Construction guide

Apartments

Multi-unit housing brings sound, fire and moisture risk between neighbours, plus a body corporate that maintains the building for decades. Here is what changes when you go from a house to an apartment building in New Zealand.

STC 55 / IIC 55G6 design ratings between units; at least STC 50 / IIC 50 measured on site before the CCC [2]

C/AS2Fire Acceptable Solution for buildings where people sleep (non-institutional), including apartments [3]

30-year planLong-term maintenance plan for developments of 10 or more units under the Unit Titles Act [4][5]

What is different from a house

Sound between units (G6)

Walls and floors between units are designed to STC 55 (airborne) and IIC 55 (impact) [1].
Auckland Council expects STC 50 and IIC 50 measured on site before it issues the CCC, so test early and pick floor finishes with acoustic underlay [2].
Services that pass through separating walls and floors need acoustic and fire seals.

Fire (C clauses)

C/AS2 covers buildings people sleep in, including apartments; outside its scope, a fire engineer designs to C/VM2 [3].
Each unit is its own firecell; sprinklers to NZS 4515 or NZS 4541 change what the rest of the design needs [3].
Fire separations, smoke separations and exit signs become specified systems on the compliance schedule.

Weathertightness (E2)

Use the E2 risk matrix early: height, decks, junctions and cladding type all add risk.
Taller or complex buildings often fall outside E2/AS1 and need specific design and a façade or weathertightness specialist.
Drained cavities, clear flashing details and site observation matter more than on a house.

Services

Kitchens and bathrooms in internal units need mechanical extract ducted outside (G4).
Shared risers carry water, drainage, ventilation and power; size them in preliminary design.
Heat recovery ventilation (MVHR) keeps air fresh when windows stay shut for noise or security.

Ownership and the body corporate

Apartments are usually sold as unit titles under the Unit Titles Act 2010; owners share the common property through a body corporate.
Every body corporate keeps a long-term maintenance plan covering at least 10 years [4].
Since the 2024 amendments, developments of 10 or more principal units need a 30-year plan, and the plan drives the long-term maintenance fund and levies [5].
Developers set the plan, budget and building warrant of fitness (BWOF) up before handing over, so design for durable, maintainable materials.

From idea to occupation

FeasibilityCheck the zone (height, coverage, outlook and daylight rules) and any resource consent.
Design teamArchitect plus structural, fire, acoustic, building services and façade consultants.
Building consentFire report, acoustic report, E2 risk assessment, PS1s from each engineer.
ConstructionPre-line acoustic and fire-stopping inspections; on-site sound testing before linings are finished.
CompletionCCC, compliance schedule for specified systems, body corporate set up with its maintenance plan.

Tools for this building type

DuctPlan: ventilation and heat recovery HydroPlan: water and drainage EnergyPlan: H1 and heat loss Electrical plan

Sources

Numbers in square brackets refer to these sources, checked October 2026. Standards and rules change; confirm the current edition with your council and the issuing body before you rely on them.