Dormer Loft Conversions – All You Need to Know

A dormer loft conversion is a structural extension which projects vertically from the plane of a sloping roof. By building a dormer onto an existing roof a cramped attic can be transformed into usable space thanks to the creation of additional headroom and floor space all bathed in natural light provided by dormer windows.

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Types of Dormer Loft Conversion

The most popular type of dormer conversion in the UK is a simple flat roof dormer. As well as being the cheapest form of dormer to build, a flat roof dormer also offers the largest amount of additional internal space. A shed dormer also features a flat single planed roof, but sloped downwards at an angle shallower than the main roof. Often used on homes with a gable roof, a shed dormer usually requires different roof sheeting to that of the main roof.

A gable fronted dormer or “dog-house dormer” is a more attractive option which consists of a gable wall extension built up to the existing ridge line, and a new roof section built outwards to the new gable end. Similarly a hipped roof dormer is an aesthetically pleasing option featuring three sloping planes of a hipped roof converging at the ridge of the dormer.

A dormer conversion can often be feasible even in lofts with limited space or headroom

The Pros and Cons of a Dormer Loft Conversion

Dormer loft conversions offer a greater amount of additional floor space than other types of loft conversion. A flat roofed dormer in particular offers the benefits of increased headroom, straight walls and flat ceilings, and is relatively inexpensive to install when compared to a mansard or hip to gable loft conversion. A dormer conversion will provide the top of your property with much needed light and ventilation, and offers a very versatile space suitable for a multitude of uses. A dormer conversion can often be feasible even in lofts with limited space or headroom, and there is a type of dormer suitable for the majority of UK property styles whether typical London Victorian terrace, post war semi or modern detached.

In some people’s eyes a flat roofed dormer might not provide the aesthetic appeal of other forms of loft conversion, but does provide the greatest gain in both floor space and headroom. Whilst a gable fronted dormer or hipped roof dormer can be an attractive addition to a property, it can be more expensive to construct and will not provide as much additional internal space.

Will I Need Planning Permission for a Dormer Loft Conversion?

In the majority of cases, adding a dormer loft conversion to a house falls under permitted development and will not require planning permission. It is however important to be aware of the specific conditions and limitations of permitted development, and if there is any doubt as to whether your proposed conversion passes the permitted development tests we recommend obtaining a Lawful Development Certificate from your local authority. The LDC is not the same as planning permission, but does provide you with written proof that your loft conversion is lawful should questions be raised at a later date when you come to sell your house.

You will require planning permission if:

  • The house is situated on designated land. A roof extension does not fall into the category of permitted development if a property situated within an area of outstanding natural beauty, conservation area, national park or world heritage site.
  • The volume of the new addition exceeds the limits of permitted development. The limits are currently 40 cubic metres for terraced houses, and 50 cubic metres for both detached and semi-detached houses. These limits apply to the size of the ‘Original House’ which refers to the house as it was on 1st July 1948, or if your property was constructed after this date, the size of the house when it was first built.
  • The dormer extension is to be built on the part of the roof that fronts the highway. Any extension beyond the plane of the existing roof slope of the principal elevation may only be constructed on the rear or the hipped side of the roof under permitted development rules.
  • The height of the proposed dormer extension will exceed the height of the existing roof.
  • The materials you plan to use in the construction of your loft conversion are not in keeping with the appearance of the existing house.
  • The dormer loft conversion includes a balcony, veranda or raised platform.
  • The loft conversion includes side facing windows overlooking neighbouring properties. To fall within the conditions of permitted development, any side facing windows must be obscured glass, and only able to open at a height of 1.7 metres above the floor of loft room.
  • The proposed dormer extension reaches less than 20cm from the original eaves when measured along the roof plane.
  • Bats are using the building. As a protected species, a licence is required to carry out work on any building which may disturb or affect the bats’ welfare.

Do Building Regulations Apply to a Dormer Loft Conversion?

Building Regulations Approval is required on any loft conversion on a house, whether or not planning permission is required. Building Regulations are applied to ensure that the structure is completely safe and will cover elements such as structural strength, stability, sound insulation, safety and suitable emergency exits. Abbey Lofts will assist in the approval process throughout your build from the application of the initial building notice to the final inspections.

Dormer Loft Conversion Ideas

Thanks to the usually sizable dimensions of a dormer conversion, your newly created loft space offers endless possibilities. Whether you opt for a spacious master bedroom complete with ensuite bathroom, or a pair of smaller bedrooms linked by a Jack and Jill bathroom, the additional headroom in a dormer enables you to install standard height shower fittings. A dormer conversion can provide a safe, comfortable playroom for the kids, or a stylish contemporary work space benefiting from plentiful natural light. Depending on the size of your property, the space created by a dormer loft conversion can even accommodate a self contained studio flat.

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To discuss your dormer loft conversion ideas and plans, call or email us today