Basement Conversions

The Ultimate Guide to Basement Conversions

Guide to Basement Conversions By Experts

An increasing number of people are converting or installing basements to make more space in their homes.
In most cases, basement conversions have a positive impact on the value of the house, which makes them even more desirable. However, installing or converting a basement is a significant project that requires a fair amount of planning, considerations, permissions, and money.
To help you take on this challenge, the Danford Brewer & Ives' basement conversion experts have shared their ultimate guide to basement conversion:

Your Ideas

When planning to add a basement room to your house, you must have an answer to some crucial questions, including the reason, the worth, and the time duration of the conversion or installation. You may need to consult a professional to get an answer to your questions.
Firstly, you need to decide on the use of the basement room that you are planning to build. Are you going to use it as a spare bedroom? Will it be a leisure space or an extra bathroom or kitchen? All basement builds irrespective of the intended purpose come with challenges, which you need to be prepared for in advance.
You should also make sure that the basement conversion or installation will add value to your property and look at the return on your investment because you would not want your money, time and effort to go to waste if you eventually plan to sell the property.


After you have decided the purpose of the basement room and considered the return on your investment, then you can go on to evaluating other, more specific aspects of the room, which include:

  • Waterproofing

Waterproofing, alongside any structural changes, are the most significant considerations for basement conversions and basement installations. Because they are below ground level, basements will be subject to groundwater and some may be below a water table or a perched water table. Protection of below ground structures against water from the ground is fully explained in British Standards 8102:2009. It is very important that this standard is followed in any basement conversion or new build. These rules will ensure that a correct method of tanking or water control is used. Basements are often more vulnerable to condensation and adequate insulation, ventilation and heating will be necessary.

  • Lighting

Understandably, basements will not have a lot of natural light so you will have to consider how you will adequately light up the area using artificial lighting and light reflecting colours. Another way by which you can increase natural light in the basement is to add a sunken garden, which will increase the cost of the project.

  • Bathrooms

If you intend on using your basement conversion as a spare room, then it is likely that you are going to add a bathroom for washing up. If a bathroom is in the plan, consider the ventilation, the type of toilet you will use and the plumbing.

Financial Planning

As with all construction projects, you need to plan the financial aspect of the basement conversion meticulously, ensuring that you stay within the budget. Start by contacting the professionals for quotes and plan your budget accordingly.

Building Permissions and Regulations

Often a straight forward cellar conversion will not require planning permission, but checks must be made and Building Regulations will apply. Some changes to form new windows and doorways may come under permitted development and not need full planning consent, but major changes to the appearance or change of use should always be checked before any work is started. An architect of the local planning authority should give the best advice. An experienced, qualified contractor should be aware of the rules and regulations.

Look For Basement Conversion Professionals

Once the planning, financing and permission aspects are completed, you can then start looking for professionals that are reputable and can provide you with high-quality solutions for basement conversions within your budget. Do your research, read reviews and meet with the professionals before the selection. Remember to comply with British Standard 8102:2009 and all relevant Building Regulations.
Danford Brewer & Ives are basement conversion experts.  With many successful projects completed, we are the perfect partner for anyone looking to have a basement conversion.  To discuss your plans further simply contact DBI and book an appointment for one of our qualified site surveyors to visit you and run through the options with you.


Basement Conversion Considerations

Top 6 Considerations to Keep in Mind before You Start Basement Conversion.

You might have dreams of building your dream cinema to enjoy Saturday nights with your friends at home, or you might be thinking about taking your passion to the next level by building a gym Basement-Conversion-Afteror a music studio in your basement.

If you want to make the most out of your basement by converting it into a more useful space, then make sure that it is not an impulsive decision. Make sure that you go through our list of considerations that you should keep in mind before starting with your basement conversion project.

1. Consult a Professional before Starting

You might be excited and all pumped up to start a conversion project as soon as possible; however, it is essential to consult a professional to ensure that your house’s structure allows you to dig into the basement or not.

It is necessary to know how deep you can go into the ground because not all homes are built with a basement plan. So, rather than starting a project impulsively and regretting it later, you should consult an experienced architect, engineer or contractor and discuss the possibilities with them.

2. Don’t Miscalculate Your Budget

Once you start a basement conversion project, you cannot leave it halfway. Make sure that you get all the estimates from professional, experienced builders to avoid miscalculation. You cannot afford any miscalculation, thus consult a professional to ensure that you know how much money you would need to complete a project. Make sure that you keep a surplus amount just-in-case.

3. Get Legal Permission

Make sure that you consult the legal authorities to know whether you have legal permission for a basement or not. Checking if you need planning permission from the local authority is essential, as is compliance with Building Regulations and The Party Wall Act.

A company experienced in basement conversions would be able to guide you about how much time it requires for you to get legal permission and what terms you will have to agree with according to the legal agreement.

4. Make Sure That It Is Water-Proof

If your property is located in an area where the underground is usually damp, then you need to get help from a professional, ensuring that your basement is dry. Making sure that your basement is waterproof will help you protect your house from structural damage.

It doesn’t matter if you are planning to make a music studio or even a swimming pool, you need to ensure that your basement is completely waterproof.

5. Sufficient Lighting

Depending on the possibilities, you need to make sure that you make all efforts for maximum natural lighting in the basement. Moreover, if you have planned to convert your basement into a living area, bedroom, annexe, or a kitchen, then natural light will provide the basement with a refreshing environment, making it more welcoming.

6. Décor is Important

It is a horrible idea to overload your basement with furniture and decorative items. Basements are already considered dark and dingy; so overloading it with furniture will not be a good idea when looking for basement conversions. Thus, you should focus on keeping it simple and fresh.

Danford Brewer & Ives are basement conversion experts.  With many successful projects completed, we are the perfect partner for anyone looking to have a basement conversion.

To discuss your plans further simply contact DBI and book an appointment for one of our qualified site surveyors to visit you and run through the options with you.

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Benefits of Basement Waterproof Tanking Systems

The different methods of waterproofing a basement and benefits of basement waterproof tanking systems

At the time of writing, it is getting colder and the rain can be incessant. Spending time in a cellar
might not, therefore, hold much appeal. One might venture down there to rummage for the
Christmas decorations, notice the damp and the wet, shrug, then head back upstairs thinking of
festivities warmed by log fires and the odd tipple.

That’s Christmas. But what about the New Year? Resolve, resolutions and renewal? Maybe; maybe not.
Yet it’s as good a time as any to consider how converting your cold, damp cellar might offer more
living space and, for the investment, a proportionally greater increase in property value.
In a climate such as ours, a damp cellar is a fact of life: without protection – in older buildings, say,
with floors built from rough slabs, stone or brick – hydrostatic pressure will result in water ingress.
Soil-retaining walls will be vulnerable – particularly where the cellar floor joins the wall – and, at best,
the cellar will only be suitable for basic storage (so remember not to park those decorations too
close to the walls).

It’s self-evident why tanking is named so: in effect, a waterproof tank is created. However, its job is
to keep the water out not in.

There are three methods of waterproofing a basement, they can be used separately or sometimes together:

A) Barrier protection. This process relies on an unbroken ‘monolithic’ membrane to keep
moisture out. It is achieved by applying different impervious coatings – cement renders,
slurry, resins, bitumen-based products, spray on systems and bonded sheets – to the existing
floor and walls.

B) Structural integral protection. In this method, the structure itself (waterproof reinforced
concrete) is the protection. This method might be used when constructing a new basement,
usually in combination with A or C, to meet new building warranty requirements.

C) A cavity drain membrane (CDM). This works by placing the drainage on the inside of the
structure, between it and a plastic membrane. Water then drips down the outside of the
membrane, gathering in a drip tray-style drain before it flows to a sump pump and then an
external drain.

We will discuss cavity drain membrane (CDM) some more, since not only is it our most popular solution, it is also the cleverest and, arguably, the most effective.

For starters, a CDM prevents a gradual pressure build-up against the construction. With options A)
and B), it would be necessary to dig drainage on the outside of the tank. With option C), however,
the drainage is on the inside; the moisture’s progress is halted by the plastic membrane. Moreover,
the air gap allows the structure to ‘breathe’ and dry out.

The membrane is usually a high-quality, high-density plastic such as polyethylene. It will be studded
in appearance – allowing water to drip down to the drain – and comes in various thicknesses e.g.
3mm, 5mm, or 8mm, and up to 20mm for the floor membrane. It will also be gas and vapour-proof
and will have a long-lasting guarantee e.g. 10 years. It is applied using sealed, fixing plugs.
The drainage channels are created around the basement perimeter, leading to the sump chamber,
while floor insulation will first be applied to offer maximum resistance to ground moisture
penetration before a floor membrane is laid for added waterproofing.

Where the wall membrane meets the floor membrane, vapour tape is used. In this way, a secure
moisture barrier is placed over the seams and it also strengthens the joins, keeping the membrane in

The sump pump, meanwhile, is installed at the beginning of the process i.e. when only the basement
shell exists and before the membrane is applied. It is fitted in the sump chamber – the lowest point
of the basement – and connected to the drainage channels underneath the membrane walls. The
groundwater is then pumped out to an external drain.

With a lid on the chamber, the screed will be laid over the floor membrane and, depending on the type
of membrane used, plaster might be skimmed on to it directly.
Another solution is ‘drylining’, in which metal or wooden framing is fixed to the membrane, allowing
for a drywall finish. After that, the basement may be ‘fitted out’, with electrical and plumbing
fixtures added.

The work is always done in accordance with BS8102- 2009 – the code of practice for protection of
below ground structures against water from the ground.
At this point, the waterproofing would be completed. However, if the work were part of a larger
project, Danford Brewer & Ives might hand over to a partner e.g. a builder, architect or property

If, for example, we were assisting a property developer, we might advise them on making the best
possible use of available space and land. It might also be necessary, say, to provide underpinning if
the conversion of a basement compromises the structural integrity of the property by weakening the
foundations or removing walls.

The potential offered by tanking is enormous. And by making use of our expertise (Danford Brewer
& Ives are qualified surveyors with both CSRT (Certificated Surveyor in Remedial Treatment) and
CSSW (Certificated Surveyor in Structural Waterproofing) credentials) both householders and
building partners can gain significant living space and add value.

Moreover, we are skilful, efficient and cost-effective. If you would like more information on tanking,
structural waterproofing or any of the other building services Danford Brewer & Ives offer, such as
timber treatment, extensions or building maintenance – then please contact us. As always, we’re
more than happy to help.