My shop has a masonry chimney (chimney block with clay liner) installed on the inside wall. The existing construction has OSB wall what butt flush with the chimney, as does the ceiling. I'm about to blow in cellulose in the ceiling and it dawned upon me that I might have some clearance issues. Is the OSB on the walls or ceiling a concern? If so that's a hard fix. Any issue with cellulose in direct contact with the masonry. I can build a barrier to maintain clearance but it is cramped for space and I don't want to mess with it if it's not a concern.