Chimney Repair & Masonry in Northwest Indiana
Water does the damage. Winter finishes it. The repair that lasts is the one aimed at where the water gets in.
By Mark Jason, owner of NWI Chimney Sweep · 34 years on NWI brick
Flashing repair and reflash
New step and counter-flashing where the chimney passes through the roof. The most common leak source we find.
Tuckpointing
Failed mortar ground out to solid depth and repacked with mortar matched to the strength of the original brick.
Spalled brick replacement
Bricks whose faces have blown off are cut out one at a time and replaced, not smeared over.
Partial rebuilds
When the top courses are loose, the stack is taken down to sound masonry and relaid from there up.
Leak tracing
A controlled hose test, section by section from the bottom up, to prove which part is letting water in.
Waterproofing
A vapor-permeable water repellent applied after repairs, so brick sheds rain but can still dry out.
Chimney flashing: where most leaks start
Flashing is the sheet metal that seals the joint between a masonry chimney and the roof deck, which moves with heat, wind and snow load. Done properly it is two layers. Step flashing is a series of L-shaped pieces, one per shingle course, lapped like fish scales up each side of the stack. Counter-flashing (also called cap flashing) is a second layer set into a groove cut in the mortar joint and folded down over the step pieces. The two layers are not fastened to each other, so the roof can shift without tearing the seal.
Why it fails
- It was never two layers. A single apron of metal face-nailed to the brick and sealed with roofing tar is the most common original-install shortcut.
- Tar and caulk “repairs”. Roof cement dries, cracks and pulls away within a few seasons, and each new layer hides the gap under it.
- Rust. Galvanized steel loses its zinc coating, pinholes at the bends, and stains the shingles below.
- Ice. Snow piles against the uphill face, melts from chimney heat, and refreezes at night, pushing water uphill under the metal.
- A re-roof that reused old flashing. New shingles, forty-year-old metal.
Signs inside the house
Brown rings on the ceiling near the chimney, peeling paint on the wall beside it, a damp smell in the attic, or dripping that shows up only when rain is driven by wind from one side. In the attic, dark trails on the roof sheathing next to the chimney are the giveaway.
Reseal or reflash?
If the metal is sound and correctly lapped but the counter-flashing has come loose from its joint, it can be re-set and sealed in the groove with a urethane sealant. If the metal is rusted through, tarred over, or was never stepped, it comes off and new flashing goes on. We form it in aluminum or copper depending on the roof and budget; lead is still seen on older homes and is left alone when it is working. The International Residential Code (section R1003.20) also requires a cricket when a chimney is more than 30 inches wide along its uphill face and does not cross the ridge: a small peaked saddle that splits water and snow around the stack instead of letting it dam there. A caulk bead cannot do any of that. It only moves the leak to next spring.
Brick and mortar: what freeze-thaw does
Freeze-thaw damage happens when water soaked into porous brick freezes, expands and shears the fired face off, which masons call spalling. Northwest Indiana gets repeated freeze-thaw swings through a winter instead of one long freeze, so the damage adds up quickly. Older brick chimneys, such as those found in Hobart, Lake Station, Munster and Highland show it most, usually on the top third of the chimney where there is no house heat to dry it.
Tuckpointing is the fix when brick is still sound but joints have receded. Joints are ground to roughly three-quarters of an inch, flushed clean, and packed in lifts with a mortar no harder than the brick around it. That last point is the judgment call: a modern high-strength mix against soft pre-war brick will hold, and the brick next to it will break instead.
Symptoms and what they usually mean
Each common chimney symptom points to a specific failed part, and the repair should match that part, not just the stain.
| Symptom | Likely cause | Proper repair |
|---|---|---|
| Stain on ceiling beside chimney | Flashing | Reseal counter-flashing or full reflash |
| Water in firebox after rain | Missing cap or cracked crown | Cap, crown seal or crown rebuild |
| Sandy, recessed joints | Mortar erosion | Tuckpointing |
| Brick faces on the roof or ground | Spalling from trapped water | Replace brick, then waterproof |
| Stack leaning or loose at the top | Joints failed through the full depth | Rebuild from sound courses |
What affects the cost of chimney repair
Chimney repair cost is driven by how much masonry is damaged, how high and steep the roof is, and whether scaffolding is needed. Tuckpointing is figured by the area of joints to be ground and repacked. Flashing depends on the perimeter of the chimney, the roofing material and whether a cricket has to be framed. Replacing a dozen spalled bricks is a different job from relaying the top six courses, and matching old brick adds to either. Starting prices for tuckpointing, flashing and waterproofing are published on the chimney repair pricing page.
Repair work does not include sweeping the flue or fixing the liner inside it; liner damage is handled as chimney relining, and the cap and concrete crown have their own page under chimney caps and crown repair. If the cause of a leak is unclear, we start with a chimney inspection before quoting anything.
Chimney repair and leak questions
Why does my chimney leak only when the wind blows rain from one direction?
Wind-driven rain gets behind loose counter-flashing or into open joints on one face of the stack. Vertical rain misses that gap. A hose test run one side at a time usually reproduces it within a few minutes. A chimney leak that follows wind direction is rarely the cap.
Is caulking around chimney flashing an acceptable repair?
As the only repair, no. Sealant belongs in the groove where counter-flashing enters the mortar joint. Smeared over the face of the metal or onto shingles it cracks with roof movement and traps water behind it. Proper chimney flashing relies on overlapping metal, not on sealant.
Can spalled bricks be patched instead of replaced?
Not durably. Once the fired face is gone the soft core soaks up water faster, and surface patches fall off with the next freeze. The damaged units are cut out and new brick of similar size and absorption is laid in.
How do I know whether tuckpointing is enough or the chimney needs rebuilding?
Probe the joints. If sound mortar is reached within an inch and the bricks do not rock, repointing works. If the mortar is powder all the way through or the top courses move by hand, those courses have to come down and be relaid.
Can masonry repairs be done during an Indiana winter?
Standard cold-weather masonry practice treats 40 degrees Fahrenheit as the line below which fresh mortar must be protected, so deep-winter work requires heated enclosures or waiting for a mild stretch. Flashing and temporary leak control can be done in most weather. Tuckpointing and crown work are best scheduled from spring through fall.
What is the white powder on my chimney brick?
Efflorescence: salts carried to the surface by water moving through the masonry and left behind when it evaporates. It brushes off, but it is evidence that the brick is taking in water somewhere above the stain. Finding that entry point is the real chimney repair.
Should a brick chimney be sealed with waterproofing?
With the right product, after repairs. A siloxane-type repellent soaks in and lets vapor escape. Paint and film-forming sealers trap moisture in the brick and speed up spalling. Waterproofing a chimney before cracked joints and crowns are fixed only seals the water in.
Does every chimney need a cricket behind it?
No. A saddle is needed when the uphill face is more than 30 inches wide and the stack does not sit on the ridge. Narrower chimneys shed water around the sides with correctly lapped back-pan flashing. The 30-inch threshold comes from the International Residential Code.
Stain on the ceiling by the chimney? Call before the next storm.
A person answers the phone from 7am to 9pm, every day of the week.
Call (219) 203-9797