Dormer extensions and loft conversions

Dormers can be a cost-efficient way of adding extra space to your home, often as part of a proposed loft conversion. 

However, poorly designed, poorly sited, or large-scale dormers can detract from the established character of an area, especially if located on the front of a property where such features are not already a common feature in the area.   

Rear dormers - permitted development rights

You often don’t need planning permission for dormers on the rear roof slopes of your house. That’s because of the provisions made by government regulations commonly referred to as ‘permitted development rights’ (or PD rights).  Further information regarding these regulations can be found on the Planning Portal website:

However, it is important to note that this does not apply to dormers on the front roof slope of a property.   

If you want to use these rights to erect a rear dormer it is your responsibility to make sure it complies with the regulations as, if it doesn’t, you could be at risk of having action taken against you because it means it could be an unauthorised development.  

We can help

You can get advice from us about whether you need planning permission for your dormer in one of two ways: 

  1. Use our pre-application advice service for a “Permitted Development enquiry”.  A planning officer will respond in writing with an informal opinion about whether the proposals comply with the requirements of the permitted development regulations

  2. Submitting an application for what is known as a ‘Certificate of Lawfulness for a Proposed Use or Development’.  This is a formal application where we will issue a decision confirming whether the proposals comply with the requirements of the permitted development regulations.  Such applications can be made via the Planning Portal website. 

Using one of the above options will provide homeowners with some comfort that their development can be carried out without planning permission.  It can also prove helpful when the time comes to sell their property in the future, since a buyer’s conveyancing solicitors may require evidence that development to the property either has planning permission or some evidence that demonstrates that it was not required.   

Front and side dormers

Front and side-facing dormers always require planning permission.  Therefore, a planning application must be made for these before any development takes place.  When submitted, we will assess the proposal against our adopted policies.  These policies are primarily focused on ensuring that such dormer extensions are designed appropriately, are compatible with the existing house, would integrate with the established character of the existing area, and would not cause loss of amenity to the occupiers of adjacent or adjoining properties.   

Guiding principles

The guiding principles set out below are aimed to help applicants and their architects design dormers which integrate sympathetically with their property and which is compatible with the surrounding area: 

  1. Dormers should sit well within the roof slope, and be set an appreciable distance away from gables, hips and eaves. 
  2. Dormers should ordinarily be set back a minimum of one metre from the front wall. 
  3. Dormers should be set below the ridge of the roof so that the roofline is unaltered. 
  4. Usually, dormers should be situated on the roof of the original dwelling, not earlier extensions. 
  5. Dormer windows should be aligned with and match the front elevation of the property and its existing windows. 
  6. New windows should not overlook habitable room windows in neighbouring properties and, where possible, should avoid overlooking of the private open space of neighbouring properties. 
  7. Flat roof front dormers should be avoided except in instances where they are an existing characteristic of the street scene. 
  8. Materials should match or complement the existing roofing material. 
  9. Avoid dormers which wrap around the ridge of a hipped roof. 

Conservation areas and listed buildings

If your property is in a conservation area, it is important that your proposals are in-keeping with the area’s established historic character.  Where dormers are proposed, their design and materials must also be architecturally and historically accurate and reflect the character of the building and wider area.  Ordinarily, this would involve a traditional appearance, with a hipped or gabled roof. 

If your property is a Listed Building, in addition to the possibility of needing planning permission, you will also need to submit an application for Listed Building Consent.   

Examples of well and poorly designed dormers

The images below show examples of dormers that are more likely to be considered acceptable, along with those which are not: 

Acceptable examples:

Example of a well designed dormer extension

 

Example of a well designed dormer extension

 

Unacceptable examples:

Example of a poorly designed dormer extension

 

 This dormer dominates the hipped roof of the property and appears disjointed and large.
Example of a poorly designed dormer extension This dormer dominates the roof of the property and appears completely out of character to the terraced row of which it forms part of.  Its height also exceeds the height of the roof ridge of the house.
Example of a poorly designed dormer extension

 

 This dormer is very close to the eaves, dominates the roof, and has windows which have no resemblance to the size and position of windows in the main house.

Building regulations

In almost all circumstances you will need to satisfy the Building Regulations.

This is to ensure amongst other things that your home remains: structurally safe, the emergency escape provisions are appropriate; the property is energy efficient and has adequate ventilation.

This applies whether you are proposing to live in the additional space that you create or not. The requirements may be different if you only propose to construct a rudimentary storage area in the loft.

You can get further advice on this from the Building Control Team.

It is a criminal offence not to comply with the Building Regulations. Furthermore, undertaking works in contravention could complicate or jeopardise any future property sale, as conveyancing solicitors are obliged to ask for copies of all approvals /completion certificates before concluding a sale.

Apply

Please contact the Building Control team for a copy of the application form you require:

Fees

For some Full Plans applications, part of the fee is payable upon submission of the application, and the other part is invoiced for, after the first inspection by Building Control officers. This is dependent on the work category and is shown within the charges information.

For a Building Notice application, a fee is payable upon submission of the application.

Storing light materials in lofts

Up to 50% of the floor area of the roof space may be loosely boarded to store light items such as suitcases and Christmas decorations before requiring Building Regulation approval.

Ceiling joists are only intended to act as a fixing for the ceiling below and are not designed for heavy loads. It is important to prevent overloading ceiling joists.