Will I Need Planning Permission to Convert My Basement?

If you extend your home with a loft conversion or a conventional extension, the chances are that you will have to get planning permission. But does the same apply to basements? The answer depends on what you’re planning to do.

Existing Basements

Converting an existing basement or cellar into living space is, in most cases, not likely to need you to get planning permission provided the area of the extension is less than 70 cubic metres (50 cubic metres for terraced properties). However, there are some times when it may. If you’re planning on making the basement into a separate self-contained dwelling, or if the conversion work will change the external appearance of the house, such as adding windows or a light well, then you will require permission.

If you have a listed building or you live in a conservation area, then you will require permission even if the external appearance of the property isn’t changed. If you’re unsure if permission will be required, it’s best to contact your local council’s planning department for advice.

Although you may not need planning permission, you will need to ensure that the work complies with building regulations. These cover things like ventilation, ceiling heights, damp-proofing, electricity and water supplies and fire escape routes. If the basement adjoins a next-door property, you may also need to consider an agreement under the Party Wall Act. An experienced London basement company should be able to advise you on what is required for your project and take care of the details for you.

New Basements

Adding a new basement is increasingly popular, especially in densely developed cities where space to add more conventional extensions is at a premium. This is something that requires specialist knowledge in order to dig a new basement beneath the property without damage to the existing structure.

New basements are a relatively new trend, and the rules surrounding them are still evolving so may vary between local authorities. It’s therefore more important than ever to contact your council and find out their view. It’s also worth employing an architect or engaging and experienced London basement company to make sure that the work will be done to the proper standard.

However, many of the areas that we’ve discussed above in relation to conversions will still apply. You will still need to make sure that you comply with the building regulations, and you will have to take account of the effect on any neighbouring properties. Since the work of creating a new basement is likely to be quite disruptive in the short term, it’s always a good idea to make sure that you have your neighbours onside. Again, you will need planning permission if you intend to create a separate self-contained unit.

If your project does require planning permission, remember that this can sometimes take two or three months to grant, so you need to plan ahead and allow some extra time to resolve any issues that may require you to resubmit with changes. It’s well worth employing an expert to ensure that things run smoothly and you get the basement of your dreams rather than the project of your nightmares.