Sorry Ari, I might be sounding like the little boy in the story, The emperor has no clothes!
What if the system they want to educate us on is wrong?

Do you need to be an academic to know the problem, and is a academic "an expert"?

Building seams have been exposed to wind and rain for hundreds of years, in buildings built of untreated timber. I do agree about his comment on NZ Radiata Pine, as I have always believed our best wood is exported. Our pine now seems to have a very open cell structure because it has grown so quickly, hence it will take up moisture if exposed to it.

Take your average 100 year old victorian villa. Small to no eaves, large exposed faces, very exposed seams as in boxed corners, especially in two storied gabled villas, no back flashings, no silicone, no building paper and no rotting and built of untreated kauri which will rot quite quickly when exposed, especially prone dry rot. OK, they are as cold as heck in winter.

The reason for not rotting seems to be the top to bottom wall cavity ventilation, although I have recently been involved in a villa restoration and although the weather boards were only 12mm thick with as little as a 20-25mm lap and no weather grooves there was no sign of water staining which is associated with periodic water penetration and no rot. It did have borer though.
This villa was on a very exposed hill in the country. Looking from inside out through the weatherboards there was plenty of daylight showing hence you would expect that driven rain would have come in.

This breaks all the new rules yet it has stood the test of time for over 100 years????? Maybe it due to pressure equalisation, that is if the pressure behind the cladding is equal to that on the outside, water is not drawn in, even if there are gaps.

The new cavities E2/AS1 (the new acceptable solution for external claddings) calls for are NOT ventilated cavities, but in fact drainage cavities as there is no requirement to have vents at the top of the cavity, like in brick veneer constuction, only at the bottom, which will be prone to being blocked by insects, especially mason bees and wasps.

Having seen the verification method they are using to test claddings, my first reaction was that it didn't represent a real situation with unequal pressures on each side of the wall system that you get in a house, infact there was no internal lining and the test wall was open at the top to the back.