Chimney Flue Installation in San Marcos, TX

Sizing is governed by the appliance and code, not guesswork. For an open masonry fireplace, NFPA 211 and the IRC generally require the flue's cross-sectional area to be proportional to the fireplace opening — commonly around one-tenth for a round flue and one-eighth to one-tenth for square or rectangular flues, depending on chimney height. An undersized flue spills smoke and slows draft; an oversized one cools gases and accelerates creosote. We calculate from the opening and the appliance listing, then confirm against code.

Both, and they're linked. The 3-2-10 rule — flue terminating at least 3 feet above the roof penetration and 2 feet above any structure within 10 feet — exists so combustion gases and sparks clear the roof and so the chimney develops reliable draft. A flue that's too short can backdraft, pushing carbon monoxide and smoke into living space, and can drop embers onto nearby roofing. We set termination height to code as part of any new flue installation.

It depends on the system. Masonry flues built into masonry chimneys require a code clearance from combustible framing — typically 2 inches for interior chimneys and 1 inch where the chimney is on an exterior wall. Listed metal chimney systems carry their own clearance in the manufacturer's instructions, which the code requires us to follow exactly. Getting this gap right is the difference between a compliant install and a slow-charring fire hazard, so it's verified and documented.

Often yes — many flue installations are effectively relining an existing chimney with a properly sized, listed liner. A flue must be continuous, correctly sized, and rated for the fuel. If the existing masonry flue is cracked, unlined, or the wrong size, installing a UL-listed liner restores a safe, code-compliant path for combustion products. We inspect the existing structure with a camera first so the new flue solves the real condition rather than masking it.

Yes — our crews cover San Marcos's 4 ZIP codes across Hays County, including Texas State / The Square, Blanco Vista, Kissing Tree, plus the surrounding communities.

We offer same-week scheduling across San Marcos, booked by a real person in under two minutes, 7 AM to midnight every day.

San Marcos blends older housing near Texas State and The Square with new Kissing Tree and Blanco Vista construction in Hays County, and the older rental-heavy inventory drives much of our inspection demand. Tenant-occupied masonry fireplaces near campus often go years without service, so we lead with NFPA 211 Level 2 scoping for liner damage and creosote that deferred maintenance leaves behind. Willow Creek's established homes commonly present aging flues overdue for documentation. Chimney Flue Installation is part of keeping that local housing stock safe, efficient, and up to code.