Understanding Weathertightness Issues

New Zealand's weathertightness crisis, commonly known as the "leaky building" problem, has affected thousands of homes and cost billions of dollars in repairs. Understanding these issues is crucial when buying property in NZ.

What is the Leaky Building Crisis?

Between the 1990s and mid-2000s, thousands of New Zealand homes were built with design and construction methods that allowed water to penetrate the building envelope. This wasn't just about poor workmanship—it was a perfect storm of:

• Untreated timber framing (introduced in the 1990s)
• Mediterranean-style designs with minimal eaves
• Monolithic cladding (solid plaster) without adequate cavity systems
• Complex building forms with multiple penetrations
• Inadequate or incorrectly installed flashings
• Insufficient building code oversight during the 1990s-2000s

The High-Risk Period: 1990-2004

Properties built or significantly renovated between 1990 and 2004 are considered highest risk for weathertightness issues. However, problems can occur in buildings from any era if they were:

• Poorly designed or constructed
• Subject to alterations that compromised weathertightness
• Not properly maintained

Warning Signs of Weathertightness Problems

External Warning Signs

• Cracks in cladding particularly around windows and doors
• Staining or discoloration on walls, especially below windows
• Peeling or bubbling paint on exterior surfaces
• Gaps or missing sealant around windows, doors, and penetrations
• Minimal roof overhangs (less than 600mm)
• Complex building shapes with many corners and junctions
• Balconies and decks attached directly to the building

Internal Warning Signs

• Musty smells particularly in bathrooms, laundries, or near windows
• Water stains on ceilings, walls, or around window frames
• Soft or spongy flooring near exterior walls
• Condensation between double-glazing
• Mold or mildew especially in corners or on exterior walls
• Peeling wallpaper or paint near windows and doors

High-Risk Construction Types

1. Monolithic Cladding (Plaster)

Solid plaster cladding systems without adequate drainage cavities are the highest risk. These rely entirely on the cladding being perfectly waterproof—any failure allows water directly into the framing.

2. Mediterranean-Style Homes

Properties with minimal or no roof overhangs leave walls exposed to driving rain. Combined with monolithic cladding, this is a recipe for water ingress.

3. Multi-Unit Buildings

Townhouses and apartments from the leaky building era are particularly problematic because remediation requires agreement and coordination from multiple owners.

The Cost of Remediation

Fixing weathertightness issues is expensive. Typical costs include:

• Full re-clad: $150,000-$300,000+ for a typical home
• Partial repairs: $50,000-$150,000 depending on extent
• Investigation and assessment: $5,000-$15,000
• Structural repairs: Additional $20,000-$100,000 if framing is damaged

What to Do If You're Buying

1. Get a Specialist Weathertightness Assessment

For properties built 1990-2004 or showing warning signs, a standard building report isn't enough. Request a specialist weathertightness assessment that includes:

• Invasive moisture testing
• Thermal imaging
• Detailed cladding inspection
• Assessment of building consent history

2. Check Building Consent Records

Request a LIM (Land Information Memorandum) report and review:

• Original building consents and code compliance certificates
• Any weathertightness assessments or repairs
• Producer statements from designers and builders

3. Ask About Previous Remediation

If the property has been remediated:

• Request detailed documentation of work completed
• Check warranty coverage (typically 10 years)
• Verify code compliance certificates were issued
• Understand what guarantees transfer to new owners

Is a Weathertight Home Ever Safe to Buy?

Yes—if properly assessed and priced. Consider:

• Already remediated: Properties that have been fully re-clad to modern standards can be excellent value
• Price adjusted: If purchase price reflects required remediation costs
• Good bones: The underlying structure and location may still be desirable
• Warranty coverage: Recent remediation with valid warranties provides protection

Insurance Considerations

Properties with weathertightness issues may face:

• Higher insurance premiums
• Limited coverage for weathertightness damage
• Difficulty obtaining insurance if issues are unrepaired
• Full disclosure requirements when applying for coverage

The Legal Landscape

Sellers must disclose known weathertightness issues. If they don't, you may have legal recourse. However:

• Proving sellers "knew" about issues can be difficult
• Legal action is expensive and time-consuming
• A building report is your best protection

Modern Building Standards

Today's building code requires:

• Treated timber framing
• Drainage cavities behind cladding
• Adequate roof overhangs (minimum 600mm recommended)
• Proper flashing systems
• Regular weathertightness testing during construction

Properties built or renovated post-2004 to current standards are significantly lower risk.