How Big Can a Garden Annexe Be?
Physically, modules can be joined to make an annexe as large as your garden allows; in practice the size is set by the plot, access and what planning will accept. A single P600 gives about 11.4 m² usable floor area.
Adacon Technical Team · Published
Module sizes
P600: 5.9m x 2.2m external, approx. 11.4 m² usable. P400: 3.9m x 2.2m. P300: 2.9m x 2.2m. All are 2.40m high externally with a 2.16m internal ceiling.
Typical annexe layouts
Illustrative only — confirmed in your quotation.
- Compact annexe: one P600 with bedroom/living, kitchenette and shower room
- 1-bed annexe: two joined modules with separate bedroom and living/kitchen
- Larger family annexe: three or more modules forming a proper one-bedroom home
What limits the size
Garden space, distance from boundaries, access for delivery and planning policy. Larger annexes are more likely to need consent.
Worth knowing: Planning, Building Regulations and council tax depend on your site and how the annexe will be used. Confirm with your local planning authority and building control before ordering.