Chimney Masonry Repair in Woodland Hills: Written Report, Licensed Technicians

The call came from a homeowner on a tree-lined street near Tujunga Village. She'd bought a set of vented gas logs to replace her wood-burning setup and hired a plumber to run the gas line. The plumber took one look inside the firebox and stopped work. Several mortar joints along the back wall had eroded to a depth of nearly an inch, and a vertical crack ran from the smoke shelf down to the firebox floor. He told her the chimney needed masonry work before any gas appliance could go in safely. She called us the same afternoon, worried the whole project was about to stall indefinitely.

Her situation is common along the Ventura Boulevard flats and the Moorpark Street corridor, where ranch homes built in the 1950s and '60s still have their original brick chimneys. Decades of small earthquakes and seasonal temperature swings weaken lime-rich mortar. Homeowners converting to gas logs often discover this damage only when an installer or inspector gets a close look at the interior masonry. The fireplace looks fine from the living room, but inside the flue system, joints are hollow and bricks shift under light pressure. That gap between "looks okay" and "actually safe" is where our chimney masonry repair work begins. If you're facing a similar situation, our full range of chimney repair services covers exactly this type of project.

We started with an NFPA 211 Level 2 inspection, which is required any time you change the fuel type in a fireplace. Our technician ran a camera through the full flue and documented the damage: deteriorated mortar joints in 40 percent of the firebox courses, a hairline crack pattern consistent with earthquake micro-movement, and minor spalling on three bricks near the damper. The smoke chamber had the same story. None of this was visible from the hearth. We recommended tuckpointing with Type N mortar, which has the flexibility these older chimneys need. Type S mortar is stronger in compression, but its rigidity makes it a poor match for masonry that has to absorb seismic movement without cracking again next year.

After grinding out the failed joints to a minimum depth of three-quarters of an inch, we repointed every affected course and parged the smoke chamber with a heat-rated refractory cement. Once cured, we applied a siloxane-based waterproofing treatment to the exterior crown and upper courses to prevent moisture from restarting the cycle. The entire job took two days. The homeowner's gas log installer came back the following week, passed his visual check, and completed the conversion. If your chimney needs more than joint repair, we also handle full chimney rebuilds for structures with extensive brick failure. For technical guidance on mortar selection and masonry standards, the Masonry Institute of America technical resources are a reliable reference.