Documented Chimney Inspections for Murray Homes

The shared-flue problem in post-war houses

Older Murray homes were often built with one masonry chimney serving more than one appliance. A furnace and a water heater vented into the same flue, sized for the combined output of both. That worked for as long as both were there.

Then the furnace gets replaced with a modern high-efficiency unit, which vents its own exhaust out through a plastic pipe in the wall and no longer uses the chimney at all. The water heater is left behind, on its own, venting into a masonry flue built for something several times its size. This is what is meant by an orphaned water heater. The exhaust is too small and too cool to drive that flue, so it stalls, condenses on the tile, and in the worst case spills back into the basement. Carbon monoxide is a real possibility, and the homeowner has no reason to suspect anything, because the furnace upgrade was an improvement.

It is one of the most common serious findings we document in this part of the valley, and the fix is straightforward once it has been identified: an appropriately sized liner for the appliance that is actually connected.

Inspection levels, briefly

Level 1 is the annual check of what is readily accessible. Level 2 adds a camera scan of the flue and access to the spaces the chimney passes through, and it is the correct scope for a property sale or any change of appliance. Level 3 involves opening up concealed construction and is reserved for defects the camera has already suggested.

What a sale-related inspection should give you

• Video of the flue interior, not a description of it.
• A clear statement of which appliances are connected and whether the flue suits them.
• Condition of the crown, cap, flashing and the masonry above the roof line.
• Anything that needs doing before the next fire, separated from anything that can wait.

That separation matters. A buyer reading a report cannot tell an urgent item from routine wear unless someone says so plainly, and vague reports cost sellers money in renegotiation over things that were never urgent.