Hi I have these panels of XPS covered with OSB. The OSB is shiplaped and is a very tight fit. However the 2 inch thick XPS behind it has 1/8th gaps at the seams. Is it necessary to fill these seams if the OSB is tightly sealed over the seams. It is below grade on an interior walkout blockwall foundation that is eight feet tall. Foundation is concrete block (8 inch) with full bricks mortared on the exterior. The panels are 2 inch of XPS and about 1/2 inch of osb with shiplaped edge on the osb. It is actually all already on the walls and I was posting to see if it would be worth the effort to take down the panels and seal the seams with the spray foam or just make the osb airtight. I'm worried about the 1/8 " gap letting moisture vapor through to the OSB and creating a mold issue. I don't know enough about this stuff and convection currents to know if that is a realistic concern or not. Here are some pictures.