Learned a new way to spot hidden chimney leaks from an old mason in Vermont

I was up on a job in Burlington last month and an 80-year-old mason named Hank showed me how to find cracks by feeling for cold air with the back of your hand on a windy day. Found three leaks I missed with just a flashlight. Anyone else use this trick or got other low-tech methods?

2 comments

2 Comments

thompson.nathan25d ago

Hank's trick with the back of your hand is solid, but I gotta ask - did he mention checking during a steady rain too? I've found that water dripping down a chimney can hide air leaks pretty well, and a dry windy day only tells you half the story. My granddad used to say a wet rag on a stick is better than a flashlight for finding damp spots that turn into cracks later. Seems like these old-timers always have a method that beats the fancy gear, but they never tell you the full setup until you've been on their crew for a decade. What else did Hank teach you about reading the brickwork itself before it even gets cold out?

dixon.spencer25d ago

@thompson.nathan yeah the rain trick is huge. Hank always said to wait until a steady drizzle and then run your hand along the mortar joints near the chimney cap. Water seeping in will feel colder than the damp bricks around it. He also swore by tapping on the bricks with a screwdriver handle - a hollow sound means moisture got in behind the face and froze, even if the surface looks fine. That wet rag trick your granddad used is genius too, gonna try that next time.