Mechnical ventilation is a no-brainer

20 August 2020 by Jason Quinn
Fresh air is good for people but also the buildings


I grumble about BRANZ, but the scientists working there are good people trying to fix problems with how we build. Unfortunately they are hamstrung by needing to do that while not changing how we build.

That’s pretty much impossible. How about instead we just fix the Building Code? Proper air control layers and continuous mechanical ventilation would be a good start.

Source: BRANZ. Condensation inside a metal-clad roof cavity shortly before completion

This article from BRANZ about actively ventilating roof cavities to prevent moisture build-up makes a quiet passing reference to a school with issues I am well-aquainted with. I was asked to investigate its roof that produced rain inside on sunny days, only to be told to stop. I hope this solar fan idea works, as I believe this will be the fourth winter kids have sat under a new roof that drips water on their desk.

They really should fix the roof—as in replace it with one that will work—instead of installing more ventilation. That’s just a bandaid in my view.

It is funny to see BRANZ mechanically ventilate the roof cavity, while its official position remains that the inside of the school (and any other building) needs none. I’ve had spirited arguments for years with many in the local building industry that all homes/schools/offices should have continuous mechanical ventilation. SILLY IDEA, they said.

But fresh air is vital for buildings as well as people.

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