Downdraft Repair

A modern home can be too tight for its own fireplace. When exhaust fans, the dryer, and the HVAC pull a sealed house negative, the fireplace and other combustion appliances can't get the air they need — so they draft poorly, spill smoke, or backdraft combustion gases into the living space. Texas Chimney Experts diagnose and correct these combustion-air and makeup-air problems at the level of the whole house, not just the firebox, with the measurement discipline that finds the real cause. Premium here is an engineered fix for an invisible, sometimes dangerous, problem.

The symptom presents as a chimney problem but usually isn't. A fireplace that smokes only when the kitchen hood runs, a flue that drafts fine on a calm day but spills when the house is buttoned up, a basement appliance that backdrafts in winter — those are makeup-air faults. The house is depressurized below what the flue can overcome, and air (and combustion gas) flows the wrong way. Diagnosing it means putting the house into worst-case depressurization — doors closed, every exhaust device running — and measuring whether the combustion appliance zone (CAZ) still drafts or spills. Skip that test and you're guessing, and guessing about backdrafting combustion gas is dangerous.

The correction is matched to the measured finding. A starved fireplace gets a dedicated outside-combustion-air (OCA) intake run to the firebox so it draws makeup air from outdoors instead of the room — designed in, not bolted on. A whole-house depressurization gets a passive makeup-air opening, or, where exhaust loads are heavy, a motorized makeup-air damper interlocked to the range hood or dryer so the house can't pull the combustion zone negative when those run. Return-duct leakage depressurizing a zone gets sealed. The right fix is the one that addresses how your specific house loses its balance.

A particularly common version is the orphaned water heater. A high-efficiency furnace installed on sidewall PVC venting often leaves a lone water heater venting into an oversized common flue it can no longer keep warm — so that flue stops drafting and the water heater spills CO. The flue is re-lined and resized to the single appliance so it drafts safely. That's a CAZ failure hiding as a venting problem, and exactly the kind of cause-level diagnosis the measurement catches.

The verification standard mirrors the CO work: after the correction, the worst-case depressurization test is re-run to confirm the CAZ now drafts and doesn't spill, and the result documented. A makeup-air fix not re-tested under worst-case conditions is unverified — and when the failure mode is combustion-gas spillage, unverified is unacceptable. The measured before-and-after is the deliverable.

TCE performs combustion-air and CAZ correction across the continental US and the four Texas metros to one instrument-based standard. Home tightness, climate, and exhaust loads vary widely; the diagnostic and verification discipline stays constant. The testing is documented so the result is verifiable for you and your insurer.

This work protects health and makes the fireplace actually usable — no more smoke when the hood runs, no winter backdraft, no orphaned appliance spilling CO. Fireplaces or appliances that draft inconsistently, or any unexplained spillage, point to a makeup-air problem worth measuring.