ᐅ OSB Exterior Wall / Insulation: Vapor Barrier or Not?

Hello everyone,

I am new to the forum and have a question right away :-)

I lowered the lintel of my garage door opening by 1 meter (3.3 feet) because previously there was a roller shutter door with a height of 3.20 meters (10.5 feet), and now a sectional door with a height of 2.20 meters (7.2 feet) has been installed.

This opening, 1 meter (3.3 feet) high and approximately 2.50 meters (8.2 feet) wide, was double-layered with 22 mm (0.87 inch) OSB panels. They are flush with the reveal on both the inside and outside.

The facade will now be insulated, and I have a difference of opinion with the contractor regarding the use of a vapor barrier and adequate protection against moisture.

Is it sufficient to plaster the inside and insulate the outside only? Or does a vapor barrier still need to be installed here?

I hope you can help me! Thank you very much!

Best regards

It's a garage, right?

Regardless, OSB is also suitable as a vapor barrier; but in a garage, it doesn’t really matter anyway.

Exactly, it is a garage but located inside the house. So only the front faces outside. It is also heated.

So can the vapor barrier be "left out"?

Any ideas? :-)

Double-layered OSB is quite vapor-tight, but I assume parking a wet car in a heated room will create a high level of indoor humidity and corresponding condensation on the walls. Therefore, the garage will likely have some form of ventilation anyway, right?