Do I really need a chimney liner?

Question

I'm buying a duplex and the home inspector brought up a concern about the furnaces and hot water heaters venting into the old chimney on the house. There are no fireplaces. I've never heard of this before, so am hoping some of you can tell me if this is really a big deal or not. He explained that over time the gas going into the chimney can erode and deteriorate the inside of the chimney and cause a lot of damage. He also said another concern is these gases leaking into the house. He recommended having a chimney expert come out and give a quote on putting in a stainless steel liner.

Should I ask for the seller to have a liner installed? Or just use it as a negotiating point because it's not really an issue?

Is this a normal issue in a house built in the 1930's? Has anyone actually had a problem caused by the lack of a chimney liner?

Thanks!

Should I ask for the seller to have a liner installed?  Or just use it as a negotiating point because it's not really an issue?

Is this a normal issue in a house built in the 1930's?  Has anyone actually had a problem caused by the lack of a chimney liner?

Thanks!

Bill Gulley · Answer

Only read this, not other comments, it really depends on the construction of the venting chimney some are fine for a hundred years, it's the back pressure or flow of gases that really matters. What you may find is that inspectors or fix it guys may expose potential problems as an opportunity for work, so second or third opinions might be in line.

Frankly, it may not be an issue at all, if it "ain't broke, don't fix ix it!

Inspectors should have carbon monoxide meters to read any back flow of a chimney, lined or not, if it isn't flowing properly, feeding back gases, get it fixed.

Yes, a liner will solve many issues, they lock in place and are fairly air tight to achieve better air flow than an old brick or stone chimney, capped properly at an elevation above the roof line they will solve emissions better than a masonry chimney.

Yes, masonry leaks gases, but the real hazard might be questionable, the height of the chimney and the :geometry" involved, attic ventilation play a role in the safety aspects.

I'd just suggest a second opinion, you could be had by an inspector being a little over the top, they do try to limit their liability as to their inspections, so some things should be taken with a grain of salt.

So long as it passes code. that's the hurdle.

Might ask the gas company to inspect, that should be free! If they recommend repairs or improvements, I'd go with the utility inspector's advice. :)

Steve Babiak · Answer

Although Bill Gulley raises one problem to consider with back drafting (where exhaust gases are sucked back in due to the need for more of an air supply to perform proper combustion), that problem is better solved by using an "air make up system" such as a Skuttle to supply additional outside air without having to pull it through the chimney.

But CO (carbon monoxide) gases are a real problem with heating systems, and the exhaust system (including any chimney) must be capable of preventing any leakage of that exhaust into the building. CO detectors and alarms are now required by code in many places due to this issue. And my insurance company requires them regardless of local code!

Alex M. · Answer

Good luck with the negotiations. It would be great if the seller does take care of the issue for you. For future reference, I would recommend that you look into HVAC guys who have BPI certification (google it). There are often a lot of issues in older homes. Water heaters and furnaces are often pretty poorly vented. When combustion appliances are involved, it is better to be aware of these than faced with a situation down the road.

Jacob Elbe · Answer

All,

Thanks for all the input!  I called a few people regarding installing the liner and quotes came in quite the range!  A chimney guy estimated $1500 without see it, while an HVAC guy said he installs them for $560.  So I'm including it in my home inspection response to the seller and asking for them to just have a liner installed.  We'll see if they go for it.  They've already come down $10k on their original asking price from $75k to $65k, but I know they want to sell.  Wish me luck!

Rob K. · Answer

My understanding of chimney liners is that as furnaces became more efficient over the years, there's less heat going through the chimney and it has an effect on condensation which will ruin the chimney from the inside out.

I have helped install a chimney liner on two occasions. Both times, I was the guy inside pulling a rope to pull the liner down the chimney while the HVAC guy was on the roof shoving the liner down the chimney. Both times, it was fallry easy and the liner went down the chimney in less than 15 minutes.

You can probably find a small time HVAC guy (or a guy who works for a company and does side jobs) to install a liner for $200-400. Not a big deal.

Jon Holdman · Answer

@Jacob Elbe I honestly have no idea of the seriousness of this issue.  Get a HVAC guy out there to take a look.  Most property inspectors are generalists who can point out potential issues but aren't fully able to say if its a problem or not.

You could also call the city building department and speak to an inspector.  They're familiar with construction in the area.

Bill Gulley · Answer

Yes, good point Steve, and backdrafts can be caused by the height of a chimney not exceeding that of a roof line in proximity to the stack, which can cause the air pressure to change. An insert can aid in correcting the draft.

John Whittle · Answer

It also depends on the type of furnace. 60% 70% are generally fine, they are old natural draft type.  80% the kind with a motor that gives the exhaust a little push but still vent in metal flu. The chimney has to be lined.  Which can be a clay liner that a lot of chimneys have.  Can't hurt to check if you find chunks of bricks you might just consider getting a 90% furnace and power vent water heater and abandoning the chimney.

Patrick Page · Answer

just bought a 5 unit. all seperate heat.  One unit had an old furnace that the seller is going to replace and Line The Chimney It just makes good sense.

Jacob Elbe · Answer

Thanks @Jon Holdman !

Is it something I need fixed immediately?  Obviously if I can get the seller to pay for it I will, but if not then what's the risk if I wait until next summer or even a few years before I have one put in?

Do I really need a chimney liner?

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