Weather Tightness – Leaky Homes


The period of 1990 to 2004  became the perfect storm in the residential building industry … deregulation, new untested products, private certification, etc. Leaving behind an era which has been costly to homeowners, taxpayers and ratepayers. The “Leaky Home” period!

The words “Leaky Home” scare most people, purchasers, sellers, real estate agents. While many have been identified, there are still many which have not.Then there are those that have been repaired which continue to leak.

Proper due diligence when purchasing a property that was constructed during this period is paramount. A standard Pre Purchase Report would identify that there may be an issue that requires further investigation, over the last 12 months my records show about 10-15% homes that I reported on had this requirement.

Remember not ALL houses built in this era are BAD!

A survey for weather tightness involves several steps, the first is an assessment of the plans of the house, to determine the era, how it was constructed and what products were used.




Floor plan -framing and cladding



Moisture Readings

Moisture Testing is one tool available to help analyse a building.

There are two types of moisture readings, the first is an indicative reading of the subsurface, this is used to scan an area to help identify an area for further investigation (See photos below). The second is a Moisture Content reading of the actual timber, this is given as a percentage (%).

A surface reading (141) on a dry piece of untreated Pine.
A surface reading (197 At Risk) on a piece of untreated Pine. This had been soaking in a bucket of water for 24 hours.



Surface readings are only indicative, the can be affected by items within the wall or substrate … wire netting in stucco, copper pipes, steel braces in framing, etc.

In the case of the Protimeter Surveymaster pictured here the give a “reading” which is on a continuum from 71 to 999

71 – 169 Dry, 170 – 199 At risk, 200 – 999 Wet.

A cluster of “At Risk” and “Wet” readings would indicate the need for further invasive investigations.





Moisture Readings % and their Definitions


Moisture Content (11.5%) in a piece of untreated Pine
Moisture Content reading 26.1%. This piece of untreated Pine had been soaking in a bucket of water for 24 hours.












Deep internal moisture testing using long probes


Process of Investigation

Often the design and materials used throw-up the “red flags” which indicate further investigation is necessary. Weather tight issues are generally a combination of factors, for example, non-treated timber by itself in a dry environment will last for a long time, but add in poor flashings in a high wind zone which allow for moisture ingress, then there is potential for an issue. Studying the design plans helps understand where potential issues could arise, what materials should have been used … this helps as we can look up the manufacturer’s specifications of how this product should have been installed.

Then a physical survey is undertaken to identify potential problem spots, eyes and nose are sometimes the best tools at identifying areas, then surface moisture testing will narrow these down, along with dye testing, invasive moisture readings and sampling of timber to determine degree and type of decay.

Invasive Testing
Moisture Testing















Decaying Structural Timber 


Poor Flashing Design
















Once it is established where and how the leaks are occurring, then the process of Remediation can get started. This will vary from house to house and invole a number of Consultants, Trades and Council Staff.



More information can be found on the MBIE Weathertight website here.


If you have any questions about your own situation please do not hesitate to call (0274 572 285) or email