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Yes and no. If you already have a basement you often won't need planning permission for the conversion. However, if you need to add an entirely new one, it’s likely you’ll need permission before getting started.

How to tell if a basement conversion is to regulations

The best way to check this is to hire a professional to assess your basement conversion.

The amount you pay for your cellar conversion will vary depending on a number of factors. If you’re wondering how much a basement conversion costs, consider the following variables:

• Size of basement - The larger your basement is, the more you’ll pay for it to be converted.

• Conversion or excavation - It’s more expensive to build a new cellar than convert an existing cellar.

• Structural support - If your home needs additional structural support in order to secure your basement, this will be an extra cost.

• Cellar purpose - Depending on how you plan to use your new basement, the conversion price may vary. For example, a wine cellar requires much less work than a home gym or swimming pool.

• Utilities - If you plan to add power, gas, plumbing and air conditioning to your basement, this will increase the conversion price.

• Materials used - Choosing higher quality materials will make your basement look incredible and last for years to come but they’re more expensive than basic materials.

Basement conversion cost

Ok, let's look at the average cost of a cellar conversion. Bear in mind that the above factors will affect how much you pay. However as a rough guide, the average cellar conversion cost is £1,400 per square metre. If you need an entirely new basement to be excavated, the average cost of a cellar conversion will be closer to £2,280 per square metre.

For more prices, tips and information, visit our cellar conversion cost guide.

How much does it cost to finish a basement?

Once the essential installation work has been completed, you can move onto finishing your basement. The amount you need to budget for this stage will vary depending on the scope of your plans. Having said that, the average cost of finishing a basement is £1,100 per square metre. You can find more information in our guide on the cost to finish a basement.

If you’re planning a basement conversion, it can be tempting to do the work yourself. However, this project is neither quick nor easy. Unless you have sufficient experience in cellar conversions, we’d recommend leaving the work to a professional.

If you’re curious about the process of a basement conversion, we’ve summarised the steps below:

• If necessary excavate your basement

• Install any additional support if needed

• Add a waterproof membrane to the space

• Fit utilities

• Install flooring and plaster the walls

• Add heating and lighting

• Decorate and furnish the space

You can find more information and advice in our guide on how to convert a cellar.

Basement waterproofing

A key step in your cellar conversion project is waterproofing the space. Our basement waterproofing cost guide is bursting with helpful information including prices and factors to consider. The average price of waterproofing a basement is £120 per metre squared.

Lowering a basement floor

Converting a small area into a living space requires many changes. One of these is to increase the headroom of your cellar. You can do this by lowering your basement floor. If you’d like to learn more, check out our lowering a basement floor guide.

Want to speak to a basement conversion company in SM3?

No problem, we can help you to find cellar conversion contractors in no time at all. Our members pass thorough checks to ensure they have the right experience and qualifications to surpass your expectations. They’re even recommended by your neighbours.

There are two ways we can help you find cellar conversion experts in SM3. Firstly, our free search feature is a great way of locating local basement conversion builders. Just enter your postcode and we’ll show you a range of professionals in your area.

Alternatively, our request a quote feature is perfect for busy homeowners. Fill in our handy online form with the details of your job. We’ll then forward this to three cellar conversion companies who’ll contact you with personalised quotes. It really is that easy.