Boarshurst Lofts


Dormer Roof Extensions and Windows

Dormers make up some of our most exciting conversion projects.

Originating from the Latin for sleep, 'dormir', 'dormer' today describes a vertical, windowed roof extension, and they come in many styles.

Types of Dormer

There are many styles and types of dormer, from small windows to large extensions, but the difference in construction is generally one of scale.

  1. Windows: vertical windows set into, and projecting from a gable ( Λ ) roof. The dormer frame spans the width between supporting rafter. They need to be sympathetically designed to form an attractive and stylish addition to the roof, internally and externally.
  2. Extensions: larger, longer roof extensions with vertical sides/cheeks extending to the floor. A structural element such as steel I-beam (RSJ) is used to support the dormer roof section.

Dormer Styles

Design and style often depends on:

  • Where the dormer faces, i.e. to front, side or rear (elevation)
  • The size of loft and room required
  • The existing roof shape, e.g. hip end roofs ( Δ ) gain significant useable area
  • The budget, as costs increases with size

Dormer Designs

The main styles of a dormer to consider are:

Whichever dormer style best suits requirements, when compared with most Velux / ridgeline conversion, major benefits will include:

  • Significantly greater useable floor space
  • Feeling of space
  • Vertical window design options
  • Versatile room use and furniture options

Planning Permission

Do I Need Planning Permission for a Dormer?

The quick answer is a qualified no, they generally come under Permitted Development rights introduced in 2008.

The new rules assume dormers are allowed if within specified limits and conditions. (Our very brief summary, Sept 2012):

Understand the potential within your loft. Book a FREE, no obligation assessment with our professional surveyor.

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  • Generous volume allowances
  • Not to face the front/street
  • No increase in roof height
  • In-keeping with house and street
  • No verandas, balconies or raised platforms
  • Side-facing windows have obscure-glazed
  • Opening 1.7m above the floor
  • Not in designated areas (National Parks, A.N.O.B., Conservation Areas)
  • Set back from the original eaves

See more about dormer plans and planning, and also about our UK wide loft conversion plans services and costs.

The majority of loft conversions, including large dormers do not encounter the expense and delay of Planning Permissions but do need Building Regulation Approval which is cheaper, simpler with less delay to construction.

Building Regulations work off the building plans / drawings, which provide details of the conversion. Building Inspectors inspect and approve the loft as an official additional room(s) to your home, this will not alter the council tax band.

At Boarshurst we have all the skills to expertly assess the suitability of your loft for conversion, and we attend to all Local Authority requirements in our total service. To take advantage of our free, fixed price quotation service and discuss your needs and design ideas contact us today.

Dormer Conversion Plans


The cost of adding a dormer is provided in more detail in our price guide table. As a guide, the cost is approximately £4000 (4 metre wide) to £8000 (8 metre wide) plus vat.

Guaranteed Quality

Our lofts are designed to add value and space to your home and they are guaranteed by us and certified by Building Inspection. We build to current Building Regulation standards and within relevant Planning Restrictions, so you can be sure that your new loft is as safe and sound as it can be.

Contact Us

Contact us to discuss your ideas on 0800 505 3414 and receive a free, no obligation fixed price quote. We convert lofts in Greater Manchester and we provide an Architectural Planning Service throughout the whole of the UK.

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