The National Construction Code (NCC) lets some small boarding houses and guest houses be built to the same housing rules as a home, under the classification Class 1b. That concession only holds while the building stays under two limits, and NSW has other laws that count residents differently.
Two kinds of Class 1b building
The NCC describes two types of Class 1b building:
- A small boarding house, guest house or hostel that would ordinarily accommodate no more than 12 people and has floors totalling 300 m² or less.
- Four or more single dwellings on one allotment used for short-term holiday accommodation, such as cabins. For this type there is no floor area limit, and each dwelling is classified Class 1b whatever its size.
This article deals with the first type, which is the one most owners mean when they say "small boarding house".
How the 300 m² limit is measured
The limit applies to the total area of all floors, measured over the enclosing walls. That means every storey counts, and the measurement takes in the walls themselves, not just the rooms. Shared kitchens, lounges, laundries, hallways and bathrooms count, not only bedrooms. Designs that come close to 300 m² should be measured carefully from the plans early on, because a small extension later could push the building over. If you plan to add rooms in future, check the floor area and head count the building would have afterwards, not just today.
How the 12 person limit works
The test is how many people the building would ordinarily accommodate. That points to its design capacity and normal use, not how many people happen to be there on a given night. Count the beds the building is set up for, and include everyone who lives there. If the room layout could comfortably hold more than 12 people, expect the certifier to ask how occupancy will be controlled.
Over the limits: Class 3
A boarding house that exceeds either limit is generally a Class 3 building. Class 3 brings much heavier requirements, including fire-resisting construction, exit rules and a range of essential safety measures. CertifiBuild certifies Class 1 and Class 10 work only. For Class 3 you need a certifier who holds registration for that class, so we would tell you early if a design goes beyond Class 1b.
Other NSW rules count differently
Being Class 1b under the building code doesn't settle the other legal questions. Two that often catch owners out:
- Registration. Under the Boarding Houses Act 2012, operators of "general" boarding houses (five or more residents, not counting the owner's relatives or a manager) and "assisted" boarding houses must register with NSW Fair Trading.
- Planning. Under the Housing SEPP, a boarding house must provide affordable housing, run by a community housing provider that is registered, in both cases in perpetuity. The NSW Government gives private room sizes from 12 m² for one person up to 16 to 25 m² for a couple. Boarding houses are also no longer a mandatory permitted use in the R2 zone, so your LEP decides.
So a building can be Class 1b, need Fair Trading registration and still face planning limits, all at once.
See our boarding houses page for how we certify Class 1b work. For an existing building, our Building Compliance Assessment reports can show the gaps before you commit. You can also request a quote online.
Local help across NSW
CertifiBuild certifies Class 1 and Class 10 work in 39 council areas. Local rules on these council pages are a good place to start: Hunter’s Hill Council, Lane Cove Council, City of Ryde, Northern Beaches Council, Blacktown City Council, Randwick City Council.
Suburb pages with local planning notes: Huntleys Cove, Linley Point, Macquarie Park, Manly, Marayong, Maroubra, Marrickville, Mascot, Matraville, Mayfield. You can also browse every service area.
Sources
- Building classification rules (NCC 2022 Vol. 2, Part A6), ABCB
- Boarding houses, NSW Government
- Boarding houses and co-living under the Housing SEPP, NSW Planning