Removing an old chimney during a renovation

Is anything still venting through it?

The first question is whether the chimney is still in use. Many older chimneys vent a furnace, a water heater or a fireplace. If any appliance still depends on it, an HVAC contractor re-vents that appliance through a new route before the chimney is touched. Removing a chimney that is still venting can let dangerous exhaust back into the house.

Does it carry load?

Chimneys are often built into the structure. Floor joists or roof framing may rest on the chimney or on headers built around it. Whether that is the case is confirmed from drawings or by a structural engineer, not assumed. If the framing depends on the chimney, the engineer specifies how it will be supported once the brick is gone.

Top-down removal

Chimneys come down from the top, one level at a time:

Working from the top down keeps the chimney stable and makes each load of masonry manageable. The exposed stack is dismantled in small lifts, with loose caps and damaged brick secured before lower courses are disturbed. At roof level, the crew coordinates closely with the roofer so the opening is never left unprotected while work shifts into the attic. Inside, each floor becomes a separate work zone. The area below the active section is kept clear, floor openings are guarded, and brick is lowered or carried rather than dropped down the flue. Debris is removed from each level as it accumulates because masonry weight can build quickly in a small footprint. Where floor framing, headers or fire blocking meet the chimney, mortar is cleaned away carefully enough to show how those elements connect before the next section comes down. A change in flue size, an offset or a concealed fireplace connection can alter the dismantling sequence, so the crew exposes and understands each transition instead of assuming the stack runs straight. Soot and loose mortar are contained at the source, while reusable access routes receive impact protection. The process continues level by level to the agreed stopping point, leaving any retained base stable and capped as directed. This measured sequence controls both gravity and debris, the two main risks that make chimney removal unlike ordinary partition work. Each completed level is cleared before work moves downward.

• The section above the roof is taken down brick by brick
• The crew then works through the attic
• Each floor below follows in turn, down to the basement or the agreed stopping point

Brick debris is heavy. It is bagged or carried in small loads, and floors along the route are protected against the weight and impact.

Roof opening and weather

Once the chimney is removed below the roofline, there is a hole in the roof. A roofer coordinates the patching and flashing with the removal plan, with temporary weather protection arranged where needed. Planning the roofer's visit around the demolition schedule is one of the most important coordination steps.

Brick, soot and dust containment

Inside the house, old chimneys release soot, mortar dust and loose brick. Each room the chimney passes through is contained with sealed poly and covered floors. The flue is often full of soot, so it is handled carefully to keep it from spreading. A permit may apply depending on the work; Toronto Building can confirm, and our demolition without a permit guide explains when one is needed.

When to bring in a professional

Chimney removal involves gas appliances, structure, roofing and heavy masonry in the same job. Bring in professionals for any chimney that runs through more than one floor, supports framing or still vents an appliance, and make sure the HVAC contractor, engineer and roofer are part of the plan.