Fireplaces, Heating Stoves, Flues and Chimneys - Sealing off a chimey
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odawg
02-23-08, 07:38 PM
Hello all,
We have a first floor condo in an old Triplex. We recently had the crawl space insulated with an inch of spray foam to kill any drafts. Now we realize we left one huge whole unfilled - the old chimney.
From the ground floor, there is an access hatch into the chimey, and there is a lot of hot air blowing (quite hard) up the chimney. This seems to defeat the purpose of insulating the crawl space.
When we first moved in, our gas furnace exited into the chimney, so did the second and third floor furnaces. We've since installed a high efficiency condensing boiler that vents out the side of the building instead of the chimney.
The people on the third floor the triplex have installed a new liner, but the person on the second floor hasn't updated their system yet.
Can I seal off this chimney? What would happen if I stuck some insulation inside it at the first floor? I tried this for a second and it killed the draft quick, but then I considered that perhaps that up draft is important for exiting the fumes from the second floors furnace.
I want to keep the crawl space warm. We've gone to the trouble of spray foaming and putting down a plastic vapor barrier on the ground. This chimney is literally blasting warm air outside... uggh...
There is a nice flu vent in the crawl space, I'd love to just seal that up too... (along with the access to it on the first floor).
Any advice?
We have a first floor condo in an old Triplex. We recently had the crawl space insulated with an inch of spray foam to kill any drafts. Now we realize we left one huge whole unfilled - the old chimney.
From the ground floor, there is an access hatch into the chimey, and there is a lot of hot air blowing (quite hard) up the chimney. This seems to defeat the purpose of insulating the crawl space.
When we first moved in, our gas furnace exited into the chimney, so did the second and third floor furnaces. We've since installed a high efficiency condensing boiler that vents out the side of the building instead of the chimney.
The people on the third floor the triplex have installed a new liner, but the person on the second floor hasn't updated their system yet.
Can I seal off this chimney? What would happen if I stuck some insulation inside it at the first floor? I tried this for a second and it killed the draft quick, but then I considered that perhaps that up draft is important for exiting the fumes from the second floors furnace.
I want to keep the crawl space warm. We've gone to the trouble of spray foaming and putting down a plastic vapor barrier on the ground. This chimney is literally blasting warm air outside... uggh...
There is a nice flu vent in the crawl space, I'd love to just seal that up too... (along with the access to it on the first floor).
Any advice?
odawg
02-23-08, 07:44 PM
I'm quite positive, well not at all actually, but I do have this memory of the air in the furnace blowing back into the house at times too. What would cause this back draft and is it a problem ? I'm really not at all happy with this chimney blowing either way. It needs to get sealed somehow!
so-elitecrete
02-25-08, 06:06 AM
originally exhausting into the same chimney ? ? ?,,, not a code-approved practice these days,,, since you no longer use that chimney, i'd stuff f/g into my damper area,,, btw, backdrafts're not uncommon in any chimney.
hearthman
02-25-08, 07:56 AM
Get a pro in there before someone gets hurt! You need a Level II inspection to verify no combustion appliances are venting into this chimney including neighbors. Then you can discuss sealing.
Does you condensing boiler also make your potable hot water?
Have the inspector also measure and calculate for adequate makeup air for the boiler if it does not have a dedicated air supply.
The more you tighten the home, the greater the force of air infiltration and stack effect. Houses need to breathe, esp. down low. Seal it too tight and your home becomes a terrarium.
Do some research before acting.
Get a low level CO monitor, which means Not UL listed junk.
HTH,
Hearthman
Does you condensing boiler also make your potable hot water?
Have the inspector also measure and calculate for adequate makeup air for the boiler if it does not have a dedicated air supply.
The more you tighten the home, the greater the force of air infiltration and stack effect. Houses need to breathe, esp. down low. Seal it too tight and your home becomes a terrarium.
Do some research before acting.
Get a low level CO monitor, which means Not UL listed junk.
HTH,
Hearthman
odawg
02-25-08, 02:14 PM
You'd recommend paying to get an inspector to determine if there are appliances venting into it? Seems a bit excessive no?
Currently, the third floor furnace vents into an individual liner, and the second floor vents an ancient gas furnace directly into the chimney. Would his second floor vents depend on the updraft from the crawl space? Or would there be an updraft from his floor up regardless once I sealed it?
Its quite normal in this area to have under-code heating installations, as many buildings are 100+ years old. Its a real challenge to bring it up to date!
But this is definitely part of the research, and I'd love to know what would happen if I seal this chimney off WHILE the second floor continues to vent his gas furnace straight into it.
I like the CO monitor idea - going to do that.
Get a pro in there before someone gets hurt! You need a Level II inspection to verify no combustion appliances are venting into this chimney including neighbors. Then you can discuss sealing.
Does you condensing boiler also make your potable hot water?
Have the inspector also measure and calculate for adequate makeup air for the boiler if it does not have a dedicated air supply.
The more you tighten the home, the greater the force of air infiltration and stack effect. Houses need to breathe, esp. down low. Seal it too tight and your home becomes a terrarium.
Do some research before acting.
Get a low level CO monitor, which means Not UL listed junk.
HTH,
Hearthman
Currently, the third floor furnace vents into an individual liner, and the second floor vents an ancient gas furnace directly into the chimney. Would his second floor vents depend on the updraft from the crawl space? Or would there be an updraft from his floor up regardless once I sealed it?
Its quite normal in this area to have under-code heating installations, as many buildings are 100+ years old. Its a real challenge to bring it up to date!
But this is definitely part of the research, and I'd love to know what would happen if I seal this chimney off WHILE the second floor continues to vent his gas furnace straight into it.
I like the CO monitor idea - going to do that.
Get a pro in there before someone gets hurt! You need a Level II inspection to verify no combustion appliances are venting into this chimney including neighbors. Then you can discuss sealing.
Does you condensing boiler also make your potable hot water?
Have the inspector also measure and calculate for adequate makeup air for the boiler if it does not have a dedicated air supply.
The more you tighten the home, the greater the force of air infiltration and stack effect. Houses need to breathe, esp. down low. Seal it too tight and your home becomes a terrarium.
Do some research before acting.
Get a low level CO monitor, which means Not UL listed junk.
HTH,
Hearthman