Exploit the space beneath your roof with this guide to planning a loft bathroom.

 Studio 30 architects

As part of a bigger extention, this Victorian terrace dormer conversion includes a main bedroom, by Studio 30 Architects

Adding a bathroom into your loft can be a great use of unused space, but there are important structural and practical issues to consider in the planning stages, to ensure your room is a success. All work will need to comply with Building Regulations, which will also require you to have an extractor fan to remove moisture from the room.

Is there sufficient headroom?

Most roof spaces with a ridge height of at least 2.2m are suitable for conversion. Pre-1960s homes tend to have a steep roof pitch, while more modern trussed roofs may require greater structural changes. Roof windows are an economical solution, but a dormer will increase headroom.

 Chris Dyson Architects

Remodelled and extended 1960s home by Chris Dyson Architects. Bathroom design by Edwina Boase

Raise the roof

Adding a dormer or mansard with a sloping profile and flat roof creates more usable floor space and provides a view of the surroundings. The extra room can also allow flexibility as to where to site the staircase. Those with a hipped roof could consider an upright gable end to create more space.

 Urbanist Architecture

Dormer conversion in a Victorian mid-terrace home by Urbanist Architecture

Making structural alterations

If you need to make complex structural alterations to the roof, this will require the services of a structural engineer, and heavyweight bathroom fixtures and fittings may need the floor joists to be strengthened. Seek advice from a RIBA architect (architecture.com) or try The Institution of Structural Engineers.


Glazed titanium-steel BetteSelect Duo bath, wall-mounted basin and flush-to-floor shower tray, all from Bette.

Making it bright

Having both vertical and overhead glazing will flood the room with natural light. Frameless structural panes or windows with narrow frames will make the space feel bigger, while opaque or switchable glass is an effective privacy solution.


Overhead glazing in a remodelled and extended home by Neil Dusheiko Architects

Water works

Ask a plumber to check if your water supply can cope with the additional capacity and pressure of a bathroom in the loft before getting started. You may need to install a pump to help boost pressure, or alternatively you could fit an electric shower to alleviate demand.

 Architecture for London

Mid-terrace dormer loft conversion with a bathroom beneath a front-pitched roof by Architecture for London

Flooring options

Lightweight, non-porous flooring such as porcelain tiles, engineered timber boards or vinyl is ideal for use in a loft bathroom, especially when fitted on top of underfloor heating.

 CP Hart

Bespoke under-eaves bathroom from CP Hart

Is your loft lacking roof ridge height?

You can create extra head room, says Ana Popovic, architectural and interior designer at Urbanist Architecture

  • Raising or lifting the roof ridge may allow for sufficient headroom of 2m and involves constructing a whole new roof to provide the correct height and pitch. Gable walls will also need to be increased, and these can be built up to match the existing walls or constructed from timber studs and covered in a roofing material. Planning permission will be required and can be difficult to obtain, especially for terraced or semi-detached homes, due to the impact on neighbouring properties.
  • Lowering the loft floor is another option, but you will need to ensure that the floor-to-ceiling height of the floor below isn’t compromised too much – a finished ceiling height of 2.3m is ideal. Period homes are prime candidates due to their generous proportions. How low you can go will also depend on the position of the lower floor window lintels, as you must ensure that structural integrity isn’t compromised. Planning permission is not required, but you will need to consult a structural engineer.
  • Loft pods are prefabricated, modular systems that can be built to any size and shape, and are the quickest way to add extra space. The existing roof is simply altered to accommodate the module. They will require planning permission and Building Control approval, and as the pods are craned into position you should also consider access prior to installation, which is not always feasible. Try Moduloft (moduloft.co.uk).


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