Personal opinion as a layman / ordinary member of the Public.
It is in my view that much of the buck stops with BRANZ (Building Research Association of New Zealand) of the time for approving the products and construction methods associated with the leaky homes crisis in the first place. Particulary pertaining to the period starting around the mid-90’s and ending around ~2005.
I am surprised back then that not more scruntiny were directed towards BRANZ and their appraisal process of the time.
It’s also in my personal opinion that some commercial players in the industry later milked the situation for what it’s worth for their own financial gain adding insult to homeowner injury by employing fear and resulted in my view, needless regulatory capture so much so that Homeowners were no longer afforded the self determination nor the right to reclad a given place themselves, significantly increasing both the bureaucractic and financial burden of getting their own homes up to a better more durable and livable standard on their own accord.
Is it is further to my opinion that a lot of needless reclads have occured when more targeted solutions for certain situations could have sufficed.
Pertaining to some monolithic cladding methods… Given New Zealand’s climate, in particular rain full and use of under-treated timber, there was insufficient ability for moisture to escape at sufficient volume to avoid damage from moisture build up over time. This was in my view particularly the case due to insufficient specifications regarding protecting window flashings and protecting penetrations for services (such as pipes) allowing additional moisture to seep through into the building envelope with no means to escape but to effectively settle and accumulate at the bottom of the timber wall framing there by rotting out the bottom plate member.
While some cladding manufacturers had specified an air gap at the bottom edge (slight overhang of the wall frame over the foundation), it is in my opinion this alone was not sufficient to allow enough moisture to be removal. It was also the case that builders did not even bother to leave this gap as per mandated by the cladding manufacturer.
Now it would be easy to blame homeowners / home buyers (“Consumers”) in this situation but give the prevailing industry wisdom of the time, the public were assured by those that were entrusted with protecting the public that things were OK.