Kangaroo housing: two homes, two generations, one building

Why a kangaroo?

The image is the marsupial’s pouch: a small protected home tucked inside a larger one. The older resident keeps a separate household while the family next door keeps a discreet eye out. In return, the elder may collect children from school or receive deliveries.

English speakers may think of a granny flat, a British annexe or an American accessory dwelling unit. The difference is intent: kangaroo housing pairs two unrelated or related households deliberately, with an explicit agreement on mutual support rather than mere proximity.

A Belgian invention

Kangaroo housing developed in Belgium during the 1980s and 1990s, first in Brussels. A frequently cited early example is in Molenbeek-Saint-Jean, linked to the local association Dar Al Amal, which supported families and older residents of the neighbourhood.

In 2019 the Belgian adult-education body CPCP published an analysis of the model, covering its strengths and limits. The Walloon regional housing administration also publishes a review, Les Échos du logement, useful for following regional housing policy.

How Belgium regulates it

In Flanders, a regime called zorgwonen lets owners create a subordinate unit for an older or dependent person through a simple notification rather than a full planning permit. Brussels and Wallonia apply their own planning codes, which can be stricter depending on the works.

The cohabitant-status issue

Belgian social benefits can drop to a lower cohabitant rate when people share an address. Kangaroo projects therefore create two distinct dwellings, with separate letterboxes and two registrations recognised by the municipality, so neither household loses entitlements.

Transposing the idea to France: planning rules

French law has no specific status for kangaroo housing. Ordinary rules apply: creating a second dwelling inside a house changes its layout or use, which often requires a formal step with the town hall before any building work starts.

Purely internal partitioning with no new floor area or exterior change can sometimes go ahead without authorisation. Once a facade is altered, a window opened or an extension built, a prior declaration or a building permit becomes necessary depending on size.

The local plan decides

The municipal land-use plan, the PLU, may require one parking space per new dwelling, cap density or forbid certain splits. Some French towns also require prior authorisation for works that divide a house into several units, to fight substandard subdivided flats.

Taxes and utilities

New floor area can trigger the French development tax, taxe d’aménagement. Two dwellings also mean separate electricity meters, often separate water meters, and distinct letterboxes, so each household is clearly identified at its own address for post and administration.

Which contract between elder and family?

France’s 2018 homesharing contract covers a senior renting part of their own home to someone under thirty; it does not fit two independent dwellings. A standard residential lease is the usual tool, with a separate mutual-help charter setting out expectations.

What does a kangaroo project cost?

Budget depends mainly on works: partition walls, a second kitchen, a shower room, sound insulation between floors and an independent entrance. A house that already has two levels and two doors costs far less to convert than one needing heavy restructuring.

To adapt the older person’s flat, the French grant MaPrimeAdapt’, launched in 2024, covers part of the works for people aged 70 or over, or from 60 with loss of autonomy, subject to income. Rent charged to the family is freely negotiated.

Kangaroo, homesharing or adult foster care?

Three arrangements bring generations under one roof, with clear differences in status and commitment.

Who is it best for?

The model suits an independent older owner of an oversized house who wants to stay put without living alone. It also attracts families on modest incomes in suburban areas, ready to commit to a long-term chosen neighbourly relationship.

Pitfalls to anticipate

Belgian and French experience points to recurring problems.

• Starting works without checking the local plan or filing the right application.
• Skimping on sound insulation between floors, the main source of friction.
• Leaving mutual help unwritten, then discovering mismatched expectations.
• Ignoring inheritance consequences if the house must later be sold.
• Choosing a family on charm alone, without a trial period.

Steps for a kangaroo project

A well-prepared project usually takes between six months and more than a year from idea to move-in.

1. Check technical feasibility with an architect or builder.
2. Read the local plan at the town hall and identify the required permit.
3. Cost the works and look for grants to adapt the elder’s home.
4. Inform heirs and, if needed, a notary about the effect on the estate.
5. Find the family, possibly through a local association.
6. Sign the lease and a mutual-help charter listing services and limits.
7. Review the arrangement after six months.

Frequently asked questions

The answers below concern France unless stated otherwise.

Is a permit always needed to split a house?

Not always. A purely internal split may need no authorisation, but the local plan, municipal rules or exterior works often change that. Visiting the town hall planning department before requesting quotes avoids an expensive retrospective regularisation later.

Is rent from the family taxable?

Yes, as property or furnished-letting income depending on how the flat is equipped. Simplified schemes apply below certain thresholds. A low rent offset by services does not remove the obligation to declare amounts actually received.

Can the family be the elder’s own child?

Yes, and it often is. The set-up is the same, but gift and inheritance rules need care, especially when one child occupies a home rent-free to the possible detriment of siblings.

What happens when the older resident dies?

The family’s lease continues with the heirs as landlords. The elder’s flat can be sold, let or merged back into the other dwelling. Planning this scenario from the outset prevents painful family disputes.