Tried using foam backer rod on a crown molding gap and it backfired

Had a tricky ceiling gap last week on a job in an old house near downtown. The crown molding had a 3/8 inch gap in one spot and I thought foam backer rod would be a quick fix before caulking. Thing is the backer rod absorbed moisture from the caulk and swelled up overnight, pushing the whole seam out of shape. Had to rip it all out and redo it with paper tape and joint compound instead. Anyone else had this stuff mess up a ceiling detail?

2 comments

2 Comments

jordanl821mo ago

Backer rod's for concrete joints, not trim work.

wesley_thompson1mo ago

Backer rod's for concrete joints" is such a specific thing, but @jordanl82 you're right, people grab the wrong stuff all the time.