New build - fireplace/chimney issue

1,933 Views | 14 Replies | Last: 4 yr ago by Aggie1
GBMont3
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AG
Built house this year. Wood burning fireplace with gas starter.

Flue is OPEN. Chimney is not drawing smoke efficiently. It's not all billowing into the house of course but plenty of smoke is visibly entering our living space and tripping the smoke alarm.

Any suggestions as to what the issue may be? We've notified the builder but I'm stumped as to what the problem is? Could the flue be undersized relative to the firebox?
Sims
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AG
Is the furnace on? Is the fresh air vent to the furnace properly sized? Do you get less smoke in the house when there is a window open?
Hold on honey, there are people on the internet that are wrong.
maddiedou
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AG
Same issues here but I was the builder I am about to extend our chimney about 4 more feet

Mine only does it when the wind is blowing hard
maddiedou
Win At Life
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AG
Is your fire hot enough to create a draft? Smoldering fires won't. If your fire is hot enough it's almost impossible not to create a strong draft. But even under the best conditions a smoldering fire will probably have some smoke coming in. It's all a matter of degree.

The chimney box and flue are all sized properly per UL listings and crap, so that's probably not the problem unless they just left something stuffed in the flue or you have a bird's nest.

Houses are made tighter today than they used to, but it's still almost impossible to completely reduce infiltration enough to choke off a chimney with a good, hot draft.

It is, however, not terribly uncommon to have a chimney that's too short. Check to see if the wind is coming from the other side of the house. It tends to bounce up the roof and circle back down the leeward side. If the chimney does not stick up high enough, this will be forcing air back down the chimney making a draft hard (but not impossible) to maintain. My dad had this problem and raised his chimney about 4 feet.
GBMont3
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AG
I'm wondering a bit about chimney height. Our builder shortened it vs original design for aesthetics (his idea, not ours) and perhaps that's the issue.

Issue abates when/if we open a window or the back door.

Low/smoldering fire not the issue - this occurs while we've got the gas starter rolling pretty good too.

JP76
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GBMont3 said:

I'm wondering a bit about chimney height. Our builder shortened it vs original design for aesthetics (his idea, not ours) and perhaps that's the issue.

Issue abates when/if we open a window or the back door.

Low/smoldering fire not the issue - this occurs while we've got the gas starter rolling pretty good too.





Foam insulated house ?

Does your fireplace have a fresh air intake vent on the exterior ?
Win At Life
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AG
JP76 said:

GBMont3 said:

I'm wondering a bit about chimney height. Our builder shortened it vs original design for aesthetics (his idea, not ours) and perhaps that's the issue.

Issue abates when/if we open a window or the back door.

Low/smoldering fire not the issue - this occurs while we've got the gas starter rolling pretty good too.





Foam insulated house ?

Does your fireplace have a fresh air intake vent on the exterior ?
Foam insulation is not an issue. Infiltration is still present no matter how tight they tell you the house is. Bathroom vents, kitchen exhaust, doors, attic stairs and others. The dampers on these are not tight enough to prevent air infiltration and basically just keep out birds and larger insects (in my case not even birds, because they regularly made nests in my dryer vent). when you turn a bathroom vent on, you don't have to open an air inlet damper to make up for the air going out. Why not? It just comes from infiltration.

The value in having a fresh air intake on the fireplace itself is that the cold air for the fire is brought in there instead of dragging cold air from all over your house, through your rooms and hallways towards the fire place, which is basically what happens. Improperly done a fireplace, although heating up the room in it's direct vicinity, will likely actually cool down other places in your house that are subject to the infiltration.
BrazosDog02
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AG
I'd start with properly priming the chimney followed by properly building an upside down fire. If you are having a fire with 40mph winds outside you WILL have smoke and downdrafts and probably pretty frequently. I seriously doubt there is anything wrong with the chimney itself. Even if he shortened for aesthetics, it still must meet code requirements.
Win At Life
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AG
Code requirements on fire boxes, flues and chimney heights are all about not catching something on fire. It makes no specific allowance for drafting based on wind vortices coming off a roof line. You can definitely make a chimney height per code that will cause back-draft problems on the leeward side of a house.
aftershock
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How long is the run from firebox to chimney? Long runs occasionally need a fan installed to help draft.
GBMont3
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AG
Not sure. Had it inspected and the initial conclusion was that the wrong cap was used - something too small or insufficiently ventilated for the volume our oversized fireplace needs to move. So they're going to install a new cap and if that doesn't fix it, add a fan.
ftworthag02
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AG
[url]https://love.firerock.us/blog/how-to-identify-and-fix-common-smoke-draw-issues[/url]
aTm2004
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AG
If you built the house this year, you should still be within your warranty, right? If so, contact the builder and let them handle it.
evan_aggie
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AG
GBMont3 said:

I'm wondering a bit about chimney height. Our builder shortened it vs original design for aesthetics (his idea, not ours) and perhaps that's the issue.

Issue abates when/if we open a window or the back door.

Low/smoldering fire not the issue - this occurs while we've got the gas starter rolling pretty good too.




Call me crazy, but if you open a window or door and the problem is resolved, aren't you revealing that your chimney is square area exhaust is too great?

Think of a vacuum motor. Cover the inlet and no air flows on the other side. Open the inlet (windows open and air flows fine). Now with no windows open up you still need vacuum flow...do you have an internal 10" or 8"? Could probably test this theory by rigging something...

GBMont3
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AG
That's how this is playing out. Helps that builder lives 2 doors down and wives are friends. They're all over it.
Aggie1
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AG
Top of chimney should be at least 2' taller than tip top of tallest roof structure and not closer than 10' from any other roof penetration or A/C intake (assuming you have one), fan exhaust, dormer windows etc.
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