In some corners of the construction community there is still a lurking belief that a leaky fabric is needed in order to ensure good indoor air quality.
But gaps and cracks are random, and the air flow through them, even more so. Believing a leaky fabric will contribute usefully to indoor air quality is an act of blind faith.
You don’t know how much air will flow on any given day (temperature and wind are not in the gift of the construction team….) You don’t know where the holes are, you don’t know where the air will enter and leave. Will it come in through the living spaces, and exit via the wet rooms? Or do the opposite? Who knows?
I pulled some of the evidence on how (little!) leaky fabric contributes to indoor air quality in a blog post for SIGA, along with some suggestions about how to get the air flow you want, where you want it. Spolier: its not by slovenly construction!