to have the basement under the footprint of my house?

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

Do I have to have an existing cellar or basement?

No. 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.

If you have a question that we have not answered please contact us.

Not only do Danford, Brewer & Ives offer expertise in the field of basement conversions to householders direct, we are also an ideal partner for builders, architects and property developers.

Perhaps the most likely scenario in this instance is the one in which a basement conversion is required as part of a larger project. If that’s the case, then sub-contracting that particular aspect of the work to us makes sense for all manner of reasons.

For starters, when it comes to ‘tanking’ a basement, we have proven expertise – meaning that the work will be undertaken skillfully and efficiently. As a consequence, therefore, a partnership with us should also be more cost-effective.

Furthermore, such an arrangement would also leave you free to concentrate on your own particular strengths. In fact, it might conceivably be the case that pooling resources in such a way enables both parties to win the sorts of work neither might otherwise secure.

The priority, of course, is the customer, who will have all the necessary guarantees – not to mention peace of mind – thanks to a company with our track record on board.

Working with us offers independent, insurance-backed guarantees, while projects that include basement conversions may require Danford, Brewer & Ives’ specialist waterproofing skills to meet the needs of warranties such as the NHBC (National House Building Council).

Finally, it’s a relationship we understand, since we already have extensive experience of working with builders, developers and architects to prepare basement conversions for the ‘fit out’ stage.

As always, if there is something that we have not managed to address and you would like to speak with a member of the team, please do not hesitate to contact us today.

Cellar conversion before
Basement-Conversion After

There are many advantages in hiring Danford, Brewer & Ives as a sub-contractor on projects that include a basement conversion:

    • It allows builder/architect/property developer to focus on their own strengths, safe in the knowledge that they are working with proven experts in the field.
    • Pooling skills and resources in such a way should prove cost-effective. We provide an all-inclusive price that can then be easily incorporated into the client price.
    • If the builder/architect/developer does have limited experience of potential issues that can arise when undertaking basement conversions, we offer specialist advice at an early stage including a site survey and project assessment.
    • We also offer attention to detail: in the subsequent analysis, a specification would be developed and finer points agreed with the architect to include in their design.
    • We can assist developers to make the best possible use of available space and land.
    • Hiring us enables the opportunity for both parties to win business they might not normally otherwise secure.
    • We offer independent insurance-backed guarantees, as our design specification and guarantees may be required to meet the requirements of NHBC (National House Building Council) or similar warranties.
    • It’s a relationship we know well: we already have extensive experience working with builders, architects and developers, and are well-versed in working our schedule into the overall schedule of works.

1. “Can we?” “Can’t we?”

Every basement conversion starts with a few questions.  Can we have one?  How long will it take?  How much will it cost? (Contact us for more information)  Once you have considered having a cellar conversion, it is time to speak with the experts and invite one of the Danford Brewer & Ives site assessors to visit your property.

2. Site Survey

Danford Brewer & Ives will arrange to visit your property at a convenient time to carry out a site survey and project assessment.  During the meeting, we will discuss what you want to achieve from the project, how you would like the space to function, what the practicalities of the project would be, and to talk through any potential challenges you may face.

The site surveys usually take about an hour, and at the end of this meeting, or shortly afterwards, the site assessor will be able to give you an approximate verbal price.  Allowing you to better understand what the project is likely to cost and what you will need to budget for.

3. Written Confirmation

Following our initial meeting we will write to you confirming what was discussed, an explanation of what you are looking from the project and an indication of what the next steps should be. For a straightforward basement conversion, we will be able to provide an accurate quotation to complete the work.

In some cases, it is necessary to appoint an Architect or Structural Engineer to draw up more detailed plans for the project. We work with several architects and structural engineers, so if further advice is required we will confirm what exact price will be to employ their services.

4. Appoint an Architect / Structural Engineer

In the event that further advice is required, we will appoint one of our trusted partners to carry out the work. Once they have drawn up the plans we will then meet to discuss the project in more detail. During the meeting, we will discuss the project, the finish, timescales, and specifications. We will then provide you with an accurate project cost in writing.

5. Accept Proposal

You will now know what the project is going to cost. If you would like Danford Brewer and Ives to carry out the work, we would just need an initial deposit from you. We would confirm when the work would start and an idea of what the project stages and how long each of them would take.

6. Schedule of Works

Once you have confirmed that you wish the project to start we would send you a Schedule of Works, which outlines the project detail, offers a realistic timeline of events and explains what the next steps will be.

We have built our fantastic reputation by having great communication with all our clients, so if at any point you would like a progress report or would like a part of the process explaining in more detail, then please do not hesitate to contact a member of our friendly team.

Converting your existing cellar into a useful below ground space isn’t too difficult or costly to achieve. Danford Brewer & Ives have the experience and can provide you with all of the information you need to decide whether a basement conversion is possible at your home.


Whether you need more space for your expanding family, a functional office or additional guest rooms; cellar conversions provide that extra living or storage space you require. Whatever basement space you have, we can convert your damp, dark, wet and flooded basements in Yorkshire, North West and the North East into fantastic versatile spaces.

Just think of what you could do by converting your basement or cellar; you could have an extra bedroom, have the office or study you need, or some additional space for the children to play in, you may even want to use the new space as a gym. Whatever the reasons are for needing more space, a well-designed basement conversion is an ideal way to utilise the space you already have but aren’t currently using.

The following pages have been written to talk you through the whole process so that you can make an informed decision whether or not to pursue a basement or cellar conversion.

As always, if there is something that we have not managed to address and you would like to speak with a member of the team, please do not hesitate to contact us today.

Basement Conversion Before

In April 2015, Danford Brewer and Ives were contracted by John Walsh from 101 Construction. John is the owner of 101 Construction, based near Bradford and was pricing for a job in Ripon, North Yorkshire, which involved correcting a basement conversion and extension recently completed by another builder. The project brief was to provide a spacious kitchen opening onto a lowered garden area. In addition, inside two further rooms were created, a fully tiled shower room and new open stairs were all installed to modern design.

The original builder had ignored recommendations to provide a proper cavity drainage system which would fully waterproof the below ground areas. Instead, the builder cobbled together a mixture of land drains and liquid coatings, which was a completely unsuitable tanking solution for the property. As the original works neared completion it became obvious that the ‘tanking’ wasn’t working, the new areas started to show signs of damp and then, after heavy rain, standing water appeared across the floors. This resulted in a lengthy and expensive dispute between the client and the original builder.

Danford Brewer & Ives, who are experts in basement conversions, were asked to provide a design for remedial structural waterproofing works. We met with 101 Construction and over the next few weeks considered various options and costs. We wanted to provide a system that was guaranteed, and one that would comply with British Standards 8120:2009. We were also aware that this was a sensitive situation as it would mean we would have to strip out everything that the client had just paid to have installed.

It became clear, following further heavy rain, that the property needed a maintainable cavity drain system, consisting of wall and floor membranes and perimeter drainage channels which lead to a below floor sump with pump. A backup pump and alarm system were also essential. John discussed this news with his client and agreement was reached to proceed.

In July 2015, 101 construction removed the newly installed kitchen and staircase, broke out concrete floors, removed wall plaster and prepared the room for us.

We installed the sump, pump and drainage channels which 101 Construction connected to a suitable drain. We then fitted and sealed a cavity drain membrane to the walls and fitted it around windows and the steel posts. A larger capacity membrane was then laid over the floor which was then sealed into the wall membrane. Throughout this process, we worked with and co-ordinated the other tradesmen to ensure their services were sealed where necessary.

This entire process was completed within a week so that the refitting could continue without further delay.

The rooms have now been reinstated and can, at last, be used. The winter of 2015/2016 has been one of the wettest on record and the pumps have been busy keeping the water out, we recently serviced the system and the clients have decided to change the backup pump for a battery system that will continue to work even during power cuts.

The entire waterproofing system comes with a 10 year independently backed insurance guarantee.

“Danford Brewer & Ives, provided 101 Construction with invaluable support during and after the Ripon project. Their expertise in damp proofing ensured that our client was able to have the living space they had dreamed. We will certainly work with Danford Brewer & Ives in the future, and would have no hesitation in recommending them to other building companies who want a professionally installed and insured damp proofing system” – John Walsh, Owner, 101 Construction


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The Effect of Wall Insulation on Energy Efficiency