Weathertightness Reports Explained: What's in One, What It Costs and How to Read It

Someone hands you a weathertightness report: photos, colour-coded moisture maps, a risk rating and a page of recommendations. That document usually decides whether a house gets a small repair, a partial reclad or the full job, so it pays to know what you're reading.

What a weathertightness report is, and what it isn't

It's a written assessment of how well the outside walls keep water out, and whether any has already got in. The Ministry of Business, Innovation and Employment (MBIE) says reports like this are read by homeowners, by the people designing a repair and by building consent officials. So a good one is written to be used, not filed.

It isn't a standard building inspection. A standard inspection covers the whole house, roof to plumbing, while a weathertightness report looks closely at the walls, the windows and the places where one material meets another. It also isn't a guarantee. It describes the house as it was on the days it was inspected.

What's inside one

MBIE's guide to the diagnosis of leaky buildings sets out what a full report should cover. In plain English, these are the parts.

• The brief and summary. Why the report was asked for, and a short summary of what it found.
• The house's background. Its age, how it was built, and its repair history.
• How the checks were done. The dates, the weather on each day, and the methods and equipment used.
• What was found. Maps, drawings and photos showing where moisture readings were taken and where the walls were opened up.
• What it means. Where water is getting in, how far the damage has spread, how likely the wall is to keep leaking, and a risk rating for the design of the house.
• The recommended repair. What should be done, why, and a rough estimate of what it will cost.
• Supporting documents. Plans, manufacturer information, earlier reports and anything else the findings rest on.

Some people only need a short report. A report that will be used for a legal claim has to carry more detail. Whatever the length, the same parts should be there.

How to read one

You don't need to read every page. Four things tell you most of what matters.

1. The summary and conclusions. Read these first. They tell you what was found and what is recommended.
2. The moisture maps. A high reading marks a spot that needs a closer look. It doesn't confirm rot. MBIE's guide says meter readings are indicative only, and recent weather can affect them. A low reading doesn't prove the wall is dry, either.
3. What wasn't checked. A report only covers the walls that could be reached and the tests that were done. If an area was left out, or nothing was opened up, the report should say so, and that gap matters.
4. The risk rating. Some reports score the design of the house for risk. Auckland Council's reclad guide uses a score like this to flag the more complex jobs, and strongly advises an early meeting with the Council for those jobs. Our guide to the Building Code's E2 clause covers the rules behind the score.

Leave the repair estimate till last. It's only an estimate: prices firm up once the repair is designed and quoted.

When you need one

Not every house needs a report. These are the situations where one is worth the cost.

• You're buying a house built in the high-risk years. Homes built from the late 1980s to the mid 2000s with plaster-style (monolithic) cladding carry the most risk. The government's buyer guide, Learning about leaky buildings, recommends an independent inspection by someone who specialises in weathertightness. Our guide to buying a monolithic-clad house goes through what to check.
• A lender or insurer asks for one. Some do, particularly for plaster-clad homes built in the high-risk years.
• You've seen signs of a leak. Stains, soft skirting, cracks and a musty smell are worth having checked. Our guide to the signs your house needs recladding lists them.
• You're deciding between repair paths. A report shows whether the damage is contained or widespread, which is what separates a targeted repair from a reclad.

What it costs

Prices vary with the size of the house, the type of cladding, how easy the walls are to reach and how much testing is involved. As a rough guide, a report based on non-invasive checks, where nothing is drilled or opened up, often costs from a few hundred dollars to over a thousand for a larger house. Invasive investigation, where small holes are drilled so the timber itself can be checked, costs more. It's usually priced per job and often runs into the thousands.

These are general ranges, not quotes. The repair estimate inside a report is separate again, and our reclad cost guide shows what the repair itself typically costs.

What to do with the result

Findings usually point to one of three paths: a targeted repair, a partial reclad or a full reclad. Our guide to the signs your house needs recladding explains what separates them. Our guide to partial or full reclad goes into the choice between the last two. Give the report to anyone who will quote on the work, because a good quote is built on it.

Even a thorough report can't see everything. Auckland Council's guide to applying for a reclad building consent says the extent of any decay isn't known until the timber is exposed, and damaged framing has to be cut back well past the visible damage. That's why a reclad quote often has a provisional sum for timber repairs, an allowance that's adjusted once the timber is exposed. Our guide to how we quote a reclad explains how that works.

Reclad work needs a building consent, which we cover in our guide to reclad building consent in Auckland. Keep the report with your house records. It's useful to the next owner, and to the Council. If a reclad is next, our guide to how long a reclad takes covers the timeline.

Questions people ask

If the report comes back clear, is the house fine? It's good news for the walls that were checked, on the days they were checked. It isn't a guarantee for the life of the house, and anything that wasn't checked isn't covered.

Is a weathertightness report the same as a LIM? No. A LIM is a summary of the Council's records about a property. It doesn't test the walls. Our guide to reading a LIM report explains what it does show.

Do I need a report before I get a reclad quote? It depends on the house. Our guide to how a reclad is quoted covers the levels of investigation that come before a price.

What should I tell whoever prepares the report? What you want it for, and any limits on time or budget. MBIE's guide starts the same way, with a clear brief. A report written for a purchase decision looks different from one written to plan a repair.

Wondering whether your own house needs a report? Send us three photos for a free visual inspection: one of a window corner, one of the wall below a sill, and one where the deck or balcony meets the wall. Text them to 021 701 664 or email info@adronconstruction.co.nz, and we'll write back with a straight read on what we see and whether a closer look is worth it. It's a visual read only, so there's no site visit and no charge.

For the whole process, from first assessment to the Code Compliance Certificate, see our complete recladding guide, or read about how we approach residential recladding in Auckland.