Talk to one of our experts:
0117 9478200 /

Does Your Conversion or Extension Need Planning Permission?

Posted by Hermione
4th August 2017

Architecture blueprint with pen and ruler

If you seek to make major construction changes to your property, planning permission is almost certainly required. Even minor alterations may fall foul of the law if they don’t satisfy current building regulations.

Completing work without obtaining the relevant permission – as many UK homeowners do according to a study by the Co-Op –  can see you served an ‘enforcement notice’. This means you’ll have to undo all the changes made, usually at great expense and hassle.

It’s therefore highly recommended to ask a building and conversion specialist before undertaking a conversion or extension, no matter how inconspicuous it may seem.

Loft Conversions

A loft conversion is mostly deemed as a permitted development as you’re not altering the building specifications. However, for projects involving an extension of the roof space or damage to the party wall, planning permission will be required.

Other conditions that may breach a permitted development include:

  • An increase of 40 cubic metres in volume for terraced properties, or 50 cubic metres in volume for detached and semi-detached properties
  • An extension that increases the highest part of the roof
  • An extension that increases the angle of the principal elevation
  • A clear change in materials from the existing building
  • Extensions in designated areas, i.e. areas of outstanding natural beauty.

Garage Conversions

Again, a garage conversion usually doesn’t require planning permission if the work is a simple renovation of the existing room. However, some conversions involve changing the face of the property which is where local authority approval must be sought.

You’ll also need to obtain a ‘change of use’ agreement as the garage is transforming into a habitable space – this is especially the case for standalone, detached garages.

Care needs to be made in regard to insulation, ventilation, electrical supply, heating and fireproofing, etc, before one is issued. A conversion specialist will take care of this on your behalf.


It is almost certain you’ll need planning permission for an extension as the property is being lengthened. This will definitely be the case if the extension:

  • Increases the height of the property, or is higher than four metres
  • Is wider than half the width of the existing dwelling
  • Involves new materials that don’t match the existing building aesthetic
  • Will take up more than 50% of your private garden area
  • Includes balconies, verandas or raised platforms.

There are many more specific building regulations to adhere to, although much depends on the size and shape of your home, as well as the type of extension required. It’s therefore vital that professional advice is undertaken before any work begins.

Further Information

Although you can apply for planning permission online, we strongly recommend using a building specialist such as MPK Lofts to oversee the process.

Having completed numerous projects down the years, we’ve come across all sorts of properties and can advise whether your home needs planning approval or not. We’ve built up a great relationship with local authorities and can use these connections to assist with your planning permission.

For any more information please feel free to get in touch today.


If you’re wondering how to pay for your extension or conversion, then remortgaging might be the answer. Take a look at how remortgaging can pay for your home improvements and save you money.

Posted by Hermione
4th August 2017
MPK Lofts
90 High Street, Hanham Bristol, BS15 3EJ
0117 9478200