Musty smell in fireplace

Jen74

New Member
Sep 17, 2018
4
Chicago IL
Hi everyone. I am looking to get a little information and advice on a situation we have. We bought the house were living in a couple years ago. The house is about 10 years old. It has a wood burning fireplace. We noticed that there was a smell coming from the fireplace when spring/summer hit. It is a musty like smell. We do not use the fireplace at all and have no interest in using it really( I have Loads of allergies and allergic to many things so we prefer not to burn wood). My question is, this smell usually goes away in the cold winter months which is why we probably did not smell it when we first moved in( we moved into the house at the end of October). My guess is it is some kind of mold or moisture issue?? I am horribly allergic to mold of all kinds and get Very nasty reactions so we pretty much sealed the front of the fireplace with a plastic sheet so the smell does not get through as much( all though we still can get hints of the smell at times). I thought about contacting a chimney sweep company, but the issue is, I cannot have them clean the chimney like they normally would because stuff will get into my house and like I Said, I am horribly reactive to mold and mold toxins and do not want that stuff getting into the house in the event that this is a mold issue. I guess my question is, Who would I call in order to diagnose the problem? Also, if there is mold in the chimney/fireplace up high, how do they fix this? I am guessing they would have to use a safe remediation protocol? Not sure. Has anyone else had issues with having a musty like smell coming from their fireplace??? Would this indicate a mold issue?
 

schwaggly

Member
Sep 23, 2009
181
n.shore ma
Jen, I had a similar issue with my downstairs fireplace and chimney. The issue is air temperature and barometric pressure. You should have it swept, capped and have them put a balloon to block off air. A good chimney sweep should be mindful of your sensitivities. Chimney sweeps nowadays are neat and have filtered vacuums, even though they conjure images of a sooty Dick VanDyke.
 

Jen74

New Member
Sep 17, 2018
4
Chicago IL
Jen, I had a similar issue with my downstairs fireplace and chimney. The issue is air temperature and barometric pressure. You should have it swept, capped and have them put a balloon to block off air. A good chimney sweep should be mindful of your sensitivities. Chimney sweeps nowadays are neat and have filtered vacuums, even though they conjure images of a sooty Dick VanDyke.
Thanks for the reply. When you say they should cap the fireplace, what does this mean? I know there is a cap currently on it. Do you think maybe it is defective? Did the smell you had coming from your fireplace smell like musty mold too? Also, when they sweep the chimmey, is it possible to keep the front of the fireplace completely covered so Nothing goes into the house? That makes sense about the balloon. Now to find a good reliable company who will be mindful of my sensitivities.. Thanks for the reply.
 

yooper08

Minister of Fire
Jan 4, 2016
618
South Lyon, MI
I don't know about how much, if any, mold can/will build up in a chimney, but this is a classic issue with fireplaces.

What happens in the summer is that warm, humid air can travel down the chimney and into the house. This typically happens because of negative pressure in the house and the fact that there's little temperature difference between outside and in. Along the way it picks up odors from the chimney from the combustion byproducts that have been deposited on the flue walls.

One step to take is to have it cleaned. This, however, doesn't really fix the problem. Cleaning can't fully remove the deposits nor does it address the issue of air flowing down the chimney.

The other step is that various products exist to prevent/minimize air coming down the chimney. There are chimney balloons that you install in the fireplace. These seal the fireplace near the damper to prevent air coming down (and hot air going up in winter). There's also chimney caps that seal at the top, but at a minimum I'd go with the balloon first to prevent the air exchange from home to chimney.
 

schwaggly

Member
Sep 23, 2009
181
n.shore ma
Kinda what I said but fancier. I believe due to time of year/ temps its barometric over negative but were splitting hairs. Cap off air flow at top and put balloon for sure.
You must get it cleaned. You may need to wear a mask for a day or 2 and run some fans or suffer for years to come.
Sweeps can block off front with plastic and use HD vacuums. Go to Angieslist and find the best fit for you. Be sure to communicate your needs. If they tell you they know better than "some guys on the internet" move on to the next one.
 

Jen74

New Member
Sep 17, 2018
4
Chicago IL
I don't know about how much, if any, mold can/will build up in a chimney, but this is a classic issue with fireplaces.

What happens in the summer is that warm, humid air can travel down the chimney and into the house. This typically happens because of negative pressure in the house and the fact that there's little temperature difference between outside and in. Along the way it picks up odors from the chimney from the combustion byproducts that have been deposited on the flue walls.

One step to take is to have it cleaned. This, however, doesn't really fix the problem. Cleaning can't fully remove the deposits nor does it address the issue of air flowing down the chimney.

The other step is that various products exist to prevent/minimize air coming down the chimney. There are chimney balloons that you install in the fireplace. These seal the fireplace near the damper to prevent air coming down (and hot air going up in winter). There's also chimney caps that seal at the top, but at a minimum I'd go with the balloon first to prevent the air exchange from home to chimney.

Thanks for the reply, I appreciate it. Yes, definitely going to get a balloon put in.. I am going to check for a good chimney sweeping company. Thanks again.
 

Jen74

New Member
Sep 17, 2018
4
Chicago IL
Kinda what I said but fancier. I believe due to time of year/ temps its barometric over negative but were splitting hairs. Cap off air flow at top and put balloon for sure.
You must get it cleaned. You may need to wear a mask for a day or 2 and run some fans or suffer for years to come.
Sweeps can block off front with plastic and use HD vacuums. Go to Angieslist and find the best fit for you. Be sure to communicate your needs. If they tell you they know better than "some guys on the internet" move on to the next one.

Thanks for replying back. Yes, I have no issues with them cleaning the chimney as long as the front stays covered and nothing gets into the house. I have severe reactions so hopefully I can find a place that will work with me on this. I will check out angieslist.. Thanks again.