Do you need planning permission for a garage conversion?

If your home has a garage, which is either underutilised or unused, you may have considered converting your garage into something more practical for you and your family. 

A garage conversion can be a relatively low-cost and quick way of increasing your living space – compared to building an extension – this is because you typically don’t need to lay a new foundation or build walls. Your existing garage may already have power too.

Whether that means adding another bedroom, converting it into a home office or gym or simply adding more practical storage, a garage conversion can not only add much needed space to your home but it can also add value. However, before you get started, it is important to know whether or not you need planning permission for such a project.

Garage conversion planning permission - what you need to know

The planning process can be a long and arduous one. However, there are a number of building projects that can be undertaken with Permitted Development (PD). This means that you don’t need to apply for planning permission to do this work.

But what is covered by PD and what isn’t, when it comes to garage conversions? We spoke to the experts to find out everything you could possibly need to know about converting your garage.

Will the work be internal only?

This is probably the biggest factor when it comes to whether or not garage conversion planning permission is required.

If the work is contained within the garage, you should be able to undertake this work without the need for planning permission.

'In most cases, if the work is internal, uses similar building materials to the existing home and does not enlarge the building, then planning permission is not normally needed,' advises Tabitha Cumming, a property expert from The Lease Extension Company.

Smaller projects such as converting your garage into a utility or storage room, a home gym or even a home office, typically don’t need planning permission. However, there are always exceptions to every rule and there are still some guidelines to follow when building under PD.

When you do need garage conversion planning permission?

In most cases when garage conversion planning permission is required, as long as your conversion is in keeping with the rest of your home and is within your property boundaries, it should be rather straightforward.

But here are some occasions when you will most likely require planning permission:

Change of use

If you plan on converting your garage into a habitable living space, such as an extra bedroom or adding a bathroom to the space, you may require planning permission. 

Another example of when you may be undertaking a change of use is if you plan on converting a garage that is not physically attached to your property.

So, if it is a detached garage, this would not be internal work, even if you don’t plan on adding anything externally to a detached garage. This is because the space is separate from your home.

Increasing the size of the garage

For some, the idea of adding a second story to your garage, in turn doubling the amount of floor space that you have and creating the opportunity to possibly add two new rooms to your property, is a great idea. This sort of change, however, does not fall under PD, so you would need to obtain garage conversion planning permission before starting this work.

To stay within PD, the garage, ‘has to be single-storey with maximum eaves height of 2.5m and maximum overall height of 4m for a pitched roof, 3m for other roofs, or 2.5m if within 2m of the property boundary,’ says Thomas Goodman at Myjobquote.co.uk.

Any additions at all to the outside of the garage will require planning permission.

Adding windows

'Adding windows to the sides or rear of the garage may not always be classed as permitted development,' warns Tabitha from The Lease Extension Company.

One reason for this is to ensure your neighbours’ privacy. Another relates to fire safety.

Not all garages open into an internal hallway. If that is the case with your garage, you may need to install a window or windows to comply with Building Regulations and allow an escape route in case of a fire.

In most cases you can, however, add a window to the front  where a door was present before the works, without needing garage conversion planning permission.

Do I need a lawful development certificate?

Even if you do not require planning permission to convert your garage, it may be wise to obtain a lawful development certificate.

While not a legal requirement, this piece of documentation essentially proves to your local authority and any future buyers – if and when you choose to sell – that your project was constructed legally. It also protects you if planning policies change between when you converted your garage and when you go to sell your home.

For those who would like that added bit of assurance, this could be a worthwhile option.

Still unsure?

If you are at all unsure as to whether you need garage conversion planning permission or not, it is best to contact your relevant local council for advice.

For example, you may need planning permission to make any changes – however small or big – if you live in a conservation area, a national park, an area of outstanding natural beauty or a listed building. This is when you’ll want to get in touch with your local council for guidance.

There are even certain houses, such as those on housing estates, where there may be a clause that prohibits you from using your garage as anything other than a parking space. In most cases this is because there may be a lack of street parking or too many cars parked on the roads in the immediate area. So, in this case, PD would not cover this type of conversion.

‘Even when planning permission isn’t required, it is still crucial that all applicable building regulations are followed, to ensure the structural integrity of the building is maintained, and there are appropriate provisions when it comes to ventilation, fire safety and insulation,’ says Rob Stone, Managing Director of GarageFlex.

Permitted Development

For a definitive guide on what is and what isn’t covered by PD, please consult the Government's Permitted Development Rights for Householders: Technical Guidance. It may be quite the read but it is well worth having a look through. PD also varies ever so slightly depending on where you live in the UK. Find more information for those living in Scotland, Wales and Northern Ireland.