Extending upwards can be the most cost-effective way to increase the size of your home. Provided the existing foundations can support the load of an additional storey (which will generally be of relatively lightweight construction), the process is quite straightforward, and most of the work can often be done with minimal disturbance to the rest of the house.
Quite a lot can be achieved at roof level under permitted development rights, meaning a full planning application may not be necessary, but always check with your local authority, especially if your property is in a conservation area or is listed. The Government’s online Planning Portal contains a lot of useful information about permitted development and planning matters.
Be mindful that daylight and views are typically at their best at the top of the house, so be sure to exploit both wherever possible when planning a roof extension. The design of stairs and spaces with sloping roofs requires particularly careful study, so don’t try to figure it out as it’s being built – engage the services of a design professional to exploit your extension’s potential to the fullest.
Showcase the stairs
If you’re converting your loft, you’ll need a new staircase, so make it an object of beauty you’ll appreciate every time you use it. This winding version, although tucked into a corner, subtly draws attention to itself through its clean and crisp detailing.
Pack plenty into the space
Maximise the return on your investment by making every square metre work as hard as possible. In this bedroom roof extension, the spaces below and beside the picture window incorporate a window seat, storage drawers for shoes, and floor-to-ceiling shelving.
Turn unusual angles into a feature
Rather than fighting the sometimes quirky geometry roof shapes can impose on a space, celebrate them. Here, the apex of the roof conceals accent lighting that draws the eye upwards, and the gable wall makes a perfect backdrop for the bed.
Absorb awkward shapes
A successful design should eliminate any awkward ‘leftover’ spaces. Use low, under-eaves areas for storage and disguise structural elements, such as plumbing, by building out in front of them to create useful areas, such as this bedhead ledge for those night-time essentials.
Think transparent in tight spaces
Judicious use of glass can help to make small spaces look and feel larger, as well as bringing in lots of light. The frameless glass roof over the stairs to this roof extension folds down the back wall to become a window, blurring the boundary between inside and outside. The bathroom is separated from the stairs with a frameless glass partition to take advantage of the light from the roof.
Enjoy the great outdoors
This small, glazed extension provides access to a roof terrace and brings light down to the floor below. Being largely transparent, it doesn’t spoil the panorama from elsewhere on the roof, and the seat placed at the top of the stairs allows the terrace to be enjoyed from inside even when it’s raining.
Incorporate a balcony
This roof extension to a period house cleverly incorporates a small balcony space by setting the exterior wall of the extension slightly back from the existing wall below. Note, too, how the roof overhangs to provide shade and some protection from the rain.
Frame a view
In a multi-storey house, a lot of time is spent walking up and down the stairs. So make the most of time spent there by capturing a view to enhance the experience. In this case, the L-shaped window frames a view from the top of the stairs as well as from halfway down.
Build ceiling height into a bathroom design
Many roof extensions incorporate bathrooms or shower rooms. If the ceiling is not level throughout, as is often the case, plan out where sanitary fittings will go based on how much headroom will be needed for each item. Here, the showering area is under the higher section of the sloped ceiling, with a built-in bench and feature niche occupying the space where height is restricted.
Consider the exterior
This Edwardian terraced house in a London conservation area has been extended on both the main roof and the rear outrigger (the grey area). The dormer windows are appropriate to the historic character of the house, but the cladding is zinc, which gives the roofs a more contemporary appearance.
Give yourself a window on the world
Sliding or folding glazing doesn’t just belong at ground level – it can add drama and help create that inside-outside feeling even in a lofty bedroom.