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. Prime 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 looks like a chimney problem but usually isn't. A fireplace that smokes only when the kitchen hood is running, a flue that drafts fine on a calm day but spills when the house is buttoned up, a basement appliance that backdrafts in winter — these are makeup-air problems. The house is depressurized below what the flue can overcome, and air (and combustion gas) flows the wrong way. Diagnosing it requires putting the house into worst-case depressurization — closing doors, running every exhaust device — and measuring whether the combustion appliance zone (CAZ) still drafts or spills. Without that test, you're guessing, and guessing about backdrafting combustion gas is dangerous.

The correction matches the finding. If the fireplace itself is starved, we run a dedicated outside-combustion-air (OCA) intake to the firebox so it draws makeup air from outdoors instead of the room — designed in, not bolted on. If the whole house is the problem, we add 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 depressurize the combustion zone when those run. Where return-duct leakage is depressurizing a zone, we seal it. The right fix is the one that addresses how your specific house loses its balance.

A particularly common version is the orphaned water heater. When a high-efficiency furnace is installed and switches to sidewall PVC venting, it 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. We re-line and resize the flue to the single appliance so it drafts safely. This is a CAZ failure hiding as a venting problem, and it's exactly the kind of cause-level diagnosis a premium brand catches.

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

PCE 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 is constant. We document the testing 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. If your fireplace or appliances draft inconsistently or you've had unexplained spillage, it's likely a makeup-air problem worth measuring.