Chimney Flue

[travismoshier]

How far can a chimney flue be offset? Here is a picture looking down the chimney. This chimney is used by a natural gas furnace.

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[Chad Fabry]

Not this far.

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This photo is one of hundreds I have that makes me believe that house inspectors (that's what we do..we're not most of the house inspectors) should get on roofs when it's reasonable to do so.

I'm positive that had I recommended a level II inspection because I inspected the roof from the ground, it wouldn't have ended in a client complaint. The fact is though, by getting on a 6:12 roof and poking around I saved my client the time, irritation and cash that arranging for another "expert" would have entailed. She got her estimate for free. It was a lot of money, the sellers wouldn't budge, she backed down, and I got another inspection.

As far as your photo goes Travis, it doesn't make me raise my eyebrows.

[kurt]

Depending on the size of the furnace and whether or not the chimney is on an outside wall, you may want/need a metal liner in there.

[Bill Kibbel]

That chimney flue originally vented an oil-fired system. It wasn't adequately cleaned when the conversion happened. Oil combustion deposits plus gas combustion condensate equals sulphuric acid. As Kurt said, it's also probably oversized now.

Here's your same picture, enhanced to see further down the flue. There's another offset that's more significant. There's also spalling starting on the left side of one section.

There's probably more further down. I would also have tried to take a pic from the bottom of the flue. If there's no clean-out, the flue connectors sometimes magically open up enough to reach in with a camera.

[Neal Lewis]

Originally posted by inspecthistoric

I would also have tried to take a pic from the bottom of the flue. If there's no clean-out, the flue connectors sometimes magically open up enough to reach in with a camera.

Guys, that seems like so much effort to do stuff like walk on roofs, take off chimney caps and take apart that dirty housey type stuff, like flue connectors.

Wouldn't it be a whole easier to just spend the time writing perfectly syntaxed CYA comments?[]

[travismoshier]

Originally posted by inspecthistoric

That chimney flue originally vented an oil-fired system. It wasn't adequately cleaned when the conversion happened. Oil combustion deposits plus gas combustion condensate equals sulphuric acid. As Kurt said, it's also probably oversized now.

Here's your same picture, enhanced to see further down the flue. There's another offset that's more significant. There's also spalling starting on the left side of one section.

There's probably more further down. I would also have tried to take a pic from the bottom of the flue. If there's no clean-out, the flue connectors sometimes magically open up enough to reach in with a camera.

You are right. The furnace was an old oil furnace converted to natural gas. It's the first one I've seen. The thing sounded like a jet was about to take off.

Thanks for everyone's input.

[Eric B]

Travis,

Did you see any mortar in the liner joints? I would say that there is none. If a metal liner goes in then it's not an issue.

I realize that most inspectors will not take off the flue cap but there can be a world of problems inside and considering the potential for down the road grief I think that it's worth the effort. And yes, it's above and beyond the "call of duty."

[Mike Lamb]

Travismoshier,

Did you take pictures of the exterior of the chimney? Was it experiencing problems? Brick and mortar failure? Efflorescence? Did this serve a fireplace?

How about vent problems near the furnace or water heater? Staining at the vent sleeves, etc.? How did the chimney look in the attic?

Was the furnace newly installed? Was the the chimney newly pointed or repaired?

Chad, the chimney flue in your photo had some exterior problems? Or was it a newer construction?

[Chad Fabry]

Chad, the chimney flue in your photo had some exterior problems? Or was it a newer construction?

There is significant efflorescence on the portion of the chimney housed in the attic. The house was constructed in 1990 and other than the chimney it's an uncommonly well built home.

[travismoshier]

Originally posted by Mike Lamb

Travismoshier,

Did you take pictures of the exterior of the chimney? Was it experiencing problems? Brick and mortar failure? Efflorescence? Did this serve a fireplace?

id="blue">There was mortar failure.id="blue">

How about vent problems near the furnace or water heater? Staining at the vent sleeves, etc.?

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How did the chimney look in the attic?

The attic wasn't accessible, there was just a 12" hole I could only fit my head in.id="blue">

Was the furnace newly installed?

This was an old oil furnace converted to gas. id="blue"> id="blue">

Was the the chimney newly pointed or repaired?

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Thanks for all the help!id="blue">