Roofing cement has been applied over a chimney flashing in place of proper counterflashing. How should this be reported?

Roofing cement at a chimney is the most common field repair in residential roofing and the most reliably temporary. Proper flashing works because two overlapping metal pieces shed water while allowing the masonry and the roof to move independently. Cement instead bonds the two rigidly, and since chimney and roof expand, contract and settle at different rates, the bond cracks — usually within a season or two. Then it gets worse than doing nothing, because the cracked cement holds water against the joint and hides the deteriorating flashing underneath, so the leak develops out of sight and the sheathing and framing get wet before any stain appears inside. The inspector reports it as a temporary measure with a limited life and recommends proper base and counter flashing, without implying the chimney itself is failing.

Roofing cement bonds two elements that move independently, so it cracks as the chimney and roof shift. Once cracked it traps water and conceals the flashing beneath, making it a temporary measure that will fail and should be replaced with proper flashing.

Chimney-to-roof transitions require base flashing secured to the roof and counter flashing set into the masonry, overlapping without being fastened together so the two assemblies can move independently. Sealants and cements are supplements, not substitutes.

Tar Is a Timer, not a repair. It bonds two things that move, cracks, then hides the damage while water keeps going in.

Note that cement conceals the condition beneath it. That is what makes the finding worth reporting even when no leak is currently visible inside.

• •Accepting a cement patch as a durable repair
• •Escalating a flashing defect into a chimney rebuild recommendation
• •Clearing the detail because no interior stain is present yet