Chimney Repair Case Study: A Leaking Crown and a Cracked Liner

By Chuck Lee, owner of award-winning Imperial Chimney Sweepers in DeKalb, Illinois — in the chimney trade since 1987.

Illustrative example. This is a composite scenario written to show how we approach a job. It is not a real customer, a real address or a review, and the homeowner described here is invented.

This page follows one invented but realistic job from the first phone call to the finished chimney. We wrote it because homeowners often ask what actually happens during a repair, how we decide what a chimney needs, and why two chimneys with the same symptom can need very different work. Everything below is illustrative.

The call

Our imaginary homeowner, we will call her the owner of a 1960s brick two-story, noticed two things over one damp autumn: a musty smell near the fireplace on humid days, and a chalky white staining spreading across the exterior brick of the chimney. She had not used the fireplace in a year and was not sure it was even safe to light. Those two symptoms together, a damp smell and white staining, point almost every time to water getting into the chimney, so we scheduled an inspection rather than guessing over the phone.

The inspection

A proper chimney inspection works from the top down and the bottom up. On the roof we found the classic culprits: a chimney with no cap, so rain fell straight down the flue, and a concrete crown, the slab that seals the top of the masonry, cracked clean across with pieces missing. On the exterior, several brick faces had begun to spall, popping off in thin flakes where trapped water had frozen and expanded. Inside, a camera run up the flue showed stage-two creosote and, more seriously, a horizontal crack through one clay liner tile with a gap at the joint below it.

The white staining had a simple explanation once we saw the top: water was wicking into the masonry and leaving mineral salts on the face as it dried out. Our symptoms guide covers that staining, called efflorescence, in more detail. The damp smell was the same water sitting in a flue that had no cap to keep weather out.

Diagnosis and plan

With the findings in hand, the plan almost wrote itself, because water entry has to be stopped at the top before anything lower is worth fixing. We proposed, in order: a full chimney sweeping to clear the creosote so the flue could be worked on and re-inspected; a new crown to seal the top of the masonry; a stainless steel chimney cap to keep weather, animals and debris out of the flue for good; tuckpointing to replace the eroded mortar joints and the spalled brick faces; and, because the liner tile was cracked, a stainless relining to restore a sound, sealed flue. We explained which items were safety-critical, the cracked liner and the water entry, and which were about longevity.

The work

The job ran over two visits. First we swept the flue and set up protection inside the home. We removed the failed crown and poured a new one with an overhang and a drip edge so water sheds away from the brick instead of running down it. We rebuilt the spalled brick and repointed the open joints, matching the mortar as closely as we could to the original. Then we relined the flue with a stainless liner sized to the fireplace, insulated it, and fitted a stainless cap at the top. A final camera pass confirmed a clean, continuous liner with no gaps.

What this example illustrates

The point of this illustrative job is the order of operations. A homeowner seeing only the white staining might ask us to clean the brick, but cleaning does nothing while water keeps coming in from a missing cap and a broken crown. Likewise, relining a flue without stopping the water above it just traps moisture against the new liner. A good repair treats the chimney as one system, top to bottom. Costs for each of these services are listed on our pricing page; a real quote always follows a real inspection, never a description over the phone.