Garden Annexe Design and Layout

Start with siting, not the floor plan

Where the annexe sits in the garden decides a lot of the design. Foul drainage is usually the deciding factor: the kitchen and bathroom need to reach the existing drains at a workable fall, or a pumped system is needed. The planning and regulations side is covered in the main garden annexe guide.

Next is the relationship with the house. A clear, lit path from the back door matters for an older relative, and a window facing the house helps everyone feel connected without living on top of each other. Privacy for neighbours, trees and root zones, and access for building materials also shape the position.

A typical one-bedroom layout

Most annexes follow a simple pattern that keeps plumbing short and rooms well proportioned.

Entrance into the living and kitchen space, not directly into the bedroom · Kitchen run on the wall shared with the bathroom, so waste pipes are short · Bathroom between the kitchen and bedroom, acting as a sound buffer · Bedroom at the far end, with its own window and space for a wardrobe · Living area facing the garden and the house, with the largest glazing

Designing for an older relative

Many annexes are built so a parent can live close by while keeping their independence. Designing accessibly from day one is much cheaper than adapting later.

Level threshold at the door, doorways wide enough for a walking frame or wheelchair, a level-access shower with space to turn, lever taps and handles, sockets at a comfortable height and good lighting throughout all make a real difference. The accessible adaptations guide lists further details that apply equally to an annexe.

Light, heat and comfort

Because someone sleeps and cooks in there, comfort standards are those of a home rather than a garden room. Good insulation, controllable heating and hot water, and ventilation that deals with steam from cooking and showering are essential. Rooflights brighten the middle of a deeper plan, and blinds or overhangs on south-facing glass stop the living area overheating.

Storage is always underestimated

Someone moving into an annexe often brings a lifetime of belongings into a much smaller space. Built-in wardrobes, a utility cupboard for a washing machine and the boiler or cylinder, and storage under window seats or beds make the difference between a calm home and a cluttered one. A small separate store outside keeps garden tools and mobility aids out of the living space.

Room sizes and proportions

No annexe sizes or prices are published on this site, because the right size depends on the garden, planning and who will live there. As a rule of thumb, the bedroom should fit a bed with space to walk around it and a wardrobe, the shower room should allow a carer to assist if needed, and the living area should have room for a small dining table as well as seating.

Frequently asked questions

What is the best layout for a garden annexe?

Entrance into the living and kitchen area, bathroom between the kitchen and bedroom, and the bedroom at the far end, with plumbing kept to one side near the drains.

How do you design a garden annexe for an elderly parent?

Level access, wide doorways, a level-access shower, lever handles, good lighting and a lit path to the main house, all designed in from the start.

Where should a garden annexe go in the garden?

Usually where the kitchen and bathroom can reach the existing drains, with a clear path to the house and consideration for neighbours and trees.

Does a garden annexe need planning permission?

In almost all cases, yes, because sleeping accommodation is not incidental to the house. The main garden annexe guide explains why.