This vapour permeability experiment has generated a bit of interest so I thought I’d post a ‘one-month’ update. Click here to see the original post about the experiment.
Anyway, here’s the update. I put 125ml of water in the containers on 03/08/19. The attached video shows the change in water level at 03/09/19. Original and new water levels are indicated with a black marker line.
From left to right on the video the pliable membranes tested are:
- Thermakraft Covertek 407.
- Bradford Enviroseal Proctorwrap – residential walls.
- Bradford Enviroseal Proctorwrap – roof sarking.
- Polyweave foil (non vapour permeable).
As you can see, after a month, the vapour permeable membranes are doing their job. The non-vapour permeable polyweave foil has done nothing.