Cellar Conversions: Considerations, Cost & Regulations.

Cellars are rooms below ground level in a house that is often only used for storing wine or coal; it is used for a specific purpose.



A cellar is often a small without the benefit of direct sunlight and with cooler temperatures cellars are more often used as general storage areas – for example wine storage. In this article we help you answer the question, How much does a cellar conversion cost?

Converting your cellar is a smart investment. It is an affordable way to expand your living space and it will likely increase the value of your property. There are lots of different reasons to convert your cellar; some people might want an extra bedroom or a new bathroom, others might want a cellar office conversion or even a cellar gym conversion.

Not all building land is suitable for the development of a basement. And anyway, a dwelling house does not necessarily have to be excavated. What are the arguments for or against a cellar?

Companies specialising in cellar construction tend to underestimate the workload. Some expect "only 10% additional costs" for a basement, this supplement being calculated on the basis of the budget total construction. But it will quickly be understood that the effective workload for a cellar involves a few expensive work steps. In particular, the excavation should not be underestimated. Similarly, the basement envelope must be provided with a layer thermal insulation suitable, preventing the formation of condensation.

In terms of the building envelope, the shell of a basement is hardly cheaper compared to that of the upper floors. In urban areas, apart from underground parking lots, basements are hardly ever made. From this perspective and, having regard to the costs, one could generally consider that the construction of a cellar is useless: do we really need as much space to store tires, sports equipment or clothing? 'Winter? Even for heating, it is now recommended to set up a room on the ground floor. Indeed, this makes it possible to optimise its performance, because the pipes are thus shorter.

So what are the arguments that continue to plead in favour of the excavation of residential houses? 

Cellar conversion benefits:

Additional Space

Even an unfinished basement can add convenience to your daily living by increasing the amount of storage space. Over the years, it’s easy to build up your collection of recreational equipment, holiday décor, and the odd memorabilia. With a basement, you can create an organized storage space where all of your precious items are easily located and accessed. Additionally, the basement is a perfect place to store backup food storage and other canned goods that can become cluttered if kept in your normal living space.

Added Privacy

Basements allow for a stunning in-law or guest accommodation. If you frequently host guests or have family members stay for extended periods of time, there are few better options than a private suite in the basement. Your guests can enjoy privacy and independence during their stay.

Additional Bedrooms & Bathrooms

For growing families, the basement can be the perfect solution. You could, perhaps, purchase your home with an unfinished basement, giving you the potential for more square footage. Then, when you welcome new members to your family, you can add more bedrooms and bathrooms to accommodate.

Increased Home Value

Until your basement is finished, the square footage isn’t considered “liveable” and therefore isn’t considered during a resell. However, if you decide to finish your basement, you’ll enjoy a great return on your investment. In fact, the average basement remodels returns 70 to 75% of your investment. And you get to enjoy the added space, too.

Recreational Space



We love the kids, but sometimes it’s nice when they can rough-house away from the main living space. Recreation rooms are perfect for the basement! You can store toys and a second T.V. for the kiddos to have their own, personal spot to play. If your family is a little older, the basement can be the much-needed space to partake in other hobbies like woodworking, yoga, board games, or a game of pool.

Whatever your family enjoys, the added space will make the activity more fun and less of a burden on the main living space. To see the floorplans for new homes offered by Hamlet Homes that include basements, visit our community pages or call one of our expert sales representatives. We can go over all your options and find the right new home for you and your family.

If you are thinking of having a cellar conversion, you will need to find out if your cellar is suitable. By organizing a cellar survey you will be able to get an expert to analyse your possible options, figure out any potential obstacles and inform you of the waterproofing regulations your cellar would need to adhere to. Our structural waterproofing experts will offer you a better insight to the work required to make your cellar conversion dreams a reality.

Preparing Your Cellar For Conversion



You will need to clear out your cellar completely. It is likely that extensive work will need to be done to turn an unused cellar into something special. Also, depending on the height of your cellar, you may need to excavate the floor to increase the height. Lastly, you may need to strengthen the foundations of your property to make your cellar safe for habitation.

Waterproofing your cellar before conversion



This is by far the most important step in any project. If your cellar is not sufficiently waterproofed, water will find a way in; and water ingress has the potential to ruin any upholstery, carpets, wallpaper, and decorations you have in your new cellar.

In most circumstances, we would recommend a modern internal water management system for a cellar. These systems will channel water as it enters the cellar and disposes of it safely. To find out more about cellar waterproofing visit our dedicated web page

A basement conversion can be an effective way to make the most of your current space. However, they’re not for everyone. It all depends on your property, your budget and your ambitions. For example, converting an already existing cellar is going to be significantly cheaper and easier than excavating a basement from scratch.

While enjoying the newly created space may be a secondary benefit to adding value to your home, it’s important to remember that there is a ‘ceiling value’ to most properties. This value can be near impossible to surpass, no matter how extravagantly your new basement conversion may be.

Whatever your plans and whatever your budget, it’s crucial that you employ the expertise of local estate agents when assessing the viability of investing in a basement conversion. (Enter your postcode here to find the best local estate agents in your area).

In general, basement extensions are far cheaper when no excavation is required – either to create the underground space from scratch or to extend the headroom of an existing basement or cellar. Cellar conversions roughly cost half as much as building a completely new basement. 

If you have no existing underground space and you’re creating a basement entirely from scratch, you can expect to pay between £3,000 – £4,000 per square metre. A large portion of the costs relate to the necessary groundwork: this includes excavation and underpinning the property’s foundations, as well as plumbing, lighting, damp-proofing and ventilation.

Other factors that may contribute to basement conversion costs include:

·      Incorporating an external access 

·      Architect/surveyor fees

·      Planning permission application fees

·      Building regulations application

·      Party Wall agreement