Home Extension Design

The existing property determines many of the options available.

Rear extensions are a common choice because they can provide direct access to the garden and create additional space alongside an existing kitchen or living room. Side extensions can make use of otherwise underused areas of a plot, while some properties may provide opportunities for a combination of the two.

The size of the extension needs careful consideration.

A larger extension provides more floor space, but bigger is not automatically better. The project also needs to retain sufficient garden space and work with the proportions of the existing house.

Access, neighbouring properties, boundaries, existing drainage and the position of windows also need to be considered.

During the initial survey, South Lakes Windows can assess the available space and discuss how different extension layouts could work with your property.

A new extension should have a clear relationship with the original house.

Internally, this means considering how people will move between the existing and new areas. Externally, it means looking at rooflines, windows, doors, materials and proportions.

Some homeowners want the extension to closely follow the appearance of their existing property. Traditional roof forms, suitable window proportions and complementary frame colours can help achieve this.

Others prefer a more contemporary addition. A flat roof, slim aluminium windows and large sliding doors can create a clear distinction between the original building and the extension.

Neither approach is automatically right for every house. The design needs to respond to the individual property, its surroundings and the homeowner’s preferences.

Natural light is particularly important when extending a house.

Building beyond an existing external wall moves the new windows and doors further away from the original interior. This can reduce daylight in the rooms behind the extension if glazing is not planned carefully.

South Lakes Windows considers the position of windows, glazed doors and roof glazing during the design process.

Large rear windows can provide garden views and daylight. Bi-folding doors, sliding doors and French doors can also introduce significant areas of glass.

Roof glazing provides another source of natural light.

For suitable flat roof extensions, an UltraSKY Flat Skylight can introduce overhead daylight while retaining a low roof profile. An UltraSKY Lantern provides a raised glazed feature that can work particularly well above a dining area or within a larger open-plan room.

The direction the property faces, nearby buildings and trees can all affect the amount of daylight available, so these factors need to be considered for the individual site.

Roof design affects the appearance of the extension as well as its internal character.

A solid insulated roof provides a conventional ceiling and can suit extensions intended to feel like a continuation of the existing house.

South Lakes Windows can use Ultraframe UltraRoof on suitable projects. This lightweight insulated roof system provides a tiled external finish and a solid ceiling internally.

A flat roof can provide a simpler profile, particularly for contemporary extensions. Skylights or lanterns can then be incorporated to introduce overhead daylight.

Another option is LivinROOF, which combines insulated solid sections with selected areas of glazing. This provides greater control over where overhead light enters the extension.

Existing first-floor windows, gutters, eaves and available height can affect the roof designs that are possible. These restrictions need to be identified during the survey rather than after construction has started.

Windows should be positioned around the proposed room layout.

For example, a kitchen extension needs enough solid wall space for units, appliances and storage. Installing glazing across every external wall could make the kitchen itself more difficult to plan.

A home office may require windows positioned to provide daylight without creating excessive glare on computer screens. A dining room could benefit from a larger window positioned to make the most of a garden or countryside view.

South Lakes Windows can supply UPVC, timber and aluminium windows for home extensions.

Aluminium can provide slim frames and larger glazed areas for contemporary projects. Timber can work particularly well with traditional properties, while UPVC provides a wide range of styles and finishes.

Fixed, casement, tilt and turn and other suitable window configurations can be considered according to the room and property.

For many homeowners, improving the connection between the house and garden is a major reason for building an extension.

Door choice therefore forms an important part of home extension design.

Bi-folding doors can create a wide opening by folding multiple panels together. They can work particularly well between a kitchen or dining extension and an adjoining patio.

Sliding doors provide large glazed panels and broad views across the garden. Because the panels move along tracks, they do not require space to swing into the room or garden.

Lift and slide and triple track doors provide further choices for suitable larger openings.

For traditional properties or smaller openings, French doors can provide a straightforward connection with the garden.

The position of the doors is just as important as their style. Access should work with the internal furniture layout and lead naturally towards paths, patios and other outdoor areas.

Home extensions are intended to become permanent living spaces, so thermal performance needs to form part of the design.

Insulation within the roof, walls and floor helps reduce heat transfer through the structure. Modern double or triple glazed windows and doors can also contribute to the overall performance of the extension.

Large areas of glazing require careful planning.

A south-facing extension can receive considerable direct sunlight during warmer periods. The amount and specification of the glass, together with suitable ventilation, can help control internal temperatures.

A north-facing extension receives less direct sunlight, so the balance between glazing and insulated construction may be different.

Rather than selecting the roof, windows and doors independently, we consider how these elements will work together within the finished extension.

Planning requirements need to be considered during the design process.

Some home extensions can be constructed under permitted development rights where the property and proposed work meet the relevant conditions. Other projects require planning permission.

Listed buildings and properties in conservation areas may be subject to additional controls. This is particularly relevant across Cumbria, the Lake District and parts of Lancashire and Yorkshire, where many homes are within historic or protected settings.

Building Regulations can also apply to areas including structural work, insulation, glazing, ventilation and drainage.

Considering these requirements early can help avoid developing a design that later needs significant changes.