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Roof additions and alterations to your house

Last updated
20 Nov 2025

Adding a dormer to the top floor of your house can give you extra space. This is an extension, usually with a window, that sticks out of a sloping roof.

This guidance only applies if your home is a dwellinghouse. This means it's a house you live in and is not used for business purposes.

Permitted development

Before you arrange to alter or add to your roof, check to see if you need to apply for planning permission.

Many roof additions or alterations do not need a planning permission application. This is because most meet a set of rules called 'permitted development'.

The permitted development rules are:

  • the dormers are not on the front or side of your house and facing a road
  • the distance between the dormers and the ‘curtilage’ is more than 10 metres - curtilage is the land immediately around your house
  • the development is no higher than the existing roofline - this does not include chimneys
  • all your dormers combined cover less than half the width of the roof
  • the distance between the dormers and any edge of the roof is at least 30 centimetres
  • it is not within a conservation area

Read the Householder permitted development rights guidance on gov.scot to find out more. It includes instances where other restrictions on permitted development apply.

Planning permission

If you want to add to your roof but it is not permitted development, you must apply for planning permission.

Find out how to apply for planning permission. You can also contact your local council for further information.

Planning permission

Always check with your council to confirm if you need planning permission. Even if you meet the permitted development rules, there might be other approvals you'll need to get.

Other approvals

You may need other approvals before starting work. For example, your local council might ask for building regulation approval. 

If you do not own the land, you must get the landowner’s permission (for example, if you’re a tenant or share ownership). 

If your home is a listed building, you’ll also need listed building consent. 

It’s your responsibility to make sure you have all the approvals you need. 

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