image of The Sycamore Annexe bathroom

Can You Install A Bathroom In A Garden Annexe?

Granny annexes can be defined as a secondary building on your property if it is separate from your main home. High quality granny annexes are mostly self-contained buildings which means they often have everything that is needed. That includes a bedroom, a kitchenette and lounge, and, of course, a bathroom.

For an outbuilding you’re doing up yourself… That’s a different story. But with a bit of planning and some expertise on the subject, it isn’t that big of a deal.

Fitting A Bathroom to a Garden Building

Fitting a shower room, toilet, or even a full bathroom into a garden building can be quite straightforward. And it’s especially beneficial when you plan to use your outbuilding either all day, or every day as an office or studio.

It’s especially essential if you’re considering renting out your outbuilding as a guest stay.

The main elements you need to think about are:

  • Electricity
  • Ventilation
  • Water
  • Plumbing


This is a job for certified electricians – it’s important to maintain safety when working with electricity. Whether you have electrical cables running underground or around the garden can be a personal choice but sometimes it also depends on your garden type and shape and what will work best.

It’s important to think about how you’ll be using your garden building. For instance, using it just for toilet breaks when you’re spending a day in your office is different to running hot water for a heater or a shower. This kind of appliance will require more than 10kW so an adequate power supply is necessary.


Ventilation is vital in any building, but especially in the bathroom of a building. Opening the windows is a good way to ventilate along with extractor fans or humidity sensors.


Water pipes would need to be buried below the frost line, insulated from the cold. This is England, after all! Always at a minimum distance from any electrical cables but running into your building all the same.

Waste pipes can run in the same trench as water supply pipes, though!

Waste / Plumbing

There are factors that may determine the plumbing system and how waste is dealt with. A building located below the level of the existing drains, for instance, would need just a domestic pumping station installed.

But when it comes to an outbuilding or garden outlet, it’s quite a good time to consider any possible alternative options that are available to you. What about recycling rainwater by using it to flush your toilet?

Our Self Containing Garden Annexes

From £61,950, Family Annexe offers a choice of one and two-bedroom annexes.

All of our garden annexes come completed with fully-fitted kitchens as the standard which even includes custom-made units, worktops, doors, sinks, and appliances. There is a standard range for clients and customers to choose from but you also have the option to fully customise your new kitchen to your preferred specification.

Our shower rooms and bathroom suites are nothing short of high-quality with very thought-out and useful options such as soft close toilet seats, low profile shower trays, and towel warmer radiators. If you requirements relating to mobility or accessibility, the bathroom can be amended into a wet room based on the specifications and requirements of the annexe user.

Six annexes to choose from. All self-contained. Built to suit you. Find your new garden home today.

Drop us a line at or call us anytime Monday to Friday from 09:00 – 17:00 on 0330 1332 668 to get in touch with an adviser.