We've got our roof on and have windows being installed later this month - the installation includes air-tightness tape inside + outside so am expecting this to be pretty effective. House is ICF and we've applied tape around roof connections to walls - hope/anticipate that the main the walls/floor junctions will be fine. Trouble is that we have 3 doors inc the main entrance area (2m x 2.6m) areas that we won't have installed for some months yet but I'd like to see how the air-tightness is shaping
Yes if you tape the OSB in place correctly.
18mm OSB is generally considered airtight however I reckon 11mm is too if it is a well made board.
Don't bother getting a professional to do a trial. Rather buy something the car fan below. Bigger is better. Then screw and tape it into one of your sheets of OSB. Get some crocodile clips and wire and attach to your car battery.
They develop a howling gale compared to a proper blowerdoor. It makes it easy to find le