Penetrations of the vapour control layer need special attention regarding a permanent functional sealing.
Some manufacturers are offering special grommets for the sealing of HRV ducts. Most of them are great but beside the cost factor, who stocks all the different sizes permanently?
I did plenty of attempts how to seal the HRV ducts on an easy, affordable and save way. At the end, I found a solution by optimising the so called "flake bonding". By applying a total of 3 layers of air tight tape, I can ensure a permanent air tight sealing now.
It takes roughly 10 minutes to seal one duct. All what I need is roughly 1.5 meter of suitable air tight tape (no Kraft paper or silicone coated tape please), partly skilled fingers and common sense.