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Bespoke Living AnnexesAward-Winning Designs15 Year WarrantyOver 18 years’ experience5 Star ReviewsFully Bespoke or Straight to SiteFriendly, Flexible and Capable ServiceComplete turnkey service — Design, Planning, BuildingYour Life, Your Choice, Your HomeSafe, Secure and Trusted
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Annexe project · Cosy Garden Rooms

Cosy garden room with bathroom

5m by 3.5m, built so that a father with dementia has a room he can find his way around — and a bathroom of his own so he need not cross the garden at night.


Published 4 April 2024 · Updated 30 September 2026 · 3 minute read · Written by The Garden Room & Annexe Guide

5m x 3.5m Cosy Garden Room with bathroom
Cosy Garden Rooms  5m x 3.5m, with a bathroom

We often begin our articles by discussing how a garden room can be tailored to the needs of the owner. This recent project by Cosy Garden Rooms perfectly illustrates how these versatile buildings can be designed around you and your family. The clients of Cosy Garden Rooms wanted to create a multifunctional space that could be used as a home office, sitting room, and occasional bedroom.

The need for an occasional bedroom arose for the homeowner’s father, who has dementia and can find navigating the main house confusing. However, the garden room bedroom has proven to be an easier environment for him to manage. Thanks to the addition of a bathroom, the bedroom is self-contained, and with a large section of glazing on the front elevation, it enjoys a lovely connection with the garden.

Inside a Cosy Garden Rooms building with bathroom
Inside

When choosing a garden room for use as a bedroom, even for only occasional use, it is important that it complies with Building Regulations. The Cosy Garden Rooms team can guide you through this process to ensure you are fully compliant.

At a glance

  • Size: 5m x 3.5m, with partition walls making a bathroom out of one end.
  • Who it is for: the homeowner’s father, who has dementia and finds the main house confusing. The garden room has proved easier for him to manage.
  • Why the bathroom matters: it makes the bedroom self-contained, so there is no walk back to the house.
  • The rule that applies: a garden room used for sleeping, even occasionally, must comply with Building Regulations.
  • Foundation: a concrete slab, which Cosy Garden Rooms use on every project for a solid base across the whole footprint.
  • Outside: Hardie® Plank composite cladding in a soft green, Anthracite Grey uPVC frames, and a shallow roof canopy with LED downlights in its underside.
  • Time on site: four days.
  • What it is now: guest room, extra living space and office — the bed swaps out for a settee.

Part of our garden bedroom annexe guide →

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A self-contained annexe
in your garden
No planning permission
required in most cases
Kitchen, bathroom & bedroom
— a home from day one
Fully fitted & insulated,
built in weeks
Based in Brighton & Hove,
building across England
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The building

5m x 3.5m garden room

Following initial design consultations, Cosy Garden Rooms designed a 5m x 3.5m building. Partition walls have been used to create a bathroom. On this occasion, they didn’t fit out the bathroom for their clients, but it is something they can quote for.

Cosy Garden Rooms install a concrete slab foundation on all of their projects, preferring a concrete base over other types of foundation systems as it offers a solid base across the whole footprint of the building.

The multi-layer insulated timber frame structure has been finished with Hardie® Plank cladding in a soft green colour. Hardie® Plank is a maintenance-free composite cladding made from a mix of cement and fibres, creating a highly durable, dimensionally stable board that is not susceptible to rot or fungal attack. Hardie® Plank is coloured during the manufacturing process and does not require painting to maintain its appearance.

Multifunction garden room by Cosy Garden Rooms
Hardie® Plank  in a soft green, with Anthracite Grey frames

The composite cladding has been paired with Anthracite Grey uPVC door and window frames. Anthracite Grey finishes have also been used to detail the shallow roof canopy that runs along the front elevation. LED downlights have been fitted in the underside of the roof canopy, casting an attractive light down the front elevation. This lighting has been fitted with a remote sensor for added convenience.

On site

4-day build

The Cosy Garden Rooms team completed this project in just four days on-site, which is impressive for a building of this size.

Their client is clearly delighted with their new room and the impact it is having on family life:

We love it! It is used as occasional guest accommodation but the bed is swapped out with a settee etc when not being used. Then it becomes an extra living space. And I have also used it as an office so it’s definitely multi purpose!

Planning something similar?

Learn more about Cosy Garden Rooms

To learn more about planning, costs, and what to look for, browse our independent guide to garden rooms.

To learn more about creating a multipurpose garden room, chat with the Cosy Garden Rooms team on 0115 77 22 715 or by emailing info@cosygardenrooms.co.uk. Explore www.cosygardenrooms.co.uk to learn more about their work.

Visit Cosy Garden Rooms More Cosy Garden Rooms projects
More projects like this Garden bedroom annexes Annexes under 25 sqm
Read the guides Garden annexes: the complete guide What an annexe costs The Caravan Act route Granny pods

Published 4 April 2024 · Photographs courtesy of Cosy Garden Rooms.

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A self-contained annexe
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Fully fitted & insulated,
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building across England
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