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Do I need planning permission for a dormer window?

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Do I need planning permission for a dormer window?

Loft conversions have never been more popular as a lacklustre property market is hardly inspiring homeowners to put up the ‘for sale’ board. Converting unused roof space is a great way to maximize your living accommodation without losing valuable outside areas and garden: you may have already extended to the rear or side of your property and exhausted that particular option.

Speak to a local loft conversion expert to discuss whether you'll need planning permission. Local installers can assess your property for FREE! Fill out the form and speak to local installers near you. 

Unless your house is listed and/or in a conservation area then a loft conversion with simple roofline Velux windows does not usually require planning permission. This is another great attraction of a loft conversion compared to a single or full height extension.

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Dormer loft conversions are the most popular style amongst homeowners because they offer the maximum amount of headroom and floor area. Sometimes they are a necessity because otherwise, the accommodation would be too low or too small but mostly they are the first choice, either to open up an existing roofline loft conversion or as the most attractive option on a new loft conversion project. So, do you need planning permission for dormer windows? The answer to this is, sometimes but not always.

Here are the circumstances where planning permission is not required. These principles do not just apply to dormer windows but to any roof light or alteration to the existing roof structure:-

  • No part of the dormer window is higher than the highest point on the current roof
  • No part of the proposed dormer projects by more than 15 centimetres in front of any existing roof slope on the house which also faces onto a road and would be described as forming the principal or side elevation of the house
  • No part of the dormer is any closer than 0.5 metres to the roof ridge, eaves or any party wall or verge
  • The materials used in any visible exterior work are of a similar appearance to those already on the house
  • Any dormer window on a side elevation that is within fifteen metres of a boundary with another house is glazed with opaque or obscure glazing and is non-opening. The dormer may have an opening feature if those opening parts are more than 1.7 metres above the floor of the room in which the window is situated
  • The house is not listed – if your house is listed then you will need Listed Building Consent
  • The house is not situated in a conservation area

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Why is planning permission not always required?

Every homeowner has the right to alter or develop their property within Permitted Development rights or PD. This is the legal right to make certain changes to a building without the need to apply for planning permission. The law clearly defines what these rights are around your property and not just relating to loft conversions but other works like extensions or physical alterations to the appearance of a building. This is why some dormer loft conversions do not require planning permission whereas others will.

Why are dormer windows so popular?

Dormer loft conversions are the most popular and commonplace choice when it comes to loft conversions and there are lots of reasons for this including:-

  • Dormers add a huge amount of natural light
  • They can increase useable floor area particularly where the pitch to the roof is high and steep and you would otherwise hit your head on the ceiling
  • The room will become a more conventional design just by building a projection upward from the sloping roof
  • Large and modern dormer windows can transform a loft conversion and are considered real features, a statement design which will add more value to your home when it comes to sale time
  • A dormer window can accommodate many more styles of window frame making it easier to match the windows in the rest of the house to keep consistency and uniformity

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What are the different styles and types of dormer windows?

Most dormer windows are not categorised by their style but by how they fit into the overall roof design. There are lots of different dormer window options to suit many styles and types of house.

  • Gable dormer – this dormer is covered with two sloping sides of a roof which meet in the middle and are open in the direction of the window. Gabled houses generally have gabled dormers
  • Shed style dormer – a shed dormer has a roof that slopes in the same direction as the main roof
  • Hipped dormer- for houses with a hipped roof which is a roof which slopes in all four directions of the house. A hipped dormer projects from the roof but also has its own roof sloping down in each available direction. This creates the effect of the dormer looking like its own miniature house which is a feature some people really like
  • Rectilinear dormer – a dormer which projects from the roof as a rectilinear structure and which may have an arched or curved roof which is often called the segmental style
  • Eyebrow dormer – a wavy dormer which protrudes through the slope of the roof and looks like an eyebrow. The window may be fixed and ornamental or operable depending on preference

If you are in any doubt as to whether your proposed project will require planning permission then you should check this out first with your local planning department otherwise you could find yourself in a position where you have to apply retrospectively. If permission is granted then it may not necessarily be to the exact specification of the works you have already constructed or are in the process of building. If permission is not granted then, in theory, you have to put the property back to its former condition before the conversion; with a loft project, this would mean opting for a roofline Velux loft conversion rather than dormers.

Most roofing companies and architects are well aware of which designs fall within PD and which dormer window projects will require planning permission and can advise accordingly.

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