Designing a home for several generations: entrances, sound and growing older

Entrances and the path between homes

Start with doors. When each household has its own entrance, a teenager coming home late does not walk past a grandparent's bedroom, and a carer can visit a parent without passing through the main house. Vancouver's multiplex definition already gives each home a direct outside entrance. In a house with a suite, a separate outside door for the suite does the same job.

Then design the path between the homes. A short, covered, step-free path from one door to the other is what makes daily help easy: carrying a meal across, checking on someone at night, sharing the children's pickup. A path with steps, a steep slope or no lighting gets used less, and it becomes a fall risk for an older parent. On a sloped North Shore or Burnaby lot this path can take real design work, because grades at the two doors may differ by a storey.

Door width matters from the first day. Table 9.5.5.1 of the BC Building Code sets 810 mm as the minimum width and 1,980 mm as the minimum height for the required entrance door of a home or a house with a secondary suite. The code's adaptable home article, Sentence 3.8.5.4 (1), asks for a clear width of at least 850 mm with the door open. A family planning for a wheelchair or walker later can use the 850 mm figure as its target from the start.

Sound and fire separation between households

Two generations keep different hours. Sound separation is the design choice that protects both. Article 9.11.1.1 of the BC Building Code asks for STC 43 or ASTC 40 between the homes in a house with a secondary suite, or a listed build with insulation in the joist and stud spaces, a resilient channel on one side and 12.7 mm gypsum board. Between the homes of a duplex or multiplex it asks for STC 50 or ASTC 47. STC is a rating for how well a wall or floor blocks sound, and ASTC also counts sound that travels around it through joined walls and floors. A higher number blocks more.

The code numbers are minimums. A family converting a house to two homes can ask the designer to build the suite separation to the duplex level, STC 50, instead of STC 43. Footstep noise through a floor needs its own design, and our sound separation post covers that. The building code chapter of the multiplex guide covers the full sound and fire rules.

A fire separation is a wall or floor built to slow fire for a stated time. In a house with a secondary suite, Sentence 9.10.9.16 (4) lets the separation between the homes be 15 minutes when all smoke alarms in the house are photo-electric and interconnected, 30 minutes when more photo-electric alarms are added and interconnected, 45 minutes when neither is done, and unrated when the house is sprinklered. Interconnected alarms are wired so one alarm sets off the others. For a household with a grandparent who may sleep through one alarm, that link between homes matters more than the wall rating.

Separate homes in a duplex or multiplex face a stricter rule. Sentence 9.10.9.16 (3) requires a 1 hour fire separation for homes of 2 or more storeys, counting a basement. Other suites need 45 minutes under Sentence (1).

Shared rooms and private rooms

Decide which rooms are shared before design starts, and write it on the plans. The rooms that work well as shared space are the ones nobody needs at the same hour every day: a garden, a storage room, a workshop, a guest room, a large dining room for weekend meals. The rooms that work badly when shared are the ones everyone needs at 7 in the morning: the kitchen, the main bathroom and the front door.

Laundry is the hard case. A shared laundry saves space and one set of machines, and it also means one household walks into the other's space with a basket of clothes. Where the plan allows, two laundry spots remove that daily crossing.

Some families ask for a second kitchen inside one house with no legal suite, so a grandparent can cook separately. Whether a city allows that is a zoning and permit question, so ask the city before it is drawn. The federal tax credit for multigenerational homes also depends on it. The Canada Revenue Agency (CRA) defines a secondary unit for the credit as a self-contained housing unit with a private entrance, kitchen, bathroom and sleeping area. A room with a second stove inside the main home does not meet that definition. The money and tax chapter covers the credit.

Building for a parent who is getting older

Plan the older family member's home for the body they may have in 15 years. That means a bedroom and a full bathroom on the entrance level, a step-free route from the street, and doors and halls wide enough for a walker. A basement suite reached by an outside stair fails most of this. A main-floor home, a ground-level garden suite or the lower home in a stacked duplex with a level entry passes it.

Some of this the code already asks for. Sentence 3.8.5.1 (2) requires houses with a secondary suite, duplexes, triplexes and townhouses, including the suites, to provide at least one bathroom with walls next to the toilet and the shower or bathtub reinforced for grab bars to be added later. Reinforcement means solid backing inside the wall, so a bar can be screwed in later without opening the wall.

The rest is design. Subsection 3.8.5 of the code sets the measures for an adaptable dwelling unit, a home built so it can be changed for a person with a disability later. Even where the rule does not apply, those measures make a practical checklist, shown in the table below. A family can also leave room for a future lift: stack two closets above each other in the same spot on each floor, so a home elevator or platform lift can go in later. The BC home renovation tax credit for seniors names stair lifts, wheelchair lifts and elevators among eligible work.

Heat is the last item. A home for a grandparent should have at least one room that stays cool in summer. The energy-efficient homes guide covers the code's cooling rule for new homes.

Where the adaptable home rule applies

The province's accessibility page (last updated 10 June 2025) says that since 10 March 2025 at least 1 in 5 units must be adaptable in large condominium and apartment buildings and on the first floor of smaller apartments and condominiums. The page says the requirement does not reach units of more than two storeys, units with a separate entry or exit to the outside, and units not reached by an interior accessible corridor. In the code, Sentence 3.8.5.1 (1) applies it to one-storey homes served by an accessible interior public corridor and an accessible common building entrance.

Most family homes on a Metro Vancouver lot fall outside those terms. A house with a suite, a laneway home and a duplex are exempt by Article 3.8.2.1, and a multiplex where each home has its own door to the outside does not meet the corridor test. So the 850 mm doors and turning spaces in the table above are a family's own choice in nearly every multigenerational design.

Vancouver is a separate case. The province's BC Building Code page (publication date 10 March 2025) says BC codes do not apply in the City of Vancouver, which has its own building bylaw. The Vancouver bylaw could not be opened for this guide, so check its accessibility rules with the city for a Vancouver lot.