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Basement Conversions

Building Services / Conversions / Basement Conversions

Basement Conversions Cardiff & South Wales

We undertake high quality basement conversions in Cardiff, from design and planning through to completion.

Professional and bespoke basement conversions.

Convert your basement into a usable room that will help you get the very best out of your home's potential.

Our basement conversion services can help you realise your property dreams, while also adding significant value.

We conduct garage conversions and other home conversions in Cardiff and surrounding areas of South Wales on a regular basis, therefore our team of specialist builders and tradesmen are some of the most experienced available in this location.

100% bespoke design and planning

During the design and planning stage, our team will work closely with you so that we can ensure the finished result is a basement conversion that meets your every need. We'll be there to offer our expertise from the very beginning right through to completion.

Specialist modifications

A vast choice of specialist modifications can be included within your basement conversion plans, allowing us to convert your space into a room that caters to your every need.

The basement is usually an area of the house that receives very little light.

Things such as skylights, sun pipes and light wells offer a range of different ways to help light enter the basement conversion.

The list of optional modifications is extensive, allowing you to decide between keeping things basic or running wild with your creativity and imagination.

Full project management

We set ourselves incredibly high standards, and plan to maintain and build on these with each basement conversion we undertake. For this reason, our complete project management ensures your project always receives the close attention to detail it deserves.

Create A New Space With Our Expert Basement Conversion Service

RGB Construction - experts in Cardiff basement conversions.

Our vast experience allow us to offer you a complete design and build package that will bring your vision to life.

Why Choose RGB Construction For Your Cardiff Basement Conversion?



...tailored to your every need.



...such as skylights, sun pipes and light wells.



...with a dedicated team of experts.



...and backed with full insurance.

A basement conversion can transfer a forgotten room into something special.

  • Additional Lounge Area

  • Entertainment Room

  • Utility Room

  • Gym

  • Home Cinema

  • Play Room

  • Lower Floor Kitchen Diner

...your imagination is the only limit.

Basement conversion in a property in Cardiff
Basement conversion in a property in Cardiff
Basement converted into a kitchen diner in a property in Cardiff
A basement converted into a cinema room in a property in Cardiff

Benefits of Converting Your Basement

A basement conversion is a luxurious solution to a shortage of space in a property - a perfect way to add valuable space to your home when accommodating a growing family.

There are many basement hotspots across Cardiff, but many properties fail to make full use of the available space that sits below the ground floor. A basement conversion will create a useful new environment for a growing family, from a spacious kitchen diner to an alternative place where you can either kick back and relax or get fit and active in a home gym, the opportunities are simply endless.

Regardless of how the economy is faring up, basement conversions are always a sensible choice. This is because enhancing and increasing the living space within your current property will almost always prove far more viable and less expensive than selling up in order to purchase a larger home.

It is also estimated that embarking on a basement conversion project can add as much as 15-20% to the value of a property, so when the time to sell does arrive you'll be ready to reap the financial rewards on your home improvement investment.

Are you ready to discuss your basement conversion project?

Contact us today with details of your requirements to book your free no obligation quotation.

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Basement Conversion Enquiry

Basement Conversion FAQs

Basement Conversion FAQs
What can I expect from your design and build basement conversions?

What can I expect from your design and build basement conversions?

Our expertise will allow us to bring your vision, ideas and requirements to reality. From the very first stages of designing and planning your basement conversion, through to the completion of the project several weeks later, our team will be there to project manage the entire process and ensure everything remains as stress-free as possible for you.


We will be there to answer any questions you may have along the way, and will remain fully transparent throughout so that you are kept fully up-to-date with the progress of your fantastic new basement conversion.

How long does it take to complete a basement conversion?

An accurate answer largely depends on the size and complexity of your basement conversion project. During our initial discussions we will be able to provide an estimation of the expected construction time, and we always seek ways to reduce our onsite time wherever possible provided there is no loss of quality in the final result.


As an example, a small and very simple basement conversion may reach completion within as little as 4 weeks.


A standard basement conversion is more likely to take anywhere from 12 - 24 weeks, dependant on the size of the area and the extent of the works that need to be carried out.

How much does a basement conversion cost?

We aim to provide exceptionally good value for money, and strive to offer the highest quality basement conversion services. However, it is difficult to provide a ballpark figure on costs because each conversion project will vary in size and application.


If you have a budget in mind, then we are able to survey the potential possibilities that we may be able to construct within that priceframe.


There are many variable involved when creating a personalised quote for your bespoke basement conversion, ranging from the amount of structural work that's required, access to the location, ground conditions, local authority charges, personalised specifications or modifications and much, much more.


It is a very complex question to answer and we regret that we can't be more specific. We do offer a free no obligation quote, so we would be more than happy for you to contact us to book an appointment where we can call in and discuss your requirements in more detail.


Whatever your budget and whatever your requirement, we thoroughly enjoy doing all that we can to make it happen.

Why should I convert my basement?

Instead of using valuable land and garden space around your property, a basement conversion provides an entire new floor level of usable space that can consist of one, two or several room for a multitude of purposes. Examples include home office, home gym, home cinema, additional bedroom or granny annex, kitchen diner, lounge space, or even an indoor swimming pool or sauna. The choice is limitless.


The cost of moving can also stack up, and when you compare the alternative - which is converting existing space within your current property - it is often a far more feasible option.

Not only this, but a basement conversion is also very likely to add significant value to your property. It really is a fantastic home improvement project that creates additional usable space and proves a lucrative financial investment.


Basement conversions aren't just for large growing families, either. You may have dreamed of adding something luxurious to your property for years - perhaps a snooker room or bar area where you can entertain guests. This may be your opportunity to really put a stamp on the property you love, allowing you to enjoy it for many more years to come.


Do I need planning permission to convert my basement?

In the majority of cases a basement construction does not need planning permission. This is because a basement conversion doesn't usually change the external appearance of the building. However, this will vary depending upon your local authority.


If you live within a conservation area, you may find that you need to negotiate with your conservtion officer to ensure the proposed plans are within current guidelines.


If you are planning on creating a self-contained dwelling, then you will need permission.


Planning permission is also likely to be required if additional visible windows and doors are to be added.


We will be there every step of the way to guide and advise you on any potential planning implications, and will highlight any areas that need addressing during our initial discussions.


Do you only carry out basement conversions in Cardiff?

We carry out basement conversions across Cardiff as well as the surrounding areas of South Wales.


I have a basement but head height is limited. What should I consider?

The first things to consider are whether the property is detached, semi-detached, terraced, an apartment, freehold, leasehold...?


Then consider:


  • Approximate size of the existing basement.

  • The purpose of the basement conversion and what the current state is.

  • Construction of the walls, floors and ceilings. (brick/stone/concrete?)

  • Existing and proposed plumbing and electrical services.

  • Current floor to ceiling height, and what you'd like it to be.

  • Available access routes in and out of the property.

  • History of the space in respect of any water penetration; is it damp, wet or in good condition?


Once you have considered these things, you will be well prepared during our initial discussions. It will allow us to accurately estimate a budget for the proposed basement conversion and equip you with any extra information that you should be aware of.

Does there need to be an existing basement?

There is no need for there to be any existing basement for us to construct one for you. It certainly helps, but if one doesn't exist we can simply excavate straight through the ground floor.


Another option is utilise any space that may be available at the front or rear of the property. Here, we could dig straight down, cut through the foundation and then structurally underpin the walls above as we go.


Feel free to get in touch with us if you'd like to add a basement room to your property, as we'd be more than happy to discuss the possibilities that are available to you in more detail.


Do you have the relevant accreditation?

Yes, RGB Construction are members of the Federation of Master Builders (FMB).

Will my basement conversion come with a guarantee?

Yes, your basement conversion will come complete with a guarantee.

How long does it usually take to complete a basement conversion?
How much does a basement conversion cost?
Why should I convert my basement?
Do I need planning permission to convert my basement?
Do you only carry out basement conversions in Cardiff?
I have a basement but head height is limited. What should I consider?
Does there need to be an existing basement?
Do you have the relevant accreditation?
Will my basement conversion come with a guarantee?

We cover Cardiff and surrounding areas of South Wales.

We'd love to put our expertise to use and help design and create the perfect basement conversion for you, so don't hesitate to get in touch with us today.

A map of the area in Cardiff and South Wales that RGB Construction undertake building services

As well as building quality basement conversions, we also enjoy writing about all things building and construction.

Our news page is where we keep our latest news, tips and building related information.

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