Help! Ash-like smell for days after burning a fire

[kellysmith619]

Hello! I am hoping to get some answers to our fireplace woes. We purchased this 1993 home exactly a year ago. We have noticed that every time we burn a fire, the house smells like ash or campfire for a few days after, despite cleaning out the ash from the chimney. We have had the chimney inspected 2 times and cleaned once. The inspection comes back clear, and they say that there isn't creosote build up. Last week we had a top seal damper put on to help with the downdraft, but the problem actually seems worse since then.
Some more information:
-The chimney is along the exterior wall of a 2 story (plus attic) house, and it goes all the way to the top (no height issue).
-We live in Indiana, so the outside temperature is already cold, and it is making the chimney air cold.
-The ash smell seems to lighten during the day when the outside temp warms up, so it is definitely related to temperature.
-Since the top damper was installed, there is a cool draft that comes in.
-There is NO smell at all when the fire is lit, and we don't have trouble actually lighting it.
-The smell typically goes away after 3-4 days, though we are on day 4 with this time and it isn't showing signs of going away. This is our first fire since the top damper was installed.

Here are my questions:
-Are there any affordable solutions to this problem? We already spent a lot on the top damper, and it just made the problem worse. I would hate to keep tossing money at this to have the same result.
-Possible solutions I have come across - adding an insert with an insulated liner, just adding an insulated liner to our current fireplace, airtight doors.....any thoughts on these? I fear that we would spend $$ to add an insert and insulated liner, and would still have a downdraft issue bc we never really fixed whatever is causing it.
-Can you have downdraft issues with inserts?

Thanks so much for helping us trouble shoot this. We are pulling our hair out, and it seems that the fireplace companies we have talked to are as confused as we are.

 

[snaple4]

Ash smell would likely be from a downdraft after the fire. Couple problems I see with this: 1-It isn’t in a basement and has a tall flue so I would be hesitant of saying you have a downdraft. 2-the tall flue should have enough pull on it to be sucking air out of your house all the time. 3-If a top damper was installed correctly then you should have minimal to no outside air coming in.

Do you still have your damper at the bottom? It is possible the air is circulating inside the chimney with the top damper closed. Do you have two fireplaces by chance?

 

[kellysmith619]

Ash smell would likely be from a downdraft after the fire. Couple problems I see with this: 1-It isn’t in a basement and has a tall flue so I would be hesitant of saying you have a downdraft. 2-the tall flue should have enough pull on it to be sucking air out of your house all the time. 3-If a top damper was installed correctly then you should have minimal to no outside air coming in.

Do you still have your damper at the bottom? It is possible the air is circulating inside the chimney with the top damper closed. Do you have two fireplaces by chance?

Thank you for the reply! They removed the bottom damper when installing the top damper. We only have 1 fireplace in the house. There is definitely a draft of some sort coming in....is it possible for cold air to seep in through the bricks? The inspections have said the chimney looks great though.

 

[snaple4]

Thank you for the reply! They removed the bottom damper when installing the top damper. We only have 1 fireplace in the house. There is definitely a draft of some sort coming in....is it possible for cold air to seep in through the bricks? The inspections have said the chimney looks great though.

can you feel the cold draft from the fireplace/chimney itself or does it seem to come from holes in the brick around the fireplace?

 

[Woody Stover]

You may have "stack effect" in the house. Warm air exits the upper part of the house and draws replacement air down the chimney. I don't know about top dampers, but they may not completely seal the top of the chimney. You can lessen stack effect by reducing air escaping the top of the house. Make sure there are no open or leaking windows upstairs, seal the attic access, seal ceiling light fixtures (I'm not sure how to safely do that.)

 

[snaple4]

, seal ceiling light fixtures (I'm not sure how to safely do that.)

you can move the insulation away and then build a box around the light making sure to keep proper clearance. Then you air seal the box. Not very fun but very effective. We use HVAC duct board when we have to do it for a customer. I know some people use wood but that takes way to much time for me.

 

[kellysmith619]

Thank you for the suggestions. He did come and confirm that it is a pressure issue. When our hvac unit kicks on, it pulls air from the fireplace. I am curious why the smell disappears after 4 days though, even though the hvac unit continues to run. Also, he really offered no solutions, other than converting it to a gas fireplace insert, which comes with a hefty price tag.

 

[spudman99]

I used to have a fireplace smell before I installed my insert. Had a top spring loaded cap with a wire to pull it down to seal. There are several issues here at play that may require a coordinated effort to remove or abate the odor.

1. Even though your chimney has been cleaned, there will always be residual creosote on the flat surfaces, or stuck to the mortar that binds the liner in place. Think of dirt on your car that you removed by blowing on it. It looks clean but there will always be a light layer of dust.

2. Air moves up or down based on two factors: temperature and barometric pressure. Cold air sinks, hot air rises. You see less odor during the day as the chimney warms up and the hot air rises. Opposite in the evening as the cold air sinks in the chimney. Even if you seal the top of the chimney, air that remains inside will rise or fall and that can bring an odor into your living space. Same for pressure, when the barometer decreases somewhat suddenly, low pressure allows air to sink and thus cause the same problem even in warm weather.

3. Sealing the bottom of the chimney will stop the issue, but then the fireplace essentially is unusable. That does not seem like an option for you. One way you can help stop the odor is to leave the top sealing damper slightly open. This will allow warm house air to rise in the chimney and escape out the top, taking the odor with it. Then of course you are constantly loosing some household heat. Others have resorted to burning a candle in the fireplace to create some heat for an updraft, that is not practical for everyday use. One final suggestion that worked for me. When my traditional fireplace was not in use and was cool, I closed the fireplace doors and cover them with a fleece blanket (with our favorite college football team logo). that stopped all of the cold drafts and the smell, trade off was looking at the blanket.

 

[Woody Stover]

Maybe the furnace can be fitted with its own outside combustion air supply, so it won't pull air from inside the envelope of the house? I'm not sure, maybe someone will chime in. Also, use the forum search feature.."fireplace chimney odor," "chimney downdraft" or similar terms.

 

[kellysmith619]

I used to have a fireplace smell before I installed my insert. Had a top spring loaded cap with a wire to pull it down to seal. There are several issues here at play that may require a coordinated effort to remove or abate the odor.

1. Even though your chimney has been cleaned, there will always be residual creosote on the flat surfaces, or stuck to the mortar that binds the liner in place. Think of dirt on your car that you removed by blowing on it. It looks clean but there will always be a light layer of dust.

2. Air moves up or down based on two factors: temperature and barometric pressure. Cold air sinks, hot air rises. You see less odor during the day as the chimney warms up and the hot air rises. Opposite in the evening as the cold air sinks in the chimney. Even if you seal the top of the chimney, air that remains inside will rise or fall and that can bring an odor into your living space. Same for pressure, when the barometer decreases somewhat suddenly, low pressure allows air to sink and thus cause the same problem even in warm weather.

3. Sealing the bottom of the chimney will stop the issue, but then the fireplace essentially is unusable. That does not seem like an option for you. One way you can help stop the odor is to leave the top sealing damper slightly open. This will allow warm house air to rise in the chimney and escape out the top, taking the odor with it. Then of course you are constantly loosing some household heat. Others have resorted to burning a candle in the fireplace to create some heat for an updraft, that is not practical for everyday use. One final suggestion that worked for me. When my traditional fireplace was not in use and was cool, I closed the fireplace doors and cover them with a fleece blanket (with our favorite college football team logo). that stopped all of the cold drafts and the smell, trade off was looking at the blanket.

Thanks so much! It seems our issue is very similar to what yours was. The smell definitely comes in with a cold draft. We are considering an insert, but I am concerned we will still have the same issue with that. Do you have any drafting issues with your insert? Was it installed in the same chimney you had the smell issues with?

 

[spudman99]

Let me break this down to perhaps help you isolate your problem.

First take a blanket or fleece throw and close of the front of your fireplace (that is cold obviously). See if that stops the smell when you have a cold spell or drop in barometric pressure. I am trying to isolate the source and nature of the smell. That effort did stop my infrequent smell.

I just finished my insert install 2 weeks ago. Yes the installation eliminated all smell, and with my 30' chimney I have excellent draft, reading 0.20in on my magnehelic gauge on high. Bear in mind I broke out my clay liner which takes away almost all residual creosote, and that also opened up enough space to install the 6" insulated liner.

I now have an insert that is pumping heat into my family room, no creosote smell, and with my good draft, no back puffing. Have not smelled a single spec of smoke in the room over the past 2 weeks.