I have a 90 year old brick chimney which vents a wood burning fireplace as well as the exhaust gases from the furnace and hot water heater (via an approx. 6″ dia pipe). There is no lining (i.e. the brick and mortar is exposed on the inside of the chimney) and there is no cap (i.e. rain comes right on in). It has also been painted and looks quite ugly.
I’ve been told I need to reline it if I want to use it for wood burning, but my intent is to install a gas insert and run a stainless steel vent pipe up the inside and cap it.
Someone else has told me I don’t need to reline it, that the chimney is sound, and that if I restore the exterior (clean off paint, tuckpoint) it will be in excellent shape (for gas usage).
I’ve even considered knocking it down from the roofline and rebuilding it.
Anyone have any suggestions about the best approach and how I can be certain of the need to reline/rebuild vs. restore?
Thanks!
David in Iowa
Edited 5/9/2005 10:15 pm ET by David Andersen
Replies
My chimney's almost that old, also. My advice is to line it for the separate devices. Easy, not necessarily cheap, but it'll preserve the old masonry. Gas devices don't heat the flue enough to prevent condensation, which will attack the chimney. You can also close it off better and worry less about carbon monoxide.
Are you saying to line it with a masonry liner before running the new stainless vent pipes, or that the stainless liner pipe is enough?
Thanks,
David
Around here, they won't allow it. I wanted to line the inside of my chimney to put in a range hood vent, but the city says no. They want me to bore a hole in my roof.
Quality repairs for your home.
AaronR Construction
Vancouver, Canada
Friend of mine here in N Idaho went the stainless steel pipe route- Wasn't cheap, but he only had to do it once and no worries thereafter, regardless what he exhausted up it- He's happy with his choice-
When you say stainless steel pipe are your talking about a smoke pipe (ie: uninsulated) or a pre-fab steel chimney (2" 2200-degree insulation)?
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
I'm not 100% sure, but I don't think I mean either. I'm talking about the sort of pipe that is run up the existing chimney for a direct vent gas fireplace insert. I'm assuming the best choice is stainless, but I'm not 100% sure of that either. The crux of my question is whether I can run the direct vent up an unlined brick chimney or not. If that is a bad idea, I need to either reline it or rebuild it. If I rebuild it, do I need to do it all the way down to the firebox, or is from above the roofline good enough? Since everything will be capped and the interior of the unlined chimney will not be exposed to gasses anymore, I'm assuming I can avoid the concrete lining. But I'm not sure and local contractors have given me conflicting opinions.
Thanks,
David
Are you going to continue to vent gas water heater and furnace into that chimney?--if so, I think you should line it, as another poster said, those units will put acidic condensate into the chimney and that will erode the mortar. If you are venting water heater and furnace somwhere else, then I don't see why you need to line the chimney and then put in a stainless flue--one or the other would suffice. If rebuilding (an optrion I, personally, would avoid), I think you should rebuild right down to the firebox, otherwise gases are still going to eat away the mortar in the chinmey that runs through the house and expose you to carbon monoxide as well as be a path for fire into your house.
Danno,The venting of the gas HW heater and furnace will erode the mortar even if those gasses are vented through a pipe? I have a 6" dia. pipe in one side of the chimney for these two units. It probably needs replacing, but assuming replacement, am I okay or do I still need a liner (or vent them elsewhere?)Thanks!David
I'm by no means an expert on this, but, no, I wouldn't think you'd need a liner if the water heater and furnace are connected to another pipe within the chimney. But I would agree with whoever said separate flue pipes for each would be good--I think you're okay with one flue for the water heater and furnace and another for the wood burning stove though. I would think the draft of the woodburner would be the least "consistent". Which reminds me--you are providing a source of outside air ducted right to the firebox, right? That way you don't create low pressure in your house when running the woodburner, which could cause backdrafts.
Actually I'm going to have a gas burner, not a wood burner, but yes, it will receive outside air directly and not any from within the house.
No, you do not have to "line" the chimney before puttting the metal pipe in. Your exist 6" pipe is a "liner". Don't think it is large enough or code approved to do all three gas units in it though.
However....that is not what you are asking. In theory, adding another "liner" be it stainless (my choice), or alum, should not present a problem. Check if there are any codes in your area that might prohibit different "types" of gas burning appliances from "sharing" the same chimney even though they are in separate flues. I would also put a cap over the top.
My intent would be to run two pipes, one for the gas FP and one for the HW/furnace exhaust. There is room for both. I'm mostly hoping I don't need to rebuild/reline (with cement) the chimney and it sounds as if that is what you are saying. Thanks!
"I'm mostly hoping I don't need to rebuild/reline (with cement) the chimney and it sounds as if that is what you are saying. "
No. A chimney is a structural masonry tube. A liner can be clay tile tube sections, or metal (SS or Alum etc). or pumped formed conc.
Unless the chimney is NOT structurally sound (ie falling apart, loose bricks, lots of cracks etc) there is no need to do anything with masonry.
Lining for gas appliances, assuming a STRUCTURALLY SOUND chimney, applies to the metal liners.
If the chimney IS structurally unsound, then you have a different can of worms.
We were faced with a similar dilema in the last house we lived in. I ended up replacing the old water heater with a direct vent one to get it out of the chimney.
It may be a small world, but I'd sure hate to paint it.
One of the best sources of information in a situation like yours would be your insurance company. They likely have standards for that sort of thing; they may even be more severe than the local building code. If you set up any appliance that could increase the risk of fire without meeting their standards, you are risking having them refuse to pay if there's ever a fire.
Generally, an open-flame heating appliance is rated for the type of chimney it needs by the maximum exhaust gas temperature. The actual appliance you plan to install will come with information to that end.
Remember that if you seal off the chimney and use it in effect as a vent-pipe chase, there will no longer be any air circulation in there to help dissipate the heat build-up. In a worst case scenario, the bricks of the chimney could theoretically accumulate enough heat to char or set alight the surrounding framing.
This is why heat sheilds placed behind woodstoves, for instance, must be set off the flamable surface they protect by an inch or so, and must also have free air-flow behind them.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
U can check archives for this topic but when i was researching doing my flue and googled flue liners i found a place in Great Britain that was alot cheaper than anything here.They sold all types but i was lookin at one pc. corrugated SS.They do what ur thinkin thousands times more over there and have it down to an art.
You should pick the gas insert you want to use FIRST, then line the chimney as specified for the insert. Not all inserts require stainless, which is much more expensive than the other type of metal (aluminum, I think).
Wood burning would be better with stainless steel.
Same for your furnace and water heater - see what they (collectively) require.
I looked into the same situation for our six fireplaces. There is a lot of controversy over chimney linings. The industry makes lots of money putting in chimney liners and is always trying to get codes passed to make more work for them. At one point they were even trying to get the clay liners banned so that people with clay liners would have to replace them.
I was looking at the Valor gas inserts, mainly because they are the only ones that fit our fireplaces. They are nice, but the cost of the liners pushed the whole project over the edge. Now I'm thinking electric logs.
I like barmil's suggestion. Run separate exhaust pipes up the chimney for each application. Not as likely to have a draft issue that way.
So not really a liner so much as separate exhaust pipes. That reduces the condensation inside the chimney, which should extend the life of the chimney. If you want to add another step, put a cap on there to keep the rain out.
Did you say you were in IA? Freeze/thaw land there. Condensation can be hard on masonry, especially in freeze/thaw land. :)
jt8
It's better to light a candle than to curse the darkness. --Chinese proverb