Rookie mistake I keep seeing with chimney flue measurements

I was up on Mrs. Henderson's roof last Tuesday out in Oak Park and noticed the flue liner was about 3 inches too short. A lot of new guys think the liner just has to reach the top of the chimney, but it actually needs to stick out past the crown by at least 2 inches per code. I learned that the hard way back in 2018 when I had to redo a whole job because water was running right down the side of the liner. Has anyone else run into this on older homes with those recessed crowns?

2 comments

2 Comments

pat_hall8729d ago

Three inches? I've seen liners hanging out way less than that and they were fine for years. Might be one of those things that sounds worse than it really is.

daniel51129d ago

So are you saying people are just being overly cautious about this? Because I've seen a few jobs where the liner wasn't even visible and it still leaked after two years. @pat_hall87, what kind of soil conditions were you working with when you saw those liners holding up fine? I'm trying to figure out if there's a specific situation where that extra hanging material actually matters, or if it's just one of those rules that sounds strict but doesn't really cause problems.