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Loft conversion planning permission

Loft conversion planning permission

Loft conversions are a fantastic way to increase the space in a home and also increase a property’s value. There are certain things that you need to bear in mind before you take on a project. If you are planning to convert your loft into a living space, you do not generally need to seek planning permission from your Local Planning Authority. Exceptions apply however to listed buildings and buildings in designated areas. There are also limitations in place if your loft conversion is going to alter your home’s roof space or exceed certain specified limits and conditions.

Loft conversion limitations

Loft conversions are classed as permitted development and therefore, homeowners are free to carry out a loft conversion, subject to the following limits and conditions:

  1. Any new roofing must not exceed an additional 40 cubic metres of space on terraced houses.
  2. Any new roofing must not exceed an additional 50 cubic metres of space on detached and semi-detached houses.
  3. No extension must be made beyond the plane of the existing roof slope.
  4. No extension can be higher than the highest part of the roof.
  5. New roofing materials need to be like-for-like or close to original fittings.
  6. There must be no raised platforms or balconies.
  7. Side-facing windows must be set as such; obscured glaze and opening must be 1.7-metres above floor.

Homeowners should also bear in mind that any previous loft conversions must be included within the volumes and measurements above. If your project is going to exceed any of these limits, you should contact your Local Planning Authority and seek planning permission.

Loft conversions on a listed building

If you plan to carry out internal work on a listed building that will change its character or appearance, you will require listed building consent in most circumstances. Listed building consent is separate to planning permission and governs buildings that have been designated as being of national architectural or historical interest. It is a criminal offence to carry out a loft conversion on a listed property without listed building consent.

For more information on loft conversion, please visit The Planning Portal.


The information contained within this article is strictly for guidance only.  Cost2Build recommends that you always check current sources of information in case regulations have changed. Cost2Build cannot accept any liability for miscommunication of the law in the case of a change in regulation or any action done to a property based on the information held in this article.

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