Smoke coming in through unused basement fireplace

[alex2112]

Hello all! I own a split-level house built in 1965 with two masonry fireplaces, one in the upstairs living room and one right beneath it in the basement. They share a chimney with separate flues. Since buying the house 3 years ago, I haven't used the fireplaces at all so I don't know their history.

This year, we decided to start using the upstairs fireplace so I had a local chimney sweep come out and do an inspection. I told him that this was the first time I would be using the fireplace, and asked that he let me know what I need to do to get the fireplace in working order. He inspected the upstairs fireplace and flue, and said that I should install a new top mounted damper and that I need a cleaning. He also recommended that I seal off the flue for the downstairs fireplace, as it's unused. I had him go ahead with the work and a few days later we had our first fire in the upstairs fireplace.

While the fire was going, our basement started filling with smoke. It was definitely coming from the downstairs fireplace. It kept happening despite open windows near the upstairs fireplace. Also, our basement has a door which closes it off from upstairs. I was upset that this happened and called the sweep again. He came back out looked at the flues briefly, and basically told me that there must be something wrong with my flues where smoke is getting into the downstairs flue and being drafted into my house despite there being a seal at the top of the flue. He said my only option is to reline everything which will run $4000-$5000. He wasn't very helpful.

My question is, I've read plenty of reports of a downdraft sucking smoke from the top of the hot flue down the other unused one, but is it possible that this could still happen even with the top of the unused flue sealed? I'm not sure what he used up there to seal it off and whether it's truly airtight. I'm just trying to figure out if there could be a simpler explanation for this other than that there must be something "wrong" with my flues. He did also suggest a cheaper quick fix of just stuffing the throat of the downstairs fireplace with insulation and just sealing it up myself to prevent smoke from coming in. Is this even a viable option or is it dangerous?

Thanks, and sorry for the long post.

 

[DAKSY]

One option is to open a window in the basement, that should mitigate the negative pressure.
The smoke must be entering the downstairs flue thru cracks or voids in the tiles in both flues.
Your sweep SHOULD have run a camera down to inspect the condition of the tiles, but evidently didn't.
You may want to hire another sweep to do just that.

 

[jetsam]

Have a sweep come see if you can drop a 6" flexible liner down either or both. Line one or both, add an insert or two, and you'll be able to heat with wood instead of making the house colder with an open fireplace.

Doesn't the downstairs fireplace have a damper? You can jam something up there to block the flue, but it should have a built in damper that can do that for you. Get a flashlight in there, it probably does.

 

[alex2112]

Have a sweep come see if you can drop a 6" flexible liner down either or both. Line one or both, add an insert or two, and you'll be able to heat with wood instead of making the house colder with an open fireplace.

Doesn't the downstairs fireplace have a damper? You can jam something up there to block the flue, but it should have a built in damper that can do that for you. Get a flashlight in there, it probably does.

Yeah, I'm calling around to get another sweep to come look at it for sure. I'm just a little disappointed because I'm a complete newbie when it comes to fireplaces, and I would have thought a sweep would have known to recommend a video inspection especially for a chimney in an unknown state. This guy just came out, looked at it, installed a new damper and sealed the other flue, then said I'm good to go. I'm hoping that another sweep might give me an option like dropping a liner in. In the meantime, is it safe to close the downstairs damper and maybe add some stuff to seal it up so that I'm not getting a downdraft pulling smoke down? I'll try the open window in the basement too, but I just want to be sure that having a fire upstairs in its current state isn't a hazard with a potential flue issue like this.

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[bholler]

Yeah, I'm calling around to get another sweep to come look at it for sure. I'm just a little disappointed because I'm a complete newbie when it comes to fireplaces, and I would have thought a sweep would have known to recommend a video inspection especially for a chimney in an unknown state. This guy just came out, looked at it, installed a new damper and sealed the other flue, then said I'm good to go. I'm hoping that another sweep might give me an option like dropping a liner in. In the meantime, is it safe to close the downstairs damper and maybe add some stuff to seal it up so that I'm not getting a downdraft pulling smoke down? I'll try the open window in the basement too, but I just want to be sure that having a fire upstairs in its current state isn't a hazard with a potential flue issue like this.

Sent from my G8142 using Tapatalk

If the top of the basement flue is truly sealed then yes you have a serious problem that needs addressed before burning again.

 

[jetsam]

Yeah, I'm calling around to get another sweep to come look at it for sure. I'm just a little disappointed because I'm a complete newbie when it comes to fireplaces, and I would have thought a sweep would have known to recommend a video inspection especially for a chimney in an unknown state. This guy just came out, looked at it, installed a new damper and sealed the other flue, then said I'm good to go. I'm hoping that another sweep might give me an option like dropping a liner in. In the meantime, is it safe to close the downstairs damper and maybe add some stuff to seal it up so that I'm not getting a downdraft pulling smoke down? I'll try the open window in the basement too, but I just want to be sure that having a fire upstairs in its current state isn't a hazard with a potential flue issue like this.

Sent from my G8142 using Tapatalk

Well, you probably wouldn't drop a liner in if you plan on keeping an open fireplace, but it depends on the size of the fireplace and the size of the flue. A 6" round liner like a wood stove uses would not be enough flue for a large fireplace.

Closing the damper should seal the flue pretty well; you shouldn't need to stuff anything up there.

I don't encourage people to stuff things up there because... well, let's say you stuff a bunch of trash bags up there, then some years pass and you (or a houseguest, or the next owner...) forget about the trash bags, open the damper, and start a fire. You're going to have a house full of very unpleasant smoke because the chimney is blocked and the trash bags are on fire.

I also don't really encourage people to use open fireplaces, probably because I grew up with 'em and am still resentful that I wasted all that wood processing! If you want to heat with wood, look into getting a wood burning insert for one or both fireplaces. It's a world of difference.

In your case, I wouldn't burn either fireplace personally, because it sounds like there's already a hole between the flues, and who knows what else is going on in there.

 

[bholler]

Well, you probably wouldn't drop a liner in if you plan on keeping an open fireplace, but it depends on the size of the fireplace and the size of the flue. A 6" round liner like a wood stove uses would not be enough flue for a large fireplace.

Closing the damper should seal the flue pretty well; you shouldn't need to stuff anything up there.

I don't encourage people to stuff things up there because... well, let's say you stuff a bunch of trash bags up there, then some years pass and you (or a houseguest, or the next owner...) forget about the trash bags, open the damper, and start a fire. You're going to have a house full of very unpleasant smoke because the chimney is blocked and the trash bags are on fire.

I also don't really encourage people to use open fireplaces, probably because I grew up with 'em and am still resentful that I wasted all that wood processing! If you want to heat with wood, look into getting a wood burning insert for one or both fireplaces. It's a world of difference.

In your case, I wouldn't burn either fireplace personally, because it sounds like there's already a hole between the flues, and who knows what else is going on in there.

You absolutly can drop a liner foran open fireplace. It just needs to be sized correctly. Chances are that is what is needed here.

 

[alex2112]

Well, you probably wouldn't drop a liner in if you plan on keeping an open fireplace, but it depends on the size of the fireplace and the size of the flue. A 6" round liner like a wood stove uses would not be enough flue for a large fireplace.

Closing the damper should seal the flue pretty well; you shouldn't need to stuff anything up there.

I don't encourage people to stuff things up there because... well, let's say you stuff a bunch of trash bags up there, then some years pass and you (or a houseguest, or the next owner...) forget about the trash bags, open the damper, and start a fire. You're going to have a house full of very unpleasant smoke because the chimney is blocked and the trash bags are on fire.

I also don't really encourage people to use open fireplaces, probably because I grew up with 'em and am still resentful that I wasted all that wood processing! If you want to heat with wood, look into getting a wood burning insert for one or both fireplaces. It's a world of difference.

In your case, I wouldn't burn either fireplace personally, because it sounds like there's already a hole between the flues, and who knows what else is going on in there.

Honestly, right now I'm just at the point where I'm kind of fascinated by an open fireplace as I've never in my life had a fireplace or a stove. For the first burn I just used a Duraflame log. I might be interested in moving toward heating with wood at some point but for now just getting my fireplace able to burn even a composite log every once in a while is good enough for me.

And as far as stuffing something up the downstairs one, I would never stuff trash bags or anything like that. I was thinking something like some fiberglass insulation and then closing the old throat damper that's in there.

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[bholler]

Honestly, right now I'm just at the point where I'm kind of fascinated by an open fireplace as I've never in my life had a fireplace or a stove. For the first burn I just used a Duraflame log. I might be interested in moving toward heating with wood at some point but for now just getting my fireplace able to burn even a composite log every once in a while is good enough for me.

And as far as stuffing something up the downstairs one, I would never stuff trash bags or anything like that. I was thinking something like some fiberglass insulation and then closing the old throat damper that's in there.

Sent from my G8142 using Tapatalk

Even if you keep the smoke from coming out the fireplace downstairs that doesnt change the fact that the smoke is not being properly contained within the liner. That makes it unsafe. That is assuming the sweep did actually seal the top of the basement flue. If he didnt it could be a completly different problem that is nowhere near as serious or expensive to fix

 

[alex2112]

Even if you keep the smoke from coming out the fireplace downstairs that doesnt change the fact that the smoke is not being properly contained within the liner. That makes it unsafe. That is assuming the sweep did actually seal the top of the basement flue. If he didnt it could be a completly different problem that is nowhere near as serious or expensive to fix

In that case, I'll just wait to see what the new sweep says about it before doing anything. Unfortunately I don't know how good of a "sealing" job the first guy did. When I look up at my chimney outside I do see some kind of cover over the basement flue, but I have no idea if he truly sealed it. Of course, it's now snowing here in MA and the new sweep is booked out to after Christmas

 

[Ashful]

One option is to open a window in the basement, that should mitigate the negative pressure.
The smoke must be entering the downstairs flue thru cracks or voids in the tiles in both flues.
Your sweep SHOULD have run a camera down to inspect the condition of the tiles, but evidently didn't.
You may want to hire another sweep to do just that.

I video'd my own with a HD video camera on a pruning pole. The same could be done today with an iphone casting to your PC or smart TV. Not a replacement for an expert opinion, but it's a damn good confirmation or refutation of one.