Pre-1940s: Villa & Early Bungalow Era
Common features
- Timber weatherboards, corrugated iron roofs, high ceilings, timber piles
Key risks
- Subfloor decay or rot, rubble foundations beneath original timber piles or framing
- Poor insulation or none at all
- Outdated wiring and plumbing, such as cloth-covered wires and galvanised pipes
- Lead-based paint and asbestos
- Borer and fungal decay in untreated native timbers
Recommended checks
- Subfloor inspection
- Electrical rewiring status
- Insulation upgrade feasibility
- Lead and asbestos testing
1940s to 1960s
Common features
- Simple, durable timber construction, concrete tile or iron roofs
Key risks
- Asbestos in cladding, roofing, vinyl flooring, and soffits
- Original wiring and plumbing may still be present
- Poor insulation, especially underfloor and within walls
- Single-glazed windows and low thermal efficiency
- In-ground waterproofing issues
Recommended checks
- Asbestos survey, especially before renovations
- Retrofitting insulation
- Status of rewiring and plumbing
- Roof condition, as older concrete tiles may become brittle
1970s to 1980s: Fibrolite & Hardboard Era
Common features
- Low-pitched roofs, monolithic claddings, aluminium joinery
Key risks
- Hardboard claddings such as Weatherside, prone to swelling and rot
- Leaky plumbing, Dux Quest pipes especially in the 1980s
- Flat roof designs prone to water ponding or leaks
- Minimal insulation
- Asbestos still found in some eaves, ceilings, and linings
- In-ground waterproofing challenges
Recommended checks
- Cladding moisture testing
- Roof design and drainage efficiency
- Plumbing material verification, as Dux Quest is a major concern
- Asbestos check
1990s to mid-2000s: Leaky Homes Era
Common features
- Direct-fixed plaster (monolithic) claddings, complex rooflines, little or no eaves, aluminium joinery
Key risks
- Leaky building syndrome, especially with monolithic cladding such as Harditex, Sto and Rockcote
- No cavity system
- Poor junctions between roof and wall, missing flashings
- Inadequate waterproofing at balconies and decks
- Hidden rot and moisture damage
- Insurance complications due to stigma and known issues
- Expired weathertightness claim eligibility
- In-ground waterproofing deficiencies
Recommended checks
- Full weathertightness building report
- Invasive moisture testing around windows, decks and parapets
- Verification of any recladding or remediation work
Mid-2000s to 2012: Transition to Better Code Compliance
Common features
- Return to weatherboard-style construction, cavity systems introduced
Key risks
- Residual leaky design features in some homes, especially plaster-clad townhouses
- Ongoing risk in buildings with flat roofs or parapets
- Lack of maintenance on exterior sealants and flashings
- Questionable workmanship during the building boom of 2004 to 2008
- In-ground waterproofing concerns
Recommended checks
- Confirmation of code-compliant cavity systems
- Moisture scanning in plaster-clad areas
- Roof and cladding detail review
- Review of Code Compliance Certificates and building consents
Post-2012 to present: Modern Code-Compliant Builds
Common features
- Mandatory cavity systems, modern insulation, double glazing, improved flashings
Key risks
- Build quality varies, especially in high-volume housing developments
- Low-slope roofs and internal gutters require proper maintenance
- Airtight homes may have poor ventilation, leading to condensation or mould
Recommended checks
- Roof pitch and internal gutter design
- Adequate mechanical ventilation systems
- Evidence of quality control during construction
- Review Code Compliance Certificates, warranties, and maintenance history
Cross-era risks to watch for
- Asbestos, common in homes built before 2000
- Dux Quest plumbing, 1980s to early 1990s
- Leaky building designs, late 1980s to 2004
- Flat or low-pitch roofs, all eras
- Deferred maintenance, which can conceal serious defects
- Non-consented renovations, with legal and safety implications
- New Zealand house construction risks
- NZ property age risks
- property inspection checklist NZ
