Kearns Chimney Sweeping and Fireplace Repair

Draft is height and heat, and there is not much of either

A chimney works because a column of hot gas weighs less than the same column of outdoor air. The taller that column, and the hotter, the harder it pulls. Houses in this part of the valley are mostly single story or split level with modest roof pitches, so the run of flue above the fire is short by the standard of a bench house. Add to that the fact that this is the basin floor, where cold air settles and where the winter inversion lies thickest, and you have the least favorable combination there is: dense, still, cold air outside a stack with very little height to work with.

The result is rarely dramatic. It is a fire that never quite catches properly, a wisp of smoke rolling out at the top of the opening whenever the screen is moved, and a flue that loads up faster than the owner would expect, because slow, cool fires leave far more behind them than hot ones do.

The flue nobody counts as a chimney

Plenty of houses here have a masonry stack that was never really about the fireplace. It carried the furnace and the water heater, and in a great many cases it still carries the water heater alone, after the furnace was replaced with a high-efficiency unit that vents out through a side wall in plastic pipe. That leaves one small appliance venting into a passage with several times the cross-section it needs. The gas cools before it reaches daylight, condenses on the tile, and the acidic condensate goes to work on the mortar from the inside out. From the curb nothing looks any different. Inside the house, the way it announces itself is carbon monoxide spilling at the draft hood.

So if the furnace was changed out at some point and the water heater stayed on the old chimney, that flue is worth an inspection whether or not anybody has lit the fireplace in years.