I am having an ongoing fireplace saga that I am hoping the good folks
here can help me with. We just bought a townhouse this fall, built in
1973, with a fireplace. To make a long story short, here's the
timeline of what's been going on.
Fireplace was sealed (opening covered in plastic wrap) when we bought
the house. We unsealed it. Fire burns fine, but smoke smell and
strong draft pours in when not in use.
Did some research, found out about negative pressure - the house seals
like Tupperware so this makes a lot of sense for us. We opened a
window in the basement next to the furnace. No change.
Brought in a professional to do the sweep/inspection that we should
have done in the first place. He cleans out the chimney, fixes the
damper that was apparently never closing, removes an interred squirrel
of great antiquity. He also replaces the crown and says water has
been leaking in and causing mold for a long time.
The draft problem is now completely fixed, but the strong smell still
fills the living room and creeps around the house from there - a foul,
wet, moldy-sooty smell.
So I see two angles here. One is trying to improve the condition that
is still causing the fireplace air to come in. The other is dealing
with the nasty smell in the fireplace. But this is so far out of my
realm of experience, I am not sure. I don't mind a little soot smell,
I understand that's part of owning a fireplace, but you can't stay in
that room and breathe without opening a window.
What should we do? Will a steady regiment of fires and ventilation
improve things over time? Is there something more drastic we will
need to do? Is there something that might kill the mold we suspect is
up there? We think the fireplace may have been sealed from the
inside but exposed and leaking to the outside for the 12 years the
previous owners lived here. Is there an air-tight plasic cover or
something we could fit over it when not in use?
Any help would greatly be appreciated.
I don't know anything about fireplaces. But one possible solution
comes to mind. Rent one of those propane fired contractor space
heaters. Run that for a few hours into the fireplace to dry out and
fireplace flue and hopefully kill the mold and spores. Do this only
in warm weather and with your windows open so that you won't poison
gas yourself. Also never leave the heater unattended and have fire
safety equipment at hand in case of a fire. Ask someone knowledgeable
about the heater on operating safety.
The stink is not mold. That has probably been long gone with fires. The
stink will go on about forever though, unless you stop the downdraft. Light
a candle and hold it in front of the fp opening. Chances are, there is a
slight draft coming down and bringing the odor with it. Gets worse on damp
There are chimney caps that close off at the top and are controlled by a
chain inside the fireplace. They are spring loaded and pup open when the
chain is released. That should solve most of the problem. Keeps critters
Thanks everyone for your good advice. The plot has thickened and
unfortunately I think it's for the worse. We are going to give the
fireplace a thorough draft test as suggested. We double-checked and
we don't have an ashpit. However hubby is out of town and I am swamped
so we figured to seal it back up until he comes home and we have time
to work on it together.
The fireplace was sealed with plastic wrap when we bought the house
and all was well. While the damper was stuck open and we had a
downdraft problem, we resealed it with a garbage bag and packing tape,
and all was well. This time, after the damper has been closed, we
sealed it back up the same way. The room STILL reeks.
I opened the windows and turned on the attic fan to air it out and it
became apparent that air was still being sucked through the fireplace
and into the room from somewhere. I noticed air coming out strongly
from cracks in the mortar on the base of the hearth, as well as some
air coming in where the wooden decorative fireplace molding meets the
brick fireplace. I taped up every drafty space I could find and it's
still leaking. You can tell when the furnace turns on when the
plastic bows out and you notice the smell immediately. I can only
guess that this didn't become apparent before because so much air was
coming right down the chimney from the top. I hope that this does not
mean there are cracks in the brickwork somewhere. Rebuilding the
chimney is out of the question right now.
A phone call to the chimney sweep who swore we'd never need to seal it
again is also on today's agenda.
How about the other units in the townhouse? Have you checked with them
about their use or non-use of the fireplaces?
Perhaps you are drawing the musty air from cracks in the chimney inside
the house, like from the attic or basement. You did say you got a draft
from the chimney baseboard. Perhaps you can start there. You might check
about getting the chimney relined. I saw some system where a giant
rubber tube is inserted into the chimney from the top. The tube is
inflated and concrete is poured around the tube. When the concrete is
dry, the tube is deflated and pulled out.
I'm wondering if your chimney is ceramic or a metal pipe up a wooden
supporting shaft. Mold should not survive heat in metal or ceramic
but if leakage was into wood, that could be source.
I have a fireplace in my family room that I'm going to seal off and
put in an electric insert. Even though damper works and I have sealed
with glass screens, suction from nearby furnace brings odor into
room. Does not bother me but wife is sensitive to smoke. A second
fireplace in den does not have this problem.
Put the lit candle into the base of the fireplace (with no fire going of
course!) and see which way the flame goes - towards the living area it is a
downdraft problem, straight up into the chimney it is a good draft up. For
what it's worth a chimney in the middle of a structure is more likely to
have a better draft then one on the side or end of the structure that is
exposed to air. If there was no smell after the cleaning for a few days it
is either a critter or as suggested before wet ashes in the cleanout. Open
the cleanout door and check for dead critters and/or moisture.
you said the chimney was leaking. Where was the leak? If it was leaking
through the mortar or exterior brickwork, capping it won't make any
diffrence. It is very possible that there is a leak at the roof line (where
the chimney intersect the roof), at (or near) ground level, or somewhere in
between. If that is the case, everytime it rains you'll get a new crop of
mold. You are also slowly rotting out the mortar that holds the chimney
something important to check - many houses built in the 70s have a ash trap
and cleanout at the bottom of the chimney. clean ou thte fireplace, and take
a look at the floor - is there a metal panel or something that looks like
it should come out? if there is, its probably an ash trap - just a door you
shove the ash down when you clean out the fireplace. They collect at the
bottom of the chimney, where any live cinders can safely go out, and where
it is easy to clean up. Even if you can;t find the ash trap, go into the
basement and find the bottom of the chimney (in some cases they are located
outside, so check around there too). what you are looking for is a smallish
door somewhere down around the bottom of the chimney. If you can find it,
open it up and clean out anytyhing thats in there. You'll probably find old
birds nests, random trash, probably some ash, and who know what else.....
Shovel it all out, and if you're feeling like really making sure things are
clean, shove a shop vac nozzle in there and suck whatever is left out.....
Presumably your chimney has some sort of liner in it, Even if it does, a
leak in the chimney itself could let water in between the chimney and
Opening a basement window should be more than enough to eliminate any
backdraft caused by a furnace.
Try the candle trick that folks have suggested, but add these steps:
first, make sure your furnace is off (nor running) Which way does the candle
flame go? If it is going towards the house and not towards the chimney,
you're getting a downdraft fdrom somewhere besides the furnace. Make sure
all of your fans, blowers etc are turned off and try again. If the candle is
still blowing inward, try closing the flu and chimney cap. If its stil
lblowing inwards, you have a major leak somewhere in the chimney structure
(either that or ghosts)...
OK, with the furnace off, if the candle blows towards the fireplace, you
have an updraft (this is hwat you want). Try turning the furnace on, nad see
if the candle blows in to the house instead. If it does, your furnace is
causing the downdraft. If it still blows towards the fireplace, try closing
the basement window, and with the furnace on see which way the candle
Once you know which way the air is going, you can start addressing the
problem..... I have done restoration work on homes where people burned lots
of paper, pine, and basically trash, and all the crap that condenses out on
the chimney has actually soaked all the way through and caused a smell
inside the house. I that case we had to actaully teasr out and replace the
chimney.... If yours is only 30 years old, and not used much, you shouldn't
have any problems like that.....
Yes- Proclean and Mycodyne. Proclean will clean the fireplace and seal
the mold that is there. The Mycodyne will prevent the mold from
growing back. Comes with a 25 year warranty.
Mold Shield LLC
MK - I had a problem with a zero clearance fireplace that had bad
breath like described especially when I burned hard wood that was not
quite seasoned enough (like only 1 year drying). What worked well for
me was to install a Chimney Balloon low right above the damper above
the hearth opening. I also took a wide popcorn bowl with about a half
liter of vinegar in it and set it in the livingroom during my work day
(9 hours) to neutralize the smell. The vinegar took the smell away and
the Chimney Balloon kept the smell in the Chimney. Problem was
I just thought I'd post an update and the conclusion of my fireplace
saga, in case it's of use to the next person looking for fireplace
First we called the fireplace guys back, who said the old damper maybe
wasn't working after all and also found more suicidal squirrels. They
removed them, and installed a new damper with cage.
There was no improvement with the draft, only it was more smoke and
less foul. We were considering our options and were going to call and
give the chimney guys hell.
We decided to get one of those chimney pillows as a temporary stopgap
until we could get the problem solved once and for all. In the
meantime, we noticed that bricks on both shoulders of the fireplace
were loose and there was lots of cracked mortar and moss. There was
no direct evidence that this was causing the draft - no air coming
out, the lining was intact under the bricks, that we could see at any
rate. But it was clear that this was only going to get worse if water
and plant life kept getting in and we didn't want bricks to start
falling off the chimney.
So hubby bought a chimney pillow and some sort of masonry cement caulk
and glued the loose bricks and filled in the large cracks.
Instant cure. We weren't even trying to fix the draft problem, and I
still don't know exactly where the leak was coming from, but this
fixed it. We still get some smell when the heat or certain fans are
on, but that's expected. The chimney baloon will fix probably that.
In the meantime, without the baloon, we've had the fireplace unsealed
for a month and it's been fine.
Thanks again for everyone's help.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.