Designing a Multigenerational Home in Queensland

Multigenerational households are increasing across South East Queensland, driven by housing costs, ageing parents, and adult children staying home longer. A significant proportion of custom build enquiries now involve accommodating more than one generation.

The housing stock was not designed for this. A standard four-bedroom family home assumes one household with one kitchen and one set of living areas, which works poorly when two adult generations share it.

Designing for it properly is not simply adding a bedroom. It is about independence — separate entry, separate living space, acoustic separation and, where permitted, separate facilities.

This is where it gets technical, and it varies by council. Broadly there are three arrangements, and they are treated very differently.

A dual living or secondary dwelling arrangement — a self-contained space with its own kitchen and bathroom, subordinate to the main house — is permitted in many South East Queensland councils subject to conditions. Those conditions commonly limit floor area, restrict whether it can be separately let, and may require it to be occupied by a household member.

A dual occupancy is two independent dwellings and is assessed quite differently, generally requiring development approval and satisfying minimum lot size, frontage, parking and open space requirements.

An extended family arrangement within a single dwelling — additional bedrooms, a second living area, a second bathroom, but no second kitchen — is usually the simplest path, because it remains one dwelling.

The presence of a second kitchen is frequently the line councils draw. Before designing anything, confirm what your specific site and council permit.

The arrangements that work give each generation the ability to live normally without negotiating. The ones that fail put everyone in the same living space with a bedroom door as the only boundary.

Separate external entry is the most valuable single feature. Being able to come and go without walking through someone else's living area changes the relationship entirely.

Separate living space matters nearly as much. Two adult generations watching television together every night is a strain regardless of how well they get on.

Acoustic separation is the item most underestimated. Insulated internal walls, solid-core doors, and separating bedrooms from the other household's living areas prevent the low-level friction that erodes these arrangements. It is inexpensive during construction and impossible afterwards.

Where the arrangement exists to accommodate ageing parents, build for where they are going rather than where they are now.

Single-level access to the secondary accommodation, with no steps between the parking and the entry. Doorways and corridors wide enough for a walker or wheelchair. A bathroom with a level-entry shower, and wall reinforcement behind the tiling so grab rails can be added later without opening the wall.

That last one costs almost nothing at frame stage and saves a genuinely disruptive retrofit later. It is the clearest example of a decision that is trivial during construction and expensive afterwards.

Lever handles rather than knobs, good lighting including at night, and avoiding level changes throughout complete the picture.

Circumstances change. Parents' needs increase, children move out, and the household that the house was designed for may not be the household in it in ten years.

The best multigenerational designs can be reconfigured — the secondary accommodation can become a home office, a teenager's retreat, a guest suite or, where permitted, a rental. That flexibility protects the value of what you built.

It also affects resale. A well-designed dual living arrangement is a genuine selling point to a large and growing part of the market. A poorly integrated one that reads as an awkward extension is not.

We design these regularly across South East Queensland. Our Brisbane custom build page covers how we work through a brief like this, and our secondary dwellings guide covers the planning side.