What is a weathertightness assessment?

A weathertightness assessment is a structured inspection of a building's exterior envelope, covering its cladding, windows, doors, roof, gutters, flashings, penetrations and drainage, to identify any areas that may be compromised and allowing water ingress. The assessment is documented in a formal written report that describes the condition of each element, identifies areas of concern and recommends remedial action where required.

When should I commission a weathertightness assessment?

The most common trigger is pre-purchase due diligence on a property where there is any concern about the building's moisture history, construction era, cladding type or building style. Other common reasons include: interior moisture symptoms (staining, mould, damp smells) on a property you already own; planning significant renovations where the condition of the envelope is relevant; or as part of a regular condition monitoring programme for a high-value property.

What is the leaky building problem in New Zealand and how do I know if my home is affected?

New Zealand experienced a widespread weathertightness crisis affecting properties built predominantly between 1992 and 2004. Certain construction styles, including monolithic or direct-fix plaster cladding, low-pitch roofs, complex roof geometry and the use of untreated timber, were particularly susceptible. Moisture ingress through poor detailing created conditions for framing rot that often progressed significantly before becoming apparent. If your property was built in this era and uses these construction methods, a professional assessment is highly advisable.

What does a weathertightness report include?

Our weathertightness reports document the condition of all major exterior building envelope components, including cladding type and condition, flashings, window and door seals and surrounds, roof condition, gutter condition and drainage, penetrations (pipes, vents, cables), and ground clearances. Where moisture testing instruments are used, readings are recorded. The report provides a summary of condition, identifies areas of concern in order of priority, and recommends specific remedial actions.

Is this the same as a LIM report or a building inspection?

No. A LIM (Land Information Memorandum) is a council document about the property and any consents, notices or conditions on its title. A standard building inspection covers the broader condition of the building. A weathertightness assessment is specifically focused on the building envelope and its ability to exclude water. For a property where weathertightness is a genuine concern, a specialist assessment provides significantly more detailed information than a general building inspection.

Do you carry out moisture testing as part of the assessment?

Yes. Where indicated by visual observation, we use moisture testing instruments to take readings through the cladding to assess whether elevated moisture levels are present in the substrate. These readings are documented in the report. Moisture testing is particularly important for direct-fix plaster properties and monolithic cladding systems where moisture ingress can be concealed behind an intact exterior surface.

Assessment & Reporting · Auckland

Weathertightness Assessments & Reports

For high-value properties, uncertainty about weathertightness is not a position you want to be in, whether you're buying, selling or simply ensuring your existing asset is in the condition you think it is. A professional weathertightness assessment provides a clear, documented picture of your building envelope.

Prevent Maintenance provides professional weathertightness assessments and formal written reports for residential and commercial properties across Auckland. Our assessments cover the full building envelope: cladding, windows, doors, roof, gutters, flashings and drainage, with moisture testing where indicated. Reports are delivered in a clear, professional format suitable for property transactions, insurance purposes and asset management records. We are trusted by owners of high-value homes, real estate professionals and property managers who need credible, thorough weathertightness reporting.

The New Zealand Context

Why weathertightness matters in Auckland

New Zealand experienced one of the worst housing weathertightness crises of any developed country. Properties built from the early 1990s through to the mid-2000s during a period when building regulations, materials and construction practices created a perfect set of conditions for moisture ingress and framing failure, affected tens of thousands of homes.

Auckland, as the country's largest city, has the highest concentration of affected properties. Many remain unidentified, particularly where superficial remediation or cosmetic work has been carried out without addressing the underlying moisture issues.

Beyond the legacy crisis, weathertightness is an ongoing concern for any property in Auckland's wet, humid climate. Building envelope deterioration is continuous: sealant fails, flashings lift, cladding systems develop gaps, and the consequences of missed moisture ingress on a high-value property can be severe.

High-Risk Construction Characteristics

If your property has any of these characteristics, a weathertightness assessment is strongly advisable before purchase and recommended periodically as an owner:

Built between approximately 1992 and 2004
Monolithic plaster or EIFS cladding (direct-fix or face-fixed)
Complex roof geometry: parapet walls, internal gutters, multiple valleys
Low roof pitch (under 10–12 degrees)
Untreated timber framing (common pre-2004)
Multiple levels with varied cladding transitions
Penetrations without properly formed flashings
Balconies or decks over habitable space

What's Assessed

A complete building envelope assessment

Cladding Systems

Full inspection of cladding type, condition, fixings, joints, ground clearances, and any visible areas of deterioration, cracking or previous repair.

Windows & Doors

Sealant condition, flashings, head and sill detail, frame condition and any visible moisture staining, rot or seal failure.

Roof & Flashings

Roof material condition, flashing integrity, penetration details, ridge capping, valley condition and water egress pathways.

Gutters & Drainage

Gutter condition and function, downpipe outlets, drainage at ground level and any evidence of persistent overflow or pooling.

Penetrations

All pipe, vent and cable penetrations through the cladding: flash detail, seal condition and evidence of water ingress at each location.

Moisture Testing

Where indicated by visual observation, capacitance moisture meter readings are taken through cladding and documented with locations and readings.

Who This Is For

When a weathertightness assessment is the right step

Weathertightness assessments are most commonly commissioned in the context of property transactions, either as part of a purchaser's due diligence, or by a vendor who wants to provide prospective buyers with documented confidence in their property's condition.

They are also valuable for existing property owners who want a baseline condition record, who are noticing symptoms that may indicate moisture ingress, or who are planning to make a weathertightness insurance claim or dispute.

Pre-Purchase

Commissioning a weathertightness assessment before purchasing a property built in the risk era, or any property where the construction or condition raises questions, is straightforward due diligence for a significant asset purchase.

Pre-Sale

Vendors of premium properties increasingly commission assessments to provide buyers with transparent documentation and reduce negotiating uncertainty.

Existing Ownership

If you are noticing interior moisture symptoms, staining, mould or musty odours, or if your property has not been formally assessed and you have any doubt, an assessment provides clarity.

Portfolio Management

Property managers and investors with multiple properties use periodic assessments as part of a structured asset management and maintenance programme.

The Prevent Standard

How our assessments work

Our weathertightness assessments are thorough, systematic and fully documented. The report is written to be useful. Not opaque, not hedged into meaninglessness, but clear about what was observed, what it means and what action is recommended.

We are direct in our reporting. If a property has weathertightness concerns, we document them clearly and explain the implications. If the envelope is in sound condition, we say so with the same clarity.

Engagement & Briefing

We discuss your specific context, whether it's pre-purchase, existing ownership or another purpose, and confirm the scope and timing of the assessment.

On-Site Inspection

A structured inspection of the full building envelope is carried out by an experienced assessor, including visual inspection and moisture testing where indicated.

Documentation

All observations are recorded on-site, including photographic documentation of each element assessed and any areas of concern.

Report Preparation

A formal written report is prepared covering all assessed elements, moisture test results, condition summary, identified concerns and prioritised recommendations.

Report Delivery & Discussion

The completed report is delivered electronically. We are available to discuss the findings and answer questions arising from the report.

Pricing

Fixed-fee assessment pricing

Weathertightness assessments are priced based on property size, complexity and travel. All assessments include the on-site inspection and a formal written report. Pricing is confirmed before engagement.

Assessment & report from

$[X]

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Includes on-site inspection, moisture testing where indicated, and formal written report. Pricing confirmed before engagement based on property specifics.

Frequently Asked

Weathertightness assessment questions answered

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Commission a professional weathertightness assessment

Whether you're buying, selling or protecting what you own, a weathertightness assessment provides the documented clarity that high-value property decisions deserve.

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