Chimney Liner Installation in the Seattle Area, WA.

It is worth separating the two, because almost every other chimney problem is about the structure and this one is not. The brickwork, crown and flashing keep water out. The liner is the continuous passage inside that carries smoke, heat and combustion gases from the firebox to the top without letting them touch the masonry or the framing next to it. On older Puget Sound houses it is clay tile; on newer ones, or after a reline, it is stainless steel.

Three things put a flue out of service. Clay tiles crack – from a chimney fire, from a crown that let water in and froze, or simply from age and thermal cycling – and once a tile is cracked the gases have a route into the chimney cavity. Some older chimneys were never lined at all, which was legal when they were built and is not acceptable now. And a flue sized for an open wood fire is usually far too large for a modern appliance: an oversized flue runs cool, which means poor draft, condensation and creosote building where it should not.

Relining means running a correctly sized liner down the existing chimney and connecting it properly at both ends – insulated where that is required, terminated and capped at the top. The size is set by the appliance it serves, not by the chimney, which is why the first question is always what the flue is actually for. We also say plainly when relining is not the answer: a stack with structural problems needs those addressed first, because a new liner inside a failing chimney is money spent in the wrong order.