tmurray
SAWHORSE
Cost is a tricky one, I value high quality construction, but code approvals of cheap crap like OSB and plastic pipe should not be the way to lower costs, also Green and Energy codes have been a disaster in many cases creating the "sick home syndrome", in other cases causing buildings to rot out in a few years. When Vancouver had it's "leaky condo" crisis we were experiencing something similar here so I flew up to see what was going on, after reviewing the problems it became apparent that the code requirement to seal up buildings was the problem, after all the buildings didn't leak until they started sealing them up, at first they were requiring that 2" holes be drilled in the plywood sheathing to let air in but with all the insulation in the walls they started requiring rain screen construction, construction practices didn't all of a sudden become terrible over night, the problem coincided with code compliance.
Actually, the condos always leaked. the only thing that changed was that people wanted more energy efficient buildings (the code didn't deal with energy efficiency in 1970). So, designers increased the thermal resistance of the walls and air tightness of the building enclosure. The problem was that by reducing the thermal transmittance and airflow, they reduced the drying capacity of the enclosure without preventing bulk water from entering the building envelope. The architects made changes to their building enclosures without understanding how they worked, a dangerous thing for anyone to do. Now, we have rainscreens required in areas that meet certain precipitation rates (I'm in one), because the architects did something stupid, the insurance industry got involved and asked; "why are they allowed to do this stupid thing, it's costing us a lot of money", so it ends up in the code. Things don't end up in the code "just because" (at least in ours). Generally, someone has to die, severely injured or, as in this case, a systematic industry failure.
"sick building syndrome" is the same thing. If you make your building more airtight, you need to provide mechanical ventilation. I love hearing the argument from everyone that doesn't understand how ventilation works; " you're making the building more airtight just to ventilated it with fans?". Yes, because I can turn a fan off and on. I can run a fan at different speeds if I need more or less ventilation. It's the same thing as having a window that you can close or open or simply a hole in your wall.
It's not the ventilation that's the problem, It's the lack of control.
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