Under one roof: multi-generational living
With multi-generational living being promoted as one potential solution to the island’s housing issues, Rachel Jones, senior associate in Carey Olsen's property team, sets out what islanders need to consider when creating additional accommodation in their properties.
An original version of this article was first published in Issue 19 of Guernsey Property and Construction magazine, May 2026.
It is well known that Guernsey is facing significant housing pressures, with the shortage of houses and housing affordability being long-term issues.
The Development & Planning Authority has recently published a statement encouraging multi-generational living by altering existing homes to create additional affordable accommodation.
Multi-generational living allows two or more adult generations in one family to live in the same home with privacy. For example, adult children (and maybe their children) living with their parents, or elderly parents living with their children (and maybe grandchildren). Multi-generational living enables families to share financial responsibilities, household chores, and support each other in many ways, including with care and childcare.
Multi-generational living is achieved by creating ancillary or associated living accommodation that is attached to or situated within the curtilage of a dwelling. Such accommodation is often known as a "dower unit" and may be self-contained but cannot be occupied as a separate dwelling independent from the main dwelling. This may be achieved by converting a garage or an outbuilding, creating an extension to the dwelling, or by erecting an outbuilding. In all these cases, the garage/outbuilding must be within the domestic curtilage of the dwelling.
Some may be surprised to learn that planning permission is not always required to create such accommodation, provided that the dwelling is not sub-divided and certain exemption criteria are satisfied. For example, for the erection of an extension to the dwelling, the criteria includes that no part of the extension can be closer to the highway than the existing house, the internal floor area of the extension must be no more than 30 square metres, and the dwelling cannot be a protected building or monument or be within an area of special significance.
If planning permission is not needed, building control approval may still be required. It is also important to consider whether planning permission may be required for certain alterations, such as changing a garage door to a window. Previous planning permissions for the dwelling should also be checked to ensure there are no relevant planning conditions that restrict the use, for example, a condition requiring a garage to be retained for vehicle parking (in which case planning permission would be required).
If planning permission is required to create the proposed ancillary or associated living accommodation, the proposals would be assessed against the relevant planning policies in the current Island Development Plan, which generally support proposals for ancillary or associated living accommodation subject to certain criteria.
Whilst multi-generational living can provide much needed housing accommodation for family members by the creation of ancillary or associated living accommodation, some may argue that the policies should allow such accommodation to be used or occupied as a separate dwelling, independent from the main dwelling, to provide further housing. This may be something to be considered in the future to achieve the delivery of much needed housing.
